There are 2777 circuit schematics available. The Last circuit was added on Tuesday, July 11, 2017.Please note some adblockers will suppress the schematics as well as the advertisement so please disable if the schematic list is empty.

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13.8V 30-40A Power Supply (PDF)26 vote up vote down
Yaesu FT-897 - PC interface (PDF)3 vote up vote down
AT89C2051 serial COMs to LED driver6 vote up vote down
RCM710 electronic scale, technical manual including schematic3 vote up vote down
RS-232 line monitor and loopback cables3 vote up vote down
Serial to parallel converter using the AT89C20510 vote up vote down
Slave flash trigger with counting logic (Silicon Chip Mazine article)-3 vote up vote down
Filters for the RadioJove Receiver-3 vote up vote down
Autopilot: Do it yourself UAV5 vote up vote down
Bridge head-4 vote up vote down
Bat detector microphone pre-amplifiers3 vote up vote down
Visor cradle serial interface2 vote up vote down
TomTom One V3 connector pinout-1 vote up vote down
Simple CW Keyer based on Atmel ATtiny 2313-1 vote up vote down
PWM motor controller-4 vote up vote down
Single and Two Cell White LED Drivers Without Inductors4 vote up vote down
Laser link communicator project from Electronics Australia magazine0 vote up vote down
12V battery level indicator for car batteries4 vote up vote down
Bicycle rear flashing LED light2 vote up vote down
Car burglar alarm circuit7 vote up vote down
Decision maker circuit diagram3 vote up vote down
Egg timer circuit diagram, PCB layout and assembly information1 vote up vote down
Electronic candle1 vote up vote down
Flashing light / emergency beacon for vehicle0 vote up vote down
3-up decision maker circuit diagram3 vote up vote down
Headlight guard4 vote up vote down
LED dice with fast roll5 vote up vote down
Interior light extender1 vote up vote down
Little bike light using LEDs1 vote up vote down
Simple metronome using LM14584 vote up vote down
LED dice using PIC16F883 vote up vote down
Simple moisture indicator-5 vote up vote down
LM380 2.5 watt audio amplifier circuit25 vote up vote down
One transistor FM transmitter / FM bugging device3 vote up vote down
Two player quiz master game0 vote up vote down
4 channel 433MHz remote control transmitter / receiver based on SM5162 and SM5172 chips6 vote up vote down
Seatbelt reminder circuit4 vote up vote down
Solar tracker1 vote up vote down
Stereo audio amplifier based on TDA2822M-10 vote up vote down
Two LED trouble light system-1 vote up vote down
Two-tone doorbell using 555 timer0 vote up vote down
Two transistor FM transmitter / FM bug3 vote up vote down
Snore alarm electronic device1 vote up vote down
Car Ignition Coil Driver from 110V AC-4 vote up vote down
Laser beam alarm system-3 vote up vote down
Amplified zener regulator-1 vote up vote down
13.5 Watt Power Amplifier using a TL081 opamp and TIP125 / TIP120 power transistors-8 vote up vote down
Momentary High Voltage Arc Circuit - can be used to Ignite a barbeque or a Gas in a Potato Gun1 vote up vote down
Simple car battery voltage monitor2 vote up vote down
Car Battery Charger, an SCR Design with a 10 Amp rating-7 vote up vote down
Car Ignition Coil Driver from 12V DC - Can be used as an electric fence1 vote up vote down
Cat or Dog Detector - can be used to control entry on a Cat or Dog Door0 vote up vote down
Battery Charger, Current and Voltage Regulated for Sealed Lead Acid batteries-4 vote up vote down
Digital Up / Down Counter with 7-segment display-1 vote up vote down
Delayed Power Circuit using an SCR3 vote up vote down
LED flasher with "Rising and Falling" Brightness4 vote up vote down
Ground Fault Indicator-1 vote up vote down
H-Bridge Circuit1 vote up vote down
12 Volt Knight Rider LED display0 vote up vote down
Digital combination lock using pair of CD4013 CMOS chips-2 vote up vote down
Low battery cut-off circuit for a car or truck1 vote up vote down
Fish caller circuit-7 vote up vote down
Parabolic microphone project circuit (can be used with shotgun directional microphone also)-5 vote up vote down
Voltage and current regulated power supply0 vote up vote down
High current PWM controller based around a 555 timer3 vote up vote down
Electronic roulette wheel circuit diagram-1 vote up vote down
SCA Adapter - listen to advertisement free background music on FM broadcast radio7 vote up vote down
Simple Sine Wave Oscillator including a PCB layout-5 vote up vote down
Solar cell battery charger circuit diagram-4 vote up vote down
Using a speaker as a microphone - impedance matching circuit-2 vote up vote down
Sound pressure level meter1 vote up vote down
Powerful stun gun / taser circuit diagram0 vote up vote down
Simple switching power supply (mains operated)0 vote up vote down
Relatively simple thermostat circuit diagram0 vote up vote down
Electric heater thermostat0 vote up vote down
TENS Circuit diagram for muscle stimulation-3 vote up vote down
12 Volt Switching Power Supply circuit diagram and PCB layout3 vote up vote down
Ultrasonic sound detector / sniffer1 vote up vote down
Simple voltage booster based on Linear Technologies LT1372, includes PCB design-1 vote up vote down
True RMS Watt Meter2 vote up vote down
Two transistor FM transmitter circuit diagram and PCB layout-4 vote up vote down
Making a bistable from a normal relay, based on coil hysteresis1 vote up vote down
Two-button control for dangerous machines-1 vote up vote down
Bicycle LED POV (persistence of vision display) LED display-1 vote up vote down
GSM-900 Mobile Jammer Book (PDF compressed with WinRAR)0 vote up vote down
Alkaline battery charger-1 vote up vote down
PIC16F628 controlled FLL (Frequency Locked Loop) VFO for HF (PDF)1 vote up vote down
Direct Digital Synthesis VFO for HF Bands - based on Analog Devices AD7009 DDS (PDF)-1 vote up vote down
Simple Frequency Reader for conversion VFOs0 vote up vote down
The u-counter, a PIC based programmable frequency meter (PDF)0 vote up vote down
Continuous Coverage V.F.O. for H.F. (PDF)0 vote up vote down
Experimental DSB/CW QRP rig for 20 and 40 meter bands (PDF)-1 vote up vote down
PIC16F84 CW decoder (PDF)1 vote up vote down
Simple 40 meters CW QRP Transceiver (PDF)0 vote up vote down
20 meters CW QRP Transceiver (PDF)-2 vote up vote down
Heathkit modulated HeNe laser power supply kit (HK-HI1)1 vote up vote down
Easy Xenon DC-DC Converter using LM3860 vote up vote down
Large collection of strobe / photoflash circuit diagrams0 vote up vote down
Slave Flash Trigger Circuit-1 vote up vote down
Car power supply unit for digital projects, small car PCs etc0 vote up vote down
Atmel AVR ATtiny45 development board3 vote up vote down
RGB pattern generator based on an Atmel ATtiny2313 running at 20MHz-3 vote up vote down
Simple RS232 Level Converter based on a MAX232 including Eagle PCB and schematic files1 vote up vote down
AVR thermometer / thermostat based on an Atmel ATtiny23130 vote up vote down
PCB exposure countdown timer based on an Atmel ATtiny23131 vote up vote down
VCR ping pong game-1 vote up vote down
Video ping pong game-1 vote up vote down
Video Clock Superimposer1 vote up vote down
Video clock superimposer using PIC16C711-2 vote up vote down
Eddie's Composting Loo fan controller-1 vote up vote down
Dual LED dice (available in kit form)-3 vote up vote down
Single LED dice kit circuit diagram0 vote up vote down
Precision Digital Altimeter0 vote up vote down
Highly accurate constant current source using LM4140, OP777 and MOSFET-1 vote up vote down
MOSFET based H-Bridge controller for DC motors3 vote up vote down
Transistor delay circuits to detect if a door is open for a long period3 vote up vote down
Interfacing a DSLR Hotshoe to an Arduino8 vote up vote down
Single supply op-amp audio amplifier-3 vote up vote down
USB 0-500MHz RF Power Meter based on a AD8307-1 vote up vote down
Serial LCD controller using a PIC16F6282 vote up vote down
Advanced LED temperature indicator3 vote up vote down
Simple AM transmitter using a BFW10 FET0 vote up vote down
Clap operated remove control for fans1 vote up vote down
Dry cell battery charger3 vote up vote down
Electronics Cricket on board2 vote up vote down
Electronics Lucky Number1 vote up vote down
Simple FM receiver based on a TEA5591 IC-5 vote up vote down
Long Time Period Automatic Timer0 vote up vote down
Microprocessor based home security system2 vote up vote down
PC-based candle ignitor (parallel port based design)0 vote up vote down
PC-Based DC Motor Speed Controller0 vote up vote down
Power Supply Resumption Alarm using 555 timer-2 vote up vote down
Presure based hit switch0 vote up vote down
Sensitive Optical Burglar Alarm-1 vote up vote down
Simple FM transmitter using a single transistor1 vote up vote down
Simple quiz display using 74 series logic chips0 vote up vote down
Single chip dice using a 4060 chip1 vote up vote down
Solid-state voltage indicator with high voltage cutout0 vote up vote down
Sound operated music bell using 555 timer-1 vote up vote down
Stabilized Power Supply With Short-Circuit Indication0 vote up vote down
Stereo audio simulator2 vote up vote down
Temperature Indicator Using AT89C521 vote up vote down
Touch operated Band switch for Radio Set0 vote up vote down
Trangular wave generator-1 vote up vote down
Capacitor voltage stepper using 555 timer0 vote up vote down
White / LF noise generator-1 vote up vote down
Wind Sound Generator0 vote up vote down
Home Built Laser Projector0 vote up vote down
Arduino Mega 2560 schematic (PDF) - Arduino R3-3 vote up vote down
DPA 220 amplifier schematic-3 vote up vote down
Low impedance microphone amplifier-2 vote up vote down
DPA 440 amplifier schematic-3 vote up vote down
Low pass filter for subwoofer1 vote up vote down
Portable Mixer with high-quality modular design (9V battery powered)0 vote up vote down
100W audio amplifier including PCB layout-19 vote up vote down
Quadraphonic Amplifier based on pair of LM1877 devices-3 vote up vote down
DPA 880 amplifier schematic-3 vote up vote down
Class-A/AB Amplifier delivering 100W into a 4 ohm load-5 vote up vote down
Audio Indicator - monitor a loudspeaker, alarm, or audio source for presence of an audio waveform0 vote up vote down
Stereo Audio Isolator0 vote up vote down
Guitar Reverb Effect Version 2-2 vote up vote down
Guitar Reverb Pedal0 vote up vote down
Voltage Controlled Panner2 vote up vote down
25 Watt MOSFET Audio Amplifier using IRF532 / IRF9532 hexfet transistors for output stage1 vote up vote down
Large capacitor charge "controllers" (Car Audio)0 vote up vote down
Easy to build DIY 50W amplifier based on ICL80634 vote up vote down
Audio VU Meter based on pair of LM324 quad opamps-3 vote up vote down
Voice-Over Circuit-1 vote up vote down
20 Watt Audio Power Amplifier using TDA2005M-2 vote up vote down
22 Watt Stereo Amplifier using TDA1554-2 vote up vote down
Two Transistors Audio Amplifier0 vote up vote down
10 Watt Audio Amplifier circuit diagram-4 vote up vote down
Underwater microphone used in a home aquarium to monitor fish sounds0 vote up vote down
DIY intervalometer for Sony NEX 5N camera0 vote up vote down
DIY DC Amp Volt Watt Meter using an Arduino and ZXCT10100 vote up vote down
DIY Infrared Thermometer using Arduino Nano and MLX906140 vote up vote down
Speed limit alert-1 vote up vote down
Motorcycle Alarm1 vote up vote down
Car Alarm and Immobilizer0 vote up vote down
Car Hijack Alarm0 vote up vote down
Motorcycle Alarm Number 20 vote up vote down
Motorcycle Alarm Number 3-1 vote up vote down
Motorcycle Alarm Number 4-2 vote up vote down
Motorcycle Alarm Number 5 & 6-1 vote up vote down
Park-Aid - Three LEDs signal bumper-barrier distance-1 vote up vote down
Headlight Flasher3 vote up vote down
Car Voltage Gauge with 7-segment readout0 vote up vote down
Car Water Temperature Gauge with 7-segment readout0 vote up vote down
Auto Burglar Alarm-1 vote up vote down
Automotive Speed Indicator-1 vote up vote down
Simple but reliable car battery tester using LM39141 vote up vote down
Automotive 12V to +-20V converter (for audio amplifier)0 vote up vote down
Electronic car ignition1 vote up vote down
Car battery charger with automatic cutoff-2 vote up vote down
Automatic Headlight Brightness Switch3 vote up vote down
Dome Lamp Dimmer0 vote up vote down
Light switch using LDR0 vote up vote down
Digital Remote Thermometer0 vote up vote down
Fridge door Alarm0 vote up vote down
Room Noise Detector0 vote up vote down
Capacitive Sensor0 vote up vote down
Ultra-simple Voltage Probe0 vote up vote down
Emergency Light & Alarm1 vote up vote down
Heating System Thermostat-1 vote up vote down
Touch switch based on CD4011 flip-flop-1 vote up vote down
Door Alarm circuit diagram1 vote up vote down
Mains Remote-Alert - Remotely operates beeper and/or a LED via mains supply line-1 vote up vote down
Low Voltage Alarm for batteries and other volatile DC power sources-1 vote up vote down
Touch activated switch using CD4011 CMOS NAND gate1 vote up vote down
Voice activated switch (VOX) circuit diagram0 vote up vote down
Everything-that-moves alarm works by inducing eddy currents in living beings1 vote up vote down
Electronic locker digital combination lock circuit diagram0 vote up vote down
Electronic Eavesdropping Devices Detector1 vote up vote down
Simple Infa-Red Remote Control0 vote up vote down
IR Remote Control Extender Circuit1 vote up vote down
Gate alarm0 vote up vote down
Circuit diagram for 5 Zone Alarm System1 vote up vote down
Miniature Loop Alarm3 vote up vote down
Modular Burglar Alarm0 vote up vote down
Water Activated Alarm1 vote up vote down
Novel buzzer using a relay and transformer-1 vote up vote down
Radio Wave Alarm0 vote up vote down
Enhanced 5 Digit Alarm Keypad-1 vote up vote down
Enhanced 4 Digit Alarm Keypad0 vote up vote down
Automatic Intruder Alarm1 vote up vote down
Single Zone CMOS Alarm-1 vote up vote down
Travel Touch Alarm2 vote up vote down
UltraSonic Radar0 vote up vote down
Cuckoo sound Generator2 vote up vote down
TRIAC Light Dimmer2 vote up vote down
LEDs or Lamps Sequencer is versatile modular design with no limits on number of lights-2 vote up vote down
Battery-powered Night Lamp1 vote up vote down
Courtesy light circuit diagram0 vote up vote down
Brightness Control for small Lamps-1 vote up vote down
12VDC Fluorescent Lamp Driver-1 vote up vote down
LED Chaser using 4011 / 4017 CMOS chips-2 vote up vote down
Adjustable Strobe Light0 vote up vote down
Fading LEDs0 vote up vote down
Dancing LEDs circuit diagram0 vote up vote down
Black Light powered by a 6 volt battery0 vote up vote down
DC Motor Control Circuit1 vote up vote down
Fan control based on a TL082 opamp and IRF510 power MOSFET0 vote up vote down
Bicycle back Safety Light0 vote up vote down
Simple LASER Transmitter/Receiver using HeNe laser tube2 vote up vote down
LASER Transmitter/Receiver using Pulse Width Modulator (PWM) for 12V / 24V applications1 vote up vote down
Nocturnal Animals Whisker1 vote up vote down
Seven Component Regulated LED Lamp2 vote up vote down
LED Mood Light-3 vote up vote down
13 Color LED Rainbow circuit diagram4 vote up vote down
Lightning Activated Camera Shutter Trigger0 vote up vote down
Electronic Canary0 vote up vote down
Metronome Circuit2 vote up vote down
Sun - Up Alarm that provides an audible alarm when the sun comes up or a dark area is illuminated0 vote up vote down
Assortment of Siren Circuits0 vote up vote down
60 LED Clock-2 vote up vote down
Bike Light Flasher0 vote up vote down
Simple 120 VAC motor speed controller based on a TRIAC-1 vote up vote down
PIC Light Chaser using PIC16C84-1 vote up vote down
Wire tracer-2 vote up vote down
Flashing neon christmas lights0 vote up vote down
Doorbell for the Deaf-1 vote up vote down
Insect Repellant-2 vote up vote down
220 Volts Flashing Lamps-4 vote up vote down
IR Audio link0 vote up vote down
Wireless IR headphone transmitter0 vote up vote down
Wireless IR headphone receiver1 vote up vote down
IR illuminator for night-vision tv cameras and scopes0 vote up vote down
Infra Red Switch that works with commonly available remote controls0 vote up vote down
Infra Red Remote Control Extender (Mark 1)0 vote up vote down
IR Remote Control Tester0 vote up vote down
IR Remote Control Extender Circuit (Mark 2)0 vote up vote down
IR Remote Control Extender Circuit (Mark 3)0 vote up vote down
IR Remote Control Extender Circuit (Mark 4)0 vote up vote down
IR Remote Control Extender Circuit (Mark 5)0 vote up vote down
Infrared Remote Control that operates on 115 volts AC0 vote up vote down
Three channel audio spectrum analyzer0 vote up vote down
Digital Voltmeter using ICL7107-1 vote up vote down
Triangle / Squarewave Generator using a 1458 dual opamp0 vote up vote down
Beeper to find short circuits0 vote up vote down
Voltage follower with 1G ohm input resistance based on LM11 opamp-3 vote up vote down
Led display digital Voltmeter using ICL71071 vote up vote down
MOSFET transistor tester-2 vote up vote down
Precision Audio Millivoltmeter1 vote up vote down
Oscilloscope testing module (huntron circuit)4 vote up vote down
Voltage Monitor using UA741 operational amplifier-2 vote up vote down
Logic probe-1 vote up vote down
Digital Radar Speedometer-2 vote up vote down
Digital Volume Control based around CD4067 CMOS chips0 vote up vote down
Electromagnetic Field Probe with Meter Output using an LF351 opamp0 vote up vote down
Three-Level Audio Power Indicator0 vote up vote down
Beat Balance Metal Detector14 vote up vote down
Coil Coupled Operation Metal Detector-3 vote up vote down
Expanded Scale Battery Volt Meter1 vote up vote down
Pulse Reading Logic Probe1 vote up vote down
Stereo Test Tone Generator-1 vote up vote down
Continuity Tester based on 4 x 2N3904 and 1 x 2N3905 transistors2 vote up vote down
Audible Logic Probe based on LM339 operational amplifier1 vote up vote down
Single chip digital voltmeter using ICL71290 vote up vote down
Latching Continuity Tester to help find intermittent faults, has quite a few innovative features2 vote up vote down
Infrared remote control tester using a SFH2030 photodiode and a CA3140 operational amplifier0 vote up vote down
Linear Resistance Meter-2 vote up vote down
XTal Tester for testing quartz crystals based on a pair of BC550C PNP transistors-1 vote up vote down
Simple RC car for beginners (Android control via Bluetooth)1 vote up vote down
Arduino RC car (Android control via Bluetooth)-1 vote up vote down
STM32 RC car (Android control via Bluetooth)2 vote up vote down
Lighting control with Android device through Bluetooth1 vote up vote down
Android controlled RC Vehicle with real-time video (Bluetooth & Wi-Fi)-2 vote up vote down
Portable GSM900 Cellular Phone Jammer1 vote up vote down
High Power 800 MHz/AMPS Cellular Phone Jammer0 vote up vote down
Cellular Phone Jammer. Ver 2 circuit diagram0 vote up vote down
Portable AMPS Cellular Phone Jammer1 vote up vote down
Portable AMPS Cellular Phone Jammer - Dual Purpose-1 vote up vote down
PCS Phone Jammer circuit diagram0 vote up vote down
Portable PCS Cellular Phone Jammer circuit schematic0 vote up vote down
PCS Cellular Phone Jammer circuit schematic0 vote up vote down
GBPPR Cellular Phone Jammer Exciter schematic diagram1 vote up vote down
Cellular Phone Jammer RF Amplifier circuit diagram0 vote up vote down
Homebrew P2JBZ-style cellular / mobile phone jammer circuit0 vote up vote down
Self-powered Fast Battery-Tester - Tests 1.5 to 15 Volt cells1 vote up vote down
Battery Low Voltage Beeper1 vote up vote down
AA Battery Solar Charger2 vote up vote down
4 Transistor Tracking Transmitter-1 vote up vote down
AM Transmitter-4 vote up vote down
FM Telephone Bug1 vote up vote down
FM Transmitter using two transistors1 vote up vote down
AM/FM Simultaneous Transmitter Using Digital IC3 vote up vote down
Medium range transmitter using pair of 2N3904 transistors2 vote up vote down
15 watt FM transmitter circuit diagram1 vote up vote down
AM Transmitter-1 vote up vote down
Single transistor FM transmitter2 vote up vote down
Small FM transmitter using SMD components-1 vote up vote down
Miniature FM Transmitter0 vote up vote down
Low Power FM Transmitter0 vote up vote down
FM Voice Transmitter0 vote up vote down
Sensitive FM Transmitter1 vote up vote down
Small FM Transmitter0 vote up vote down
TV Signal Amplifier covers frequencies from 40MHz to 900 MHz0 vote up vote down
Linear FM 50Watt with BLY90-2 vote up vote down
Motorized Video Camera Mount-1 vote up vote down
TV Transmitter - VHF band TV transmitter using negative sound modulation and PAL video modulation-1 vote up vote down
UHF Preamplifier covers 450MHz - 800MHz based on MPSH10 / BF180 / BCY900 vote up vote down
60W Linear amplifier using IRF840 power MOSFET0 vote up vote down
Video Signal Amplifier0 vote up vote down
Cellular Phone calling Detector-1 vote up vote down
Simple Phone Tap circuit diagram-2 vote up vote down
Telephone Hold Button circuit-1 vote up vote down
Telephone recorder to record phone conversations automatically0 vote up vote down
Cellular Phone calling Detector0 vote up vote down
Phone line indicator0 vote up vote down
Isolated Telephone Interface0 vote up vote down
Telephone Record Control using 2N4360, 2N2222 and 2N21020 vote up vote down
Voice Scrambler0 vote up vote down
Phone In Use Indicator circuit diagram0 vote up vote down
Phone "Hold" With Music-1 vote up vote down
Voice / Audio Record / Playback Circuit0 vote up vote down
Simple speakerphone-1 vote up vote down
High Quality Intercom using LM380 amplifier IC0 vote up vote down
Soft Musical Telephone Ringer0 vote up vote down
Telephone amplifier-3 vote up vote down
Cut Phone Line Detector0 vote up vote down
Telephone line monitor0 vote up vote down
Phone Busy Indicator0 vote up vote down
Ringing Phone Light Flasher using optocoupler and relay0 vote up vote down
ADC conversion using ADC0804LCN and 80511 vote up vote down
Build a Tape Linearizer and a Distortion Analyzer0 vote up vote down
Peak-reading meters0 vote up vote down
Microphone polarity tester circuit diagran-1 vote up vote down
Audio Spectrum Analyzer and Equalizer Designs0 vote up vote down
Build A Stereo Synthesizer1 vote up vote down
Electronic Control for DC Motors Using Discrete Bridge Circuits (PDF)0 vote up vote down
Defeating SCMS on DAY recorders using a Sony CXD2601 chip0 vote up vote down
Bell 202 and CCITT V23 Compatible FSK Modem Circuit1 vote up vote down
Strobo Disco Light Using Standard Tube Lamp (TL)3 vote up vote down
Heartbeat Sensor (Tranduscer)1 vote up vote down
Low Cost Universal Battery Charger0 vote up vote down
26V-to-5000V DC-DC Converter-1 vote up vote down
Ring-Around LED Flasher0 vote up vote down
Black Light (UV Tube Lamp) Inverter1 vote up vote down
15 Channels Cascaded MAX455 Video Mux0 vote up vote down
Digital Encoder Circuit Using Stepper Motor2 vote up vote down
30-Khz Bandwidth High Linearity Opto-Isolated Amplifier-1 vote up vote down
Three Wire RS232 To RS485 Converter0 vote up vote down
Low-Drift High-Impedance JFET DC Voltmeter-1 vote up vote down
Telephone Circuit: Music On Hold0 vote up vote down
Loud 10-W Car Alarm Siren2 vote up vote down
Missing Pulse Detector Circuit with 555 IC-1 vote up vote down
Binaural Synthesizer/Mono to Stereo Converter for Small Speaker/Phones-1 vote up vote down
Fast Charger for Better Lead-Acid Battery Life2 vote up vote down
5 A Constant Voltage-Constant Current Regulator1 vote up vote down
Voltage Controlled Variable Gain Video Amplifier-1 vote up vote down
Tremolo Effect Circuit for Electric Guitar or Other Musical Instruments0 vote up vote down
PC Audio Signal Generator Using RS232 Port0 vote up vote down
Powerline Carrier System Transmitter for Audio (Music/Speech)0 vote up vote down
Compact 3W BTL Audio Power Amplifier TDA7056-1 vote up vote down
CamTrig - A home-made light-operated camera trigger0 vote up vote down
A simple home-made light-operated camera trigger0 vote up vote down
A home-made light-operated camera trigger using the stamp microprocessor0 vote up vote down
Resistor decade box0 vote up vote down
Gameboy MIDI interface circuit schematic and notes on Linux development for Gameboy0 vote up vote down
Octave screamer-2 vote up vote down
Atari Punk Console schematics1 vote up vote down
Build A Roomba Bluetooth Adapter-1 vote up vote down
Chaos generator-1 vote up vote down
Various CNC mill circuit diagrams and other DIY CNC mill information0 vote up vote down
5W Chinese PLL FM Transmitter With LCD Printed Circuit Board (PCB)1 vote up vote down
Simple test equipment to build0 vote up vote down
A Two-Way Morse Practice Set0 vote up vote down
Send Morse on your VHF Rig-1 vote up vote down
An end-fed antenna, L-match coupler and resistive bridge for HF-2 vote up vote down
Regenerative receiver for the AM broadcast band using two transistors0 vote up vote down
Two Valve 40m CW Transmitter1 vote up vote down
Novel crystal set requires no antenna, earth1 vote up vote down
80 meter direct conversion receiver-1 vote up vote down
3 - 12 MHz Signal Generator1 vote up vote down
A compact L-match ATU for portable use0 vote up vote down
80m ceramic resonator VXO CW transmitter0 vote up vote down
RF Power Meter for the QRP measures up to 25 watts2 vote up vote down
Converter to yune six metres on your two metre receiver0 vote up vote down
80 Metre DSB Transmitter0 vote up vote down
High quality AM through your FM stereo-2 vote up vote down
Signal Frequency Beat Frequency Oscillator0 vote up vote down
Dip Oscillator for HF1 vote up vote down
Converter to Hear Amateurs on your FM Radio1 vote up vote down
RF Actuated Keying Monitor0 vote up vote down
LF to HF Converter-1 vote up vote down
CMOS IC 1 kHz Audio Oscillator1 vote up vote down
One Valve CW transmitter0 vote up vote down
1A Variable Regulated Power Supply0 vote up vote down
Super 80 ultra-simple SSB receiver for 3.5 MHz a basic superhet0 vote up vote down
Two Tone Audio Oscillator-1 vote up vote down
Wide-swing Variable Crystal Oscillator0 vote up vote down
Palm PDA based datalogger0 vote up vote down
Traffic light controller with 20-output sequencing1 vote up vote down
4 Photo-Detector circuit with delayed release and bipolar output0 vote up vote down
5 Times Around Circuit2 vote up vote down
8 Photo-Detector Circuit Board0 vote up vote down
Fast Electronic Circuit Breaker for Model Railways0 vote up vote down
Automatic - Railway Grade Crossing Circuit (2008 design)0 vote up vote down
Audible Train Approach Warning Circuit1 vote up vote down
Across The Track Infrared Detectors0 vote up vote down
Automatic Reversing Circuit for Model Trains-1 vote up vote down
Voltage Comparator Information And Circuits0 vote up vote down
Block Occupancy Detector For DCC1 vote up vote down
Rail Crossing Diamond Protection Circuit1 vote up vote down
Automatic Railway Grade Crossing Flashers0 vote up vote down
H Bridge Motor Control Circuits0 vote up vote down
Incline Railway Control Circuit-1 vote up vote down
Infrared Proximity Detector based on Vishay TSOP4830-1 vote up vote down
LM3909 replacement using discrete components-1 vote up vote down
Model Railroad Odometer Car0 vote up vote down
Visible and Infrared Light Detectors1 vote up vote down
Turnout Anti-Derail Protection Circuits0 vote up vote down
Regulated Power Supply Circuits0 vote up vote down
Single Traffic Light Driver Circuit0 vote up vote down
Basic Solid State Relays0 vote up vote down
Unipolar and bipolar stepper motor driver circuits using 74194 and ULN2803-1 vote up vote down
Various Transistor Throttles Cicuit Schematics0 vote up vote down
Three Terminal Regulator Type Throttle (LM350K)-1 vote up vote down
1200 Watt Lamp Dimmer Circuit using Q4015LT combination Diac-2 vote up vote down
LM311 Thermostat circuit diagrams0 vote up vote down
10, 8 And 6 Step LED Circuits (CD4017)1 vote up vote down
5 Second Ramp Generator for Locomotive Sound Card Demonstration0 vote up vote down
Transformer Secondary Voltage Reduction1 vote up vote down
Adding External Meters to DC Throttles1 vote up vote down
Back And Forth - Bidirectional Bipolar Stepper Motor Driver1 vote up vote down
Grade Crossing Bell Ringer (LM555)0 vote up vote down
CA4060B Timer Circuits-1 vote up vote down
Train Mounted Camera Battery Charger1 vote up vote down
Using Common Cathode Or Anode LEDs As Bipolar LEDs0 vote up vote down
Timed Uncoupling Ramp Driver (LM555)0 vote up vote down
Colour Shifting For Bi-Colour LED's-2 vote up vote down
Light Activated Detector Circuit (LM393/LM555)-1 vote up vote down
Diode Type Constant Lighting Circuits0 vote up vote down
High Side Current Monitors (LM358, Zetex - ZXCT-1009)0 vote up vote down
Current Regulators For Light Emitting Diodes0 vote up vote down
DCC To DC - Accessory Power Supplies0 vote up vote down
Grouped DCC Block Occupancy Detectors0 vote up vote down
HIGH or LOW Power Switch For Lights or Small Motors0 vote up vote down
High Impedance Voltmeter1 vote up vote down
Incandescent LED Circuit1 vote up vote down
Model Railroad - Infrared Proximity Switch1 vote up vote down
Infrared Receiver Module Schematics0 vote up vote down
Various LM555 LED Blinker Circuits1 vote up vote down
Low Battery Voltage Cutout Circuits-1 vote up vote down
Preselect Twin Coil Switch Machine Circuit0 vote up vote down
First Across The Line Race Scorer Circuits0 vote up vote down
School Bus Signals Circuit-1 vote up vote down
N.O. Magnetic Reed Switch ON /OFF Circuit (SCR equivalent)0 vote up vote down
Servo Motor Test Circuit (LM555)1 vote up vote down
Special Function Timer Circuits (LM555)2 vote up vote down
Team digital - SCR16 - Twin Coil Switch Machine Adapter0 vote up vote down
LED Out Circuit For Tortoise Switch Machines0 vote up vote down
Push Button Motor Control Circuits0 vote up vote down
Timed DC Throttle0 vote up vote down
Efficient unipolar stepper motor driver (only uses power when it makes a step)0 vote up vote down
DCC - Zero Stretching Simulator (LM555)0 vote up vote down
10 GHz CW Radar based on a X-band Gunnplexer0 vote up vote down
Self made data-logger V2.5 (second edition)0 vote up vote down
GoldPic 3 Pulse Induction Metal Detector (has electronic kit available)1 vote up vote down
Photodiode primer and interface circuit diagrams including photovoltaic and photoconductive modes0 vote up vote down
Build a PIC controlled DDS VFO, 0 to 6 MHz1 vote up vote down
MBC5/CPLD for the GameBoy0 vote up vote down
10W 2M CW transmitter circuit diagram-1 vote up vote down
50 MHz to 10 MHz receive converter1 vote up vote down
17M to 6M transveter circuit diagram0 vote up vote down
metre receiver0 vote up vote down
Passive grid (tube based) linear amplifier0 vote up vote down
T-Match ATU (antenna tuning unit)0 vote up vote down
Fourth order Butterworth BPF circuit diagram and design notes-1 vote up vote down
Frequency counter based on PIC16F628 and LCD display-2 vote up vote down
10MHz GPS disciplined frequency standard0 vote up vote down
Iambic keyer based on a PIC16F84 or PIC16C841 vote up vote down
Chebyshev low pass filter, rolls of at 30MHz0 vote up vote down
PIC18F4550 Development Board including PCB layout suitable for home etching-1 vote up vote down
Single transistor receiver for SSB, CW, AM using a VHF dual gate MOSFET0 vote up vote down
Multi band SSB transceiver construction project1 vote up vote down
Receiver building blocks0 vote up vote down
Digital display and VFO stabiliser using a PIC microcontroller and LCD0 vote up vote down
SSB transceiver for 80M-1 vote up vote down
Simple CW transmitter for 80M-1 vote up vote down
VHF receiver converterer0 vote up vote down
A Receive Signal Decoder1 vote up vote down
Motor speed controllers1 vote up vote down
How to install LED lights to Mini-Z model car (based on PIC12C509)-1 vote up vote down
Alternative power source for Magellan GPS receivers0 vote up vote down
PIC16F84 line following robot0 vote up vote down
8 x 8 Audio-video switch1 vote up vote down
Commodore 64 24-bit parallel port interface with 82551 vote up vote down
PIC16C505 IR / wireless remote control-1 vote up vote down
DIY 2^16 encoder based on PIC-1 vote up vote down
Electronic door codelock (PIC16F84)0 vote up vote down
Automatic door opener with PIC12C508-1 vote up vote down
Full-duplex doorphone with 3 wires connection0 vote up vote down
Infrared gate for door1 vote up vote down
Infrared circuits for remote control0 vote up vote down
Serial port controller infrared transmitter (PIC16F628)0 vote up vote down
Dual light timer based on PIC - Automatically turn off the lights after 10 minutes-1 vote up vote down
3-wire serial LCD interface for the PIC0 vote up vote down
Learning IR remote control receiver using a PIC16F628-1 vote up vote down
Low impedance microphone amplifier-3 vote up vote down
RS485-like multi-drop bus with half duplex serial protocol0 vote up vote down
EPCOS Principles of SAWR-stabilized oscillators and transmitters application notes (PDF)0 vote up vote down
Circuit diagrams for 418/433 MHz short-range communication (Elektor Electronics article)3 vote up vote down
88 - 108MHz FM audio transmitter / bug circuit diagram0 vote up vote down
Circuit diagram for superregenerative receiver built by GE labs-2 vote up vote down
X10 RF daughter board - receiver circuit diagram0 vote up vote down
RX3302 433MHz superregenerative receiver module circuit diagram-1 vote up vote down
Automicro RX3304 receiver module schematic-1 vote up vote down
Automicro TM02 high power data transmitter module circuit diagram1 vote up vote down
27MHz toy car receiver L4=9 turns, .15mm wire on 4.5mm diameter tunable ferrite coil former0 vote up vote down
SAW-based 434MHz transmitter schematic with RO2101 1-port SAW resonator-2 vote up vote down
Simple VHF video transmitter / video modulator circuit diagram (not FCC approved)0 vote up vote down
500MHz video signal transmitter0 vote up vote down
RF Audio transmitter circuit diagram that operates in the AM broadcast band0 vote up vote down
49MHz walkie-talkie circuit diagram that uses only three transistors2 vote up vote down
Superregenerative 27MHz receiver-1 vote up vote down
LCD thermometer using PIC16F8710 vote up vote down
Electronic irrigation controller based on PIC0 vote up vote down
USB digital I/O extender using a PIC18F14K50-1 vote up vote down
220V live wire-in-wall scanner0 vote up vote down
Opendiag OBD-II Schematics & PCB Layout Opendiag OBD-II Schematics & PCB Layout0 vote up vote down
G Strain energy absorber1 vote up vote down
'Almost No Parts' 7-segments 12/24 Hours LED clock with PIC 16F84A or 16F628A-2 vote up vote down
FM Microphone micro-transmitter that is small and sensitive0 vote up vote down
Montreal Doppler 3 DF (direction finder) unit1 vote up vote down
A PIC-based "TDOA" RDF (radio direction finder) antenna unit2 vote up vote down
Construction details for 30 meter rig with superhet receiver and crystal controlled transmitter0 vote up vote down
All Discrete Components 40 M transceiver with super-het receiver using no IC's0 vote up vote down
Versatile L tuner for end feed wire antennas that fits in an Altoids tin.1 vote up vote down
MMR-40 40 meter rig with SSB (voice) and CW (Morse code) operating modes.1 vote up vote down
Battery voltage monitor using an LM358 op-amp1 vote up vote down
KD1JV Digital SWR / Power Meter1 vote up vote down
An 80 meter rig for the MAS contest by KD1JV1 vote up vote down
A unique PSK transceiver, Version 2 By Steven Weber, KD1JV-3 vote up vote down
(Fairly) Simple 75M SSB rig with PTT1 vote up vote down
AM Short Wave Broadcast Receiver circuit diagram-1 vote up vote down
Low Power Antenna Analyzer and ATU Tuning Aid0 vote up vote down
Voltage boost and buck circuits using Atmel AVR Tiny13V for driving a white LED-2 vote up vote down
Fixed Frequency "Tuner Dipper"0 vote up vote down
0-14 volt, 0-2 amp current limited variable power supply regulator1 vote up vote down
A Variable power supply with adjustable current limiting. 0-14V output up to 5A current.2 vote up vote down
Simple WWV receiver for 10 MHz calibration signal0 vote up vote down
Microcontroller (AT89C2051) based tachometer (PDF)0 vote up vote down
GSM SMS javljalnik ALSMS-01 (page in slovenian )SMS remote control project0 vote up vote down
Singing Christmas tree based on Microchip PIC16F840 vote up vote down
DDS/PLL based VFO synthesizer0 vote up vote down
Universal USB digimode interface supports CAT (Yaesu), CI/V (Icom) and RS-232 (Kenwood) units (PDF)0 vote up vote down
50 MHz frequency counter, voltage meter & SWR/PWR indicator1 vote up vote down
Universal frequency counter & voltage meter1 vote up vote down
Convert 2m VHF FM PMR transceiver Motorola Radius M110 into an amateur radio-1 vote up vote down
Simple CW identifier for a FM repeater (PDF)-1 vote up vote down
Transceiver to PC soundblaster interface for digital operating modes (PSK-31, RTTY, SSTV etc)0 vote up vote down
6m SSB & CW QRP transceiver-1 vote up vote down
80m SSB & CW QRP superhet transceiver0 vote up vote down
Transceiver to PC interface with a hardware DTMF detector and galvanic isolation (PDF)2 vote up vote down
Pocket sized 20m (30m) CW QRP transceiver0 vote up vote down
USB / CAT (CI-V) adapter tested with FT-8900, FTB-9800, VX-7R, VX-7, FT-817 and IC-706MkIIG0 vote up vote down
Amateur weather station to APRS interface ALWXI-01-1 vote up vote down
Collection of quartz crystal ladder filter circuit diagrams0 vote up vote down
Building a Digital Intervalometer - includes circuit diagram and suggested layout0 vote up vote down
Serial LCD Controller using Microchip PIC16F6280 vote up vote down
Arduino based motion triggered camera using a PIR sensor1 vote up vote down
Dynamo Current and Voltage Regulator-1 vote up vote down
Wideband SWR meter0 vote up vote down
Spring reverb unit0 vote up vote down
Incoming call indicator (ZIP file)0 vote up vote down
A 3m (100 MHz) small bug (ZIP file)0 vote up vote down
Digital speedometer for cars with 7-segment display of speed1 vote up vote down
PC serial port parastic mode interface for 1-wire DS18S20 and similar 1-wire temperature sensors1 vote up vote down
Homebrew Wired Remote for Canon EOS 350D Camera1 vote up vote down
Dreamcast PC serial adapter0 vote up vote down
How to use a SCART TV as a Monitor for MAME arcade game emulator1 vote up vote down
SCA Subcarrier Demodulator for FM broadcast stations1 vote up vote down
ESR Meter-4 vote up vote down
Line Output / Flyback transformer tester0 vote up vote down
LED Voltage Indicator Board-2 vote up vote down
Voice Message Recorder / Player (uses an obsolete voice recorder chip)0 vote up vote down
BC547 80M SSB QRP Transceiver0 vote up vote down
Timer circuit based on a 14536 and 4011 CMOS chips that can be calibrated using a frequency counter1 vote up vote down
Circuit diagram for basic alarm with delayed trigger0 vote up vote down
General purpose portable DC power supply using rechargeable C cells0 vote up vote down
PCB board tester and RF detector circuir diagrams0 vote up vote down
Alarm circuit to remind you to turn off your DMM (digital multimeter)-1 vote up vote down
Circuit to enable cycling a string of Christmas lights0 vote up vote down
Pseudo car alarm system-1 vote up vote down
45 to 90Hz hum filter circuit diagram0 vote up vote down
Sound alarm based on LM741 opamp and LM386 amplifier-2 vote up vote down
General purchase audio preamplifier based on pair of 2N2222 transistors-4 vote up vote down
Audible timer that can be used as a cooking timer for roasting peanuts for example0 vote up vote down
Wireless alarm FM transmitter module0 vote up vote down
Switch debouncer circuits including transistor, CMOS logic and a 555 timer based design0 vote up vote down
Percussion generator circuits0 vote up vote down
Bench power supply that allows a number of varying output voltages to be preset. Includes PCB layout0 vote up vote down
Small audio amplifier based on LM386-2 vote up vote down
Function generator based on 555 timer and three 2N2222 transistors-2 vote up vote down
Interesesting circuits using diodes ideal for education or introductory courses on electronics0 vote up vote down
Sequential flashing arrow circuit using a 4017, also includes a PCB layout1 vote up vote down
Selection of run circuits to experiment with the 4017 CMOS decade counter chip0 vote up vote down
Notes on using LEDs and various LED driver circuit diagrams1 vote up vote down
Multi-trace scope display that allows up to 4 channels to be viewed on a single oscilloscope channel-1 vote up vote down
Small circuit and PCB layout for recording to PC Sound Monitor / Pre-amp0 vote up vote down
FM Microphone transmitter / FM buf circuit diagram1 vote up vote down
Model Train Diesel & Horn Sound Module0 vote up vote down
Magentic phono cartridge phono preamp circuit diagram0 vote up vote down
Power supply metering circuits for measuring both voltage and current-1 vote up vote down
Cicuit diagram for super long range microphone for use with a shotgun microphone or parabolic dish-1 vote up vote down
Fuse or line monitor that will check the status of up to six fuses including a PCB layout0 vote up vote down
Variety of applications using a CMOS 4001 2-input NOR gate including a PCB layout0 vote up vote down
Select of interesting electronic circuits that require only a single transistor ideal for education0 vote up vote down
Small selection of useful circuits-1 vote up vote down
Variety of simple motor control circuit diagrams using SCR or TRIAC0 vote up vote down
Super mixer with microphone input / amplifier including a PCB layout1 vote up vote down
Selection of 14 oscillator circuits include sinewave, audio, logic and LED flashers0 vote up vote down
Jeopardy game circuit diagram using three CMOS logic chips1 vote up vote down
Selection of audio preamplifiers including circuits suitable for battery operation1 vote up vote down
DDS from 1-60 MHz with built-in amplifier and variable output level using Analog Devices AD98510 vote up vote down
Ericsson phone to PC serial port interface-1 vote up vote down
Network car controller provides functions for remote door locks, headlight reminder, and car finder0 vote up vote down
Emergency power system0 vote up vote down
Digital bench power supply based on a PIC16F8700 vote up vote down
Candle simulator based on a PIC12F675 microcontroller2 vote up vote down
Magnetic card reader to PC RS-232 port interface based on a PIC12F675 micro1 vote up vote down
Cat toy using a PIC12F675 and a small weighted motor to keep your cat amused0 vote up vote down
Dirt cheap video using a PIC16F819 microcontroller0 vote up vote down
Dremel drill speed controller0 vote up vote down
Talking Egyption frog box0 vote up vote down
Talking fish hack using a PIC16F819 microcontroller-1 vote up vote down
Furby Resurrection - Project that replaces the electronics in a Furby with new custom electronics-2 vote up vote down
PWM Heater fan controller based on PIC12F675-1 vote up vote down
Hexbot robot based on a PIC including source code and circuit diagram-1 vote up vote down
433MHz super remote control using a PIC12F683 to boost range0 vote up vote down
Home theater system0 vote up vote down
Beam robot / insect based on a PIC16F818 microcontroller0 vote up vote down
Infrared object detector using a PIC12F629 microcontroller-1 vote up vote down
Isolated oscilloscope probe0 vote up vote down
Telephone line simulator ideal for testing phone interface projects0 vote up vote down
Lithium Ion Battery Charger based on a PIC micro including circuit diagram and source code0 vote up vote down
Marshmallow Bazooka with a PIC12F615 based capacitor discharge ignition system0 vote up vote down
Colour Organ based on a PIC16F84 microcontroller including schematics and source code4 vote up vote down
Touch sensistive touchpad based on a PIC16F627A micro0 vote up vote down
Self-powered phone messenger based on a PIC16C819 microcontroller0 vote up vote down
Phone call interceptor to stop unsolicited phone calls0 vote up vote down
Telephone call screener with voice1 vote up vote down
Remote RF transmitter based on PIC12F675 or PIC12F629-1 vote up vote down
Remote infrared terminal for projects requiring IR communications0 vote up vote down
RS-232 to TTL level translator0 vote up vote down
DIY flying saucer / UFO using a PIC microcontroller0 vote up vote down
Solar charge controller based on a PIC microcontroller including schematic and source code0 vote up vote down
SD card interface for PIC microcontroller including schematic and source code-1 vote up vote down
Function Generator Sine / Triangle / Square / Saw / Burst Sweep Noise based on PIC16F870-1 vote up vote down
Circuit monitoring device logs for over 10 days and can log up to 32k events both digital and analog0 vote up vote down
Superprobe handheld test device based on a PIC16F8702 vote up vote down
Speech Synthesizer Development System using a PIC microcontroller0 vote up vote down
Toy car hack to turn it into a synthetic rodent0 vote up vote down
PIC micro programmer that runs under MAC, Win98, XP, Vista, DOS, Linux, etc0 vote up vote down
Video switcher to allow monitoring of multiple video cameras using a single monitor0 vote up vote down
Low cost video motion detection using a PIC16F819 and an LM339-1 vote up vote down
YoYo enhancement device using a PIC12F629 to provide LED lighting effects0 vote up vote down
Electric cockroach zapper-1 vote up vote down
Programmer PIC16F84,12C50x and EEPROM 24Cxx0 vote up vote down
Build an inexpensive Hall effect Gaussmeter0 vote up vote down
Design for a slightly more expensive Gaussmeter0 vote up vote down
Home-Built Magnetic Levitator0 vote up vote down
Project for experimenting with magnetic levitation0 vote up vote down
Adaptive Windscreen Wiper Control0 vote up vote down
Portable iPod charger0 vote up vote down
Ultrasound detector0 vote up vote down
IC tone control preamplifier using single 741 opamp-4 vote up vote down
1KHz 4th order Butterworth filter using LT1367 quad operational amplifier0 vote up vote down
1.5 volt FM transmitter circuit diagram-2 vote up vote down
10-30 watt stereo audio amplifier circuit8 vote up vote down
118MHz to 136MHz aircraft receiver circuit diagram2 vote up vote down
12V 300W 4 channel car amplifier schematic diagram3 vote up vote down
1300MHz - 1500MHz transmitter with 20 - 50mW output power0 vote up vote down
1300MHz - 1500MHz antenna with amplifier based on two MAR-8 RF amplifiers1 vote up vote down
15W mono car amplifier using TA7227P1 vote up vote down
Shortwave received circuit diagram-1 vote up vote down
Two transistor audio preamplifier with volume control2 vote up vote down
20KHz Butterworth active filter using Linear Technology LT1124, LT1355 or LT11690 vote up vote down
2W / 4W audio amplifier using pair of LA4100, LA4101 or LA4102 modules-2 vote up vote down
455KHz oscillator using FET and 455KHz IF transformer1 vote up vote down
6W mono car amplifier using BA521 or BA532 amplifier module0 vote up vote down
Basic logarithmic amplifier using op-amp and NPN transistor-4 vote up vote down
Beat frequency oscillator for AM/SW radio receivers0 vote up vote down
Direct conversion 7MHz receiver using NE6020 vote up vote down
Low voltage microphone preamplifier using LM100 vote up vote down
Micro TV transmistter0 vote up vote down
Mono audio preamplifier using single 2SC732 transistor0 vote up vote down
Relay interface to R/C receivers-1 vote up vote down
Small TV transmitter for CCTV observation0 vote up vote down
VCR head amplifier tester0 vote up vote down
Video line receiver using AD8180 vote up vote down
Wireless guitar transmitter-3 vote up vote down
Wireless microphone using 741 opamp and 2N39040 vote up vote down
WWV receiver-1 vote up vote down
Casio calculator interface schematic0 vote up vote down
Conrad Electronics MM3610D multimeter cable pinout-1 vote up vote down
1.5 GHz PLL Frequency Synthesizer1 vote up vote down
Tiny EEG interface schematic-1 vote up vote down
OpenEEG open hardware EEG project-1 vote up vote down
Fitting a JTAG interface to an iPAQ 36000 vote up vote down
Diode laser electronic circuits for atom optics0 vote up vote down
Build Your Own Video-Rate 2-photon Microscope0 vote up vote down
LED driving and controlling methods including constant current drivers and PWM brightness control-1 vote up vote down
Touch senstor based on Atmel AT90S23130 vote up vote down
VHF/UHF TV modulator0 vote up vote down
Programming hardware and softrware for 14-bit FLASH PIC microcontrollers0 vote up vote down
Single cell LED flasher with two-year battery life (LM3909 replacement)-1 vote up vote down
Volvo 164 electric fan thermostat0 vote up vote down
RS232 to RS485 converter schematic to connect PC to RS485 network0 vote up vote down
RS232 serial to USB converter cable circuit schematic0 vote up vote down
Sony RS-422 ADAT sync cable pinout0 vote up vote down
Mac to HP48 cable pinout0 vote up vote down
Digital cameras (AGFA, Olympus) to PC (COM) cable pinout0 vote up vote down
Garmin Foretrex 101,201, Forerunner 101,201 to Serial DB9 cable schematic pinout0 vote up vote down
Apple iPod and iPhone dock pinout0 vote up vote down
Palm Pilot, Palm III, V, VII, VIIx, Handera interface port pinout0 vote up vote down
Car OBDII diagnostic interface cable schematic pinout0 vote up vote down
Car OBD II J1850 PWM, J1850 VPW, ISO-9141 cables schematic pinout0 vote up vote down
Simple DTMF Repeater Controller using PIC16F840 vote up vote down
LCD clock based on AVR Attiny2313-1 vote up vote down
Music player built on microcontroller AT91SAM7S256 with ARM core0 vote up vote down
Build a Simple Bat Detector0 vote up vote down
Various radio control schematics-1 vote up vote down
Linear constant current source dimmer for a white 24-LED array1 vote up vote down
Simple current limiting for LED flashlights0 vote up vote down
Single-Wire-Telephones for caves and mines0 vote up vote down
Transverter for Converting SSB CB to LF for Thru-the-Earth Voice Communications1 vote up vote down
A simple and inexpensive laser power meter (PDF)-1 vote up vote down
101 AT Keyboard to ASCII Decoder using 68HC705J1A MCU0 vote up vote down
Traffic light controller using an Arduino microcontroller0 vote up vote down
Simple ADS-B aircraft transponder decoder based on a PIC18F2550 microcontroller1 vote up vote down
PIXpand - TI calculator to Playstation memory card interface1 vote up vote down
Constant current LED driver schematic using a pair of BC547 transistors-1 vote up vote down
Simple laser communicator0 vote up vote down
Arduino UNO based CW decoder0 vote up vote down
PIC 18 programmer (PIC18F458, PIC18F452, PIC18C252, PIC16C745, PIC18F6620, PIC18F6720)0 vote up vote down
Game boy camera PC serial interface0 vote up vote down
Build a synchronous clock locked to the mains frequency0 vote up vote down
Simple Class A Amplifier - 10W audio output0 vote up vote down
Better Volume (and Balance) control circuit diagrams0 vote up vote down
Low Noise Microphone Preamplifier-2 vote up vote down
Bridging Adapter For Audio Power Amplifiers-4 vote up vote down
Audio Millivoltmeter0 vote up vote down
'A' Weighting Filter For Audio Measurements0 vote up vote down
Simple surround sound decoder circuit schematic1 vote up vote down
Stereo Width Controllers0 vote up vote down
Power Amplifier Clipping Indicator Circuit Diagram-4 vote up vote down
Collection of phono preamplifier circuits3 vote up vote down
Digital Delay Unit For Surround Sound-1 vote up vote down
100W Guitar Amplifier Mk II circuit diagram-2 vote up vote down
Parametric And Sub-Woofer Equaliser0 vote up vote down
High Quality Audio Mixer0 vote up vote down
Simple Car Preamplifier and Artificial Earth-1 vote up vote down
Loudspeaker Protection and Muting-1 vote up vote down
Spring Reverb Unit For Guitar or Keyboards0 vote up vote down
Audio Signal Detecting Auto Power-On Unit2 vote up vote down
Soft-Start Circuit For Power Amps0 vote up vote down
Mains Power Load Sensing Automatic Switch1 vote up vote down
Thermo-Fan to keep your amplifier or other equipment cool0 vote up vote down
Guitar Vibrato Unit Circuit Diagram0 vote up vote down
Microphone Circuit Test Oscillator1 vote up vote down
Distortion analyser circuit diagram0 vote up vote down
VU And PPM Audio Metering0 vote up vote down
Variable Amplifier Impedance0 vote up vote down
The ESP SIM (Sound Impairment Monitor)0 vote up vote down
Linkwitz Cosine Burst Generator1 vote up vote down
Multiple Feedback Bandpass Filter0 vote up vote down
High quality audio preamplifier (OPA2134)-4 vote up vote down
Automatic Charger for Battery Operated Hi-Fi Preamps1 vote up vote down
Capacitance to Voltage conversion0 vote up vote down
LED dice project based on 555 timer and CD4017 decade counter0 vote up vote down
CMoy pocket headphone amplifier-1 vote up vote down
Biasing Op-Amps into Class A0 vote up vote down
Laser high-voltage power supply0 vote up vote down
THE FOX - 40 milliwatt transmitter0 vote up vote down
THE FOX 750 - 750 milliwatt transmitter0 vote up vote down
Active RF antennuator1 vote up vote down
FOX BOX - Transmitter controller0 vote up vote down
Amplified field strength meter / RF sniffer-2 vote up vote down
THE FOX - 250mw transmitter with timer2 vote up vote down
Simple Time-Difference-Of-Arrival RDF0 vote up vote down
555 Time-Difference-Of-Arrival RDF-1 vote up vote down
PIC-Bot II using Microchip PIC16LF840 vote up vote down
Arduino MIDI interface (Arduino MIDI Drum Kit and Spooky Sound Trigger)0 vote up vote down
Solar robots0 vote up vote down
Bleeper box for time reference-1 vote up vote down
3 in one tester (audio, tone generator, diode/circuit tester)-1 vote up vote down
50MHz converter project based on a NE602/SA602/NE6120 vote up vote down
AF variable frequency generator using 555 IC0 vote up vote down
Regulatable audio amplifier using a 741opamp-2 vote up vote down
HF/6M Antenna Tuner Preselector and Antenna Switcher0 vote up vote down
Bass EQ pre-amp correction for high impedance ceramic crystal pickup-2 vote up vote down
300/1200 baud BAYCOM MODEM (revision and improved)0 vote up vote down
Direct Crystal radio receiver examples1 vote up vote down
Crystal switcher using diodes0 vote up vote down
MW Enhanced Crystal Receiver using 741 IC-1 vote up vote down
455 Khz MF to AF converter used for DRM reception in a Yaesu FRG-100 receiver1 vote up vote down
Emergency light flasher schematic-1 vote up vote down
Sensitive LW/MW/SW Shortwave general coverage receiver0 vote up vote down
HAMCOM (SSTV, RTTY, FAX...) modem using PC-speaker for TX0 vote up vote down
10 meter (28MHz) band RF amplifier0 vote up vote down
12 watt audio amplifier with tone using TDA10200 vote up vote down
5 watt audio amplifier using TDA1010-1 vote up vote down
Low frequency / audio frequency dB output meter-1 vote up vote down
Basic low frequency preamplifier circuits1 vote up vote down
Microphone pre-amp with high emphasis-2 vote up vote down
MW/SW Radio receiver0 vote up vote down
Bipolar transistor RF mixer-1 vote up vote down
IC oscillator 1...30MHz using 74LS04 chip2 vote up vote down
Simple AF-oscillator / signal generator using pair on 2N2222 transistors1 vote up vote down
HF/VHF mini portable antenna tuner1 vote up vote down
Microphone preamp for portable transceivers-1 vote up vote down
Wideband VHF/UHF/SHF 22dB RF preamp with MAR-6 or MAR-8 (MSA-0885)0 vote up vote down
PTT and/or soundcard interface1 vote up vote down
PTT and soundcard interface for the TM255/4550 vote up vote down
HF 10 watt amplifier for 18MHz using a 2SC1969/2SC1944 transistor-2 vote up vote down
RF Power meter / dummy load1 vote up vote down
HAMCOM (SSTV, RTTY, FAX...) modem using serial audio for TX0 vote up vote down
HAMCOM & SoundCard MODEM using serial- or soundcard audio0 vote up vote down
SWR bridge covering HF to VHF0 vote up vote down
Active bandpass filter with TDA2320A1 vote up vote down
1 Watt audio amp using a TDA70520 vote up vote down
TM-441 9600bps packet modification0 vote up vote down
1 Watt AM transmitter for the 10 meter band (28MHz)1 vote up vote down
12-meterband QRP AM oscillator transmitter using a 2N2219 transistor0 vote up vote down
500mW AM transmitter for the 20 meter band (14MHz)-1 vote up vote down
VHF 6 Meterband RF amplifier0 vote up vote down
HF/VHF portable antenna tuner-1 vote up vote down
90S2313 AVR Robot Board1 vote up vote down
A selection of robotics projects0 vote up vote down
Digital clock based on 74 series logic0 vote up vote down
LH0032 video amplifier0 vote up vote down
LM359N video amplifier-1 vote up vote down
ATmega8 based TNC with GPS and WX support-1 vote up vote down
Atmel AVR 90s2313 based POCSAG encoder (ZIP file)0 vote up vote down
Atmel 90s2313 based TNC0 vote up vote down
ATmega48 based Nixie Clock0 vote up vote down
POCSAG encoder/decoder (Zip file)-1 vote up vote down
Simple alarm with telephone dialler interface1 vote up vote down
In-circuit electrolytic capacitor checker0 vote up vote down
Logic probe with pulser-1 vote up vote down
Telephone line simulator2 vote up vote down
Making your own RS-60E3 Remote Control for Canon EOS cameras-1 vote up vote down
Home made PBX / PABX1 vote up vote down
Headphone amplifier based on 12AX7 tubes-2 vote up vote down
Two nixie display clock0 vote up vote down
Pocket Ignignokt LED display1 vote up vote down
VFD (vacuum flourescent display) clock0 vote up vote down
Single-digit Nixie clock0 vote up vote down
Oscilloscope CRT Clock0 vote up vote down
Weston Voltmeter Clock0 vote up vote down
Using a PC power supply as a benchtop power supply0 vote up vote down
Digibox interface circuit diagram0 vote up vote down
Six-channel Mixer and Amplifier0 vote up vote down
Audio Signal Source0 vote up vote down
Random noise generator0 vote up vote down
Analog pulse counter0 vote up vote down
Analog opto-isolator0 vote up vote down
Voltage controlled amplifier2 vote up vote down
Current loop interface0 vote up vote down
Audio graphic equaliser-1 vote up vote down
Intercom preamp0 vote up vote down
Electric field & leakage detector0 vote up vote down
Pulse width modulators (PWM)0 vote up vote down
30W ultra-low distortion audio power amplifier-3 vote up vote down
Pulse width to voltage converter-1 vote up vote down
Ultrasonic remote control & alarm system-1 vote up vote down
Grand Cherokee Off-Highway Lights0 vote up vote down
Flashing LED circuit using 555 timer0 vote up vote down
Engine control unit schematics-1 vote up vote down
3 Channel Spectrum Analyzer0 vote up vote down
3 Watt FM Transmitter circuit diagram0 vote up vote down
6V to 12V Converter-1 vote up vote down
AC Motor Speed Controller0 vote up vote down
Aircraft Radio Communications Receiver-1 vote up vote down
Air flow detector using an incandescent lamp to detect airflow0 vote up vote down
Wire Loop Alarm using 4001UBE Quad NOR Gate0 vote up vote down
Circuit diagram for 8 watt audio amp1 vote up vote down
22 Watt Audio Amplifier using TDA1554 two channel audio amp chip5 vote up vote down
50 Watt Amplifier circuit diagram0 vote up vote down
Fantastic Atom Expander0 vote up vote down
Car Alarm Arming Horn Beep Canceller0 vote up vote down
Black Light1 vote up vote down
Portable CD Player Adapter For Car0 vote up vote down
Car Battery Charger-2 vote up vote down
Automatic 12V Lead Acid Battery Charger1 vote up vote down
LED Chaser0 vote up vote down
Simple Two Speed Contactor DC Motor Controller0 vote up vote down
Digital Keypad Combination Lock0 vote up vote down
Computer Controlled Frequency Counter/Logic Probe0 vote up vote down
Simple Colour Organ0 vote up vote down
7 Segment LED Counter1 vote up vote down
Crystal Radio1 vote up vote down
Circuits to computerize your room/house0 vote up vote down
TRIAC Light Dimmer1 vote up vote down
12VDC Fluorescent Lamp Driver1 vote up vote down
FM Transmitter with range of about 300 feet0 vote up vote down
Guitar Fuzz Effect0 vote up vote down
Automatic Headlight Brightness Switch0 vote up vote down
Solid State Tesla Coil/High Voltage Generator0 vote up vote down
Simple Parallel (Printer) Port Interface0 vote up vote down
12V to 120V Inverter circuit diagram-1 vote up vote down
Infa-Red Remote Control0 vote up vote down
IR Remote Control Jammer0 vote up vote down
LASER Power Supply3 vote up vote down
LASER Transmitter/Receiver0 vote up vote down
LED Thermometer0 vote up vote down
Simple Lie Detector0 vote up vote down
Light/Dark Detector drives a relay0 vote up vote down
Low Voltage Alarm0 vote up vote down
Video Stabilizer/MacroVision Removal-2 vote up vote down
FET Audio Mixer0 vote up vote down
Microphone Mixer0 vote up vote down
Pulse Width Modulation DC Motor Controller0 vote up vote down
8 Note Tune Player1 vote up vote down
Colour (Sound) Organ0 vote up vote down
Ringing Phone Light Flasher0 vote up vote down
Phone Busy Indicator0 vote up vote down
FM Telephone Bug0 vote up vote down
Cut Phone Line Detector0 vote up vote down
Simple Phone Tap Circuit0 vote up vote down
Telephone Hold Button0 vote up vote down
Telephone Recorder0 vote up vote down
Simple Polarity Tester0 vote up vote down
Water Detector With Sump/Bilge Pump Controller0 vote up vote down
Pine Racecar Victory Judge0 vote up vote down
Op Amp Radio-1 vote up vote down
Rain Detector0 vote up vote down
Time Delay Relay0 vote up vote down
Time Delay Relay II1 vote up vote down
Remote Telephone Bell Ringer0 vote up vote down
Simple Servo Controller using 555 Timer-1 vote up vote down
Flash Slave Trigger0 vote up vote down
Stepper Motor Controller using 4027 flip-flop and 4070 XOR gate0 vote up vote down
Mono To Stereo Synthesizer / Simulator0 vote up vote down
Electronic Stethoscope0 vote up vote down
Strobe light0 vote up vote down
Adjustable Strobe Light-1 vote up vote down
Basic Power Supply3 vote up vote down
High Current Power Supply-1 vote up vote down
Dual Polarity Power Supply0 vote up vote down
High Voltage High Current Power Supply0 vote up vote down
Transformerless Power Supply-1 vote up vote down
Fixed Voltage Power Supply-1 vote up vote down
Wireless Auto Tachometer2 vote up vote down
Tone Control using TDA1524A Tone Control IC-1 vote up vote down
Simple Transistor Organ0 vote up vote down
Touch Switch using 4011 CMOS NAND Gate IC0 vote up vote down
Video Activated Relay0 vote up vote down
Voltage Inverter using 555 Timer-1 vote up vote down
Voltage Inverter using LM380 audio amplifier IC-1 vote up vote down
Digital Volume Control using DS1669 Digital Pot IC0 vote up vote down
Sound Level Meter0 vote up vote down
89C2051 microcontroller programmer0 vote up vote down
JFET Bass Preamp0 vote up vote down
Dual power supply0 vote up vote down
Magnetic levitation device0 vote up vote down
Tesla power receiver0 vote up vote down
Class B series modulator-1 vote up vote down
The KD2BD Pacsat Modem0 vote up vote down
SHARP palm-top/hand-held to RS232 serial converter0 vote up vote down
1.9 Kilojoule Coil Gun-1 vote up vote down
20kV Digital High Voltage Meter2 vote up vote down
Build your own radio controlled switch from a cordless telephone0 vote up vote down
A spark throwing tesla coil made entirely of garbage0 vote up vote down
Measuring Acceleration Using a PIC Microcontroller (ADXL202 + PIC16F84A)0 vote up vote down
PIC serial communications tutorial, includes circuit diagram and PIC16F84 assembler code0 vote up vote down
Eight simple power supplies for your workbench (mainly vacuum tube based)0 vote up vote down
Build a Crystal Set (simple AM radio receiver)1 vote up vote down
Filter Choke Analyzer0 vote up vote down
Vacuum Tube Grid Leak Detector: Needs an Amplifier0 vote up vote down
A Load Box for testing power supplies-1 vote up vote down
Low resistance adapter for a DMM (digital multimeter)1 vote up vote down
Vacuum Tube Plate Detector: Needs an Amplifier1 vote up vote down
Precision Frequency Control for AM Radios - A Frequency Synthesized Local Oscillator0 vote up vote down
Miniature SWR / RF power meter circuit-1 vote up vote down
Home Brew Compass Sensor0 vote up vote down
Higher Order Analog Butterworth Filter Designs, includes on-line filter calculator-1 vote up vote down
SWTP PR-40 Printer Interface Schematics-1 vote up vote down
Interfacing Sony control stick to Empeg0 vote up vote down
Negative voltage generator0 vote up vote down
Basic Homebuilt Discrete DTL gate circuits (Diode Transistor Logic)0 vote up vote down
Electronic shutter release with ultrasonic remote control0 vote up vote down
Lazer Tag Equipment Modifications0 vote up vote down
A Serial Infrared Remote Controller1 vote up vote down
Driving high-power loads with a microprocessor0 vote up vote down
Control your camera (Canon DSLR) with your Palm PDA0 vote up vote down
Simple 10 bit DAC for the Arduino using TLC274 opamp0 vote up vote down
Connect a NTC with a wheatstone bridge to a normal AD-Input1 vote up vote down
IDE interface to a Microchip PIC16F877 microcontroller0 vote up vote down
Inexpensive APRS Weather Station0 vote up vote down
1381 solar engine0 vote up vote down
Collection of BEAM robot circuits-1 vote up vote down
Computerized Shutter Control of Canon DSLRs0 vote up vote down
Binary clock using LED matrix to display a binary clock with 6 digits of 4 binary bits each0 vote up vote down
Making an LM35 temperature recorder (based on PIC12F675) - logs to EEPROM0 vote up vote down
Schematics and C code for a PIC frequency counter operating up to about 50 MHz (7 segment)0 vote up vote down
Universal Serial Infrared Receiver-1 vote up vote down
Schematics and C code for a 0-5V PIC LCD volt meter1 vote up vote down
Driving led display matrix from a PIC micro-2 vote up vote down
Schematics and C code for a PIC frequency counter operating up to about 50 MHz (LCD)0 vote up vote down
PIC sonar (ultrasonic) range finding project with seven segment display using PIC micro1 vote up vote down
A Real Time Clock IC (DS1307) project using the PIC micro-1 vote up vote down
PIC Serial LCD project - An RS232 serial LCD interface using a standard HD44780 LCD0 vote up vote down
Stepper motor driver using PIC12F675 that offers serial port command interface0 vote up vote down
Stepper motor driver using PIC12F6750 vote up vote down
Making an LM35 temperature recorder (based on PIC12F675) - serial output0 vote up vote down
Infrared remote control with intervalometer function for Nikon cameras0 vote up vote down
IR Remote Control for Nikon cameras, standard version0 vote up vote down
Not So Tiny Power Meter - Measures power consumption for entire apartment Not So Tiny Power Meter0 vote up vote down
Accelerometer with microcontroller and display-1 vote up vote down
Using a 555 Timer as an A/D converter0 vote up vote down
Serial cable for Casio QV-200 digital camera0 vote up vote down
Locomotive signal braking module1 vote up vote down
H-Bridge Motor Control with Power MOSFETS0 vote up vote down
Connect a Serial LCD Display to Raspberry Pi0 vote up vote down
DSP-RDF Doppler Radio Direction Finder circuit schematic - complete kit available0 vote up vote down
White LED Drive Circuit0 vote up vote down
Solar Powered Garden Light with PCB layout0 vote up vote down
Low Power PLL FM Transmitter based on LMX1601 and Atmel ATtiny2313 or AT90S2313 microcontroller1 vote up vote down
Simplest LED Flasher Circuit using a 2N2222 transistor Simplest LED Flasher Circuit led-1 vote up vote down
White LED Stroboscope0 vote up vote down
4th Order Butterworth filter schematic and calculator0 vote up vote down
Wave Multiplier for music synthesizers1 vote up vote down
Infinite melody for music synthesizers0 vote up vote down
Nikon Coolpix 950 / 990 / 995 Flash-adapter0 vote up vote down
Digital clock that receives and displays the time from the Rugby MSF radio transmission (PIC16F877)-2 vote up vote down
Remote shutter (or 'cable release') for SLR and DSLR cameras0 vote up vote down
Transistor based single zone intruder alarm0 vote up vote down
CMOS single zone intruder alarm0 vote up vote down
Automatic Intruder Alarm - a simple single-zone burglar alarm circuit based on a 4011 quad NAND gate0 vote up vote down
Hijack alarm-1 vote up vote down
Two-component metal detector using a 40931 vote up vote down
Simple temperature regulated FAN speed controller0 vote up vote down
RS-232 to TTL Translator0 vote up vote down
Car acceleration meter-1 vote up vote down
Serial port I/O interface using AVR microcontroller1 vote up vote down
150W audio amplifier that's cheap to build using TIP142 / TIP147 Darlington power transistors-2 vote up vote down
Infrared motion detector circuit0 vote up vote down
LED based transistor tester LED based transistor tester1 vote up vote down
A Scenix (and PIC) Programmer0 vote up vote down
Induced voltage sensor delta-peak trigger for coilgun0 vote up vote down
Open loop pulse trigger module for coilgun-1 vote up vote down
Optical speed trap to measure the the velocity of the projectile0 vote up vote down
Optical trigger module for coilgun-1 vote up vote down
Power MOSFET module for coilgun0 vote up vote down
Three stage induced voltage triggered coilgun0 vote up vote down
Thyristor fired coilgun circuit diagram-1 vote up vote down
KITT (from Knight Rider) Car scanner using incandescant lamps-1 vote up vote down
Magnetic levitation project from Electronics Now, February 19960 vote up vote down
LNS Technologies Levitator Kit circuit diagram0 vote up vote down
Magnetic levitation project from Popular Electronics, May 19660 vote up vote down
Magnetic levitation project from Popular Electronics, May 19890 vote up vote down
Barry's magnetic levitation project0 vote up vote down
Barry's Coilgun Mark I circuit diagrams0 vote up vote down
Barry's Coilgun Mark II circuit diagrans0 vote up vote down
Barry's Coilgun Mark III circuit diagrans0 vote up vote down
Barry's Coilgun Mark IV circuit diagrans0 vote up vote down
Circuit diagram for Coilgun Pistol Pskov 1100-1 vote up vote down
MMC to PIC16F876 circuit diagram0 vote up vote down
Circuits for interfacing microcontrollers to a wide number of real-word interfaces0 vote up vote down
50O Load and Power Meter0 vote up vote down
Simple Audio Tone Control Circuit1 vote up vote down
TTL pulse counter/logic probe-2 vote up vote down
General purpose ISA interface card for PC0 vote up vote down
PC ISA Card Random Number Generator0 vote up vote down
Hardware Random Number Generator with an SX microcontroller0 vote up vote down
MIDI cable for Sound Blaster cards0 vote up vote down
PC ISA board containing a Z80 microprocessor (coprocessor card)0 vote up vote down
8088 maximum mode SBC0 vote up vote down
External antenna for the GPS-38, Magellan 2000, or Eagle Explorer GPS receivers0 vote up vote down
EZ80 single board computer schematic (Z80)0 vote up vote down
8051 Development System Circuit Board circuit diagram0 vote up vote down
Inexpensive infrared reflectometer0 vote up vote down
Sallen-Key Low Pass Filter Calculator (handles Butterworth filters, Bessel filters and Chebychev)0 vote up vote down
Multi-User Jeopardy Game (Fastest Finger First)1 vote up vote down
Commodore RF modulator0 vote up vote down
Shadow activated (or hand wave) motion detector0 vote up vote down
Constant current LED driver circuit using LM334 plus a transistor0 vote up vote down
Laser light output intensity meter0 vote up vote down
175KHz inductive pulse transmitter (PDF)0 vote up vote down
175KHz inductive pulse receiver (PDF)1 vote up vote down
1-line telephone status indicator powered from a 3V battery (PDF)0 vote up vote down
1uS light pulse descriminator plus F to V converter (PDF)0 vote up vote down
1.5V LED flasher B (PDF)0 vote up vote down
200-400 MHz voltage controlled oscillator (PDF)-1 vote up vote down
20MHz VCSEL 3mW laser test circuit (PDF)0 vote up vote down
20MHz laser light detector (PDF)2 vote up vote down
Broadband 2MHz optical fiber receiver (PDF)0 vote up vote down
Line in use indicator that handles two independent phone lines (PDF)0 vote up vote down
3KHz low-pass filter plus audio amp (PDF)2 vote up vote down
Low current LED flasher (PDF)0 vote up vote down
Pushbutton one-shot and latch (PDF)0 vote up vote down
Modulated light receiver circuit (PDF)0 vote up vote down
Micro-power 40KHz burst laser diode driver (PDF)0 vote up vote down
40KHz light receiver (PDF)0 vote up vote down
40KHz laser burst detector (PDF)0 vote up vote down
40KHz TV-VCR repeater (PDF)0 vote up vote down
4-line telephone status indicator that is polarity independent (PDF)0 vote up vote down
1uS light pulse receiver plus post amp (MISC)0 vote up vote down
Broadband 5MHz optical fiber receiver (PDF)0 vote up vote down
5W Fluorescent light intensity modulator (PDF)0 vote up vote down
Line powered 60Hz clock generator (PDF)0 vote up vote down
High-speed 75MHz light receiver (PDF)0 vote up vote down
Micro-power pulse generator (PDF)0 vote up vote down
1.5V LED flasher A (PDF)0 vote up vote down
Flashing LED advertising badge (PDF)0 vote up vote down
Flashing LED advertising badge (PDF)0 vote up vote down
Honey Bee counter (PDF)-1 vote up vote down
Power reminder beeper (PDF)0 vote up vote down
Very loud beeper (PDF)0 vote up vote down
Darkroom camera shutter timer0 vote up vote down
Capacitance type liquid level measurement (PDF)0 vote up vote down
Unplugged power cord alarm0 vote up vote down
Modulated laser diode tester (PDF)0 vote up vote down
Divide by 1.5 counter (PDF)1 vote up vote down
Door knob alarm (PDF)1 vote up vote down
Basement doorbell beeper (PDF)0 vote up vote down
Time to dust indicator - battery powered dust indicator (PDF)0 vote up vote down
Charge coupled bi-directional power MOSFET relay (PDF)0 vote up vote down
Finger touch activated switch (PDF)0 vote up vote down
High-output square wave generator (PDF)0 vote up vote down
1W Fluorescent lamp night light (PDF)0 vote up vote down
Water seepage alarm (PDF)0 vote up vote down
Machine vibration triggers hour meter (PDF)0 vote up vote down
LASER/LED light output intensity meter (PDF)0 vote up vote down
Solid state relay (PDF)0 vote up vote down
Digital noise generator (PDF)0 vote up vote down
D Flip-flot one-shot circuits (PDF)0 vote up vote down
Low-power optical interrupter (PDF)-1 vote up vote down
Micro-power over temperature alarm (PDF)-1 vote up vote down
Machine power loss beepter (PDF)0 vote up vote down
Simple nitrogen spark generator (PDF)0 vote up vote down
Pulsed LED test circuit (PDF)1 vote up vote down
Low battery voltage flasher (PDF)2 vote up vote down
Video signal edge enhancement0 vote up vote down
Long-period watchdog timer0 vote up vote down
Line-powered Xenon flash transmitter (PDF)0 vote up vote down
9V Xenon photoflash controller (PDF)0 vote up vote down
Series Notch Fliter Designer / Calculator (displays circuit diagram after calculation)0 vote up vote down
Cellular Phone calling Detector0 vote up vote down
7MHz QRP transmitter0 vote up vote down
Tone display system0 vote up vote down
Tube amplifier-2 vote up vote down
Analog Filters for Data Conversion (ADC filter)0 vote up vote down
Simple DIY BFO metal detector4 vote up vote down
Transducer Amplifiers0 vote up vote down
Equivalent circuit and SPICE model of 555 timer0 vote up vote down
ADC Input Driver DIFFERENTIAL to DIFFERENTIAL0 vote up vote down
ADC Input Driver DIFFERENTIAL to SINGLE-ENDED1 vote up vote down
ADC Input Driver FULLY DIFFERENTIAL AMPLIFIER0 vote up vote down
ADC Input Driver SINGLE-ENDED to DIFFERENTIAL-1 vote up vote down
ADC Input Driver SINGLE-ENDED to SINGLE-ENDED0 vote up vote down
Op-Amp Current Source with Floating Load including SPICE simulation0 vote up vote down
H-Bridge Power Amp circuit diagram and SPICE simulation files-4 vote up vote down
Op Amp Comparator with Hysteresis with SPICE simulation1 vote up vote down
Op Amp Precision Half-wave Rectifier including SPICE simulation0 vote up vote down
Op Amp based PID Controller circuit with SPICE simulation-1 vote up vote down
Op Amp Triangle-Wave Generator circuit diagram and SPICE simulation files0 vote up vote down
RC Low-Pass Filter with Op Amp Buffer (single pole filter) with SPICE simulation files0 vote up vote down
Single-Supply AC Inverting Op Amp amplifier with SPICE simulation0 vote up vote down
Sallen-Key Low-Pass Filter (Double-Pole) with SPICE simulation files0 vote up vote down
Wien Bridge Oscillator with SPICE simulation-1 vote up vote down
Basic Audio Amplifier including a SPICE model-1 vote up vote down
Thermostat node schematic0 vote up vote down
No-Hum Fan Controller0 vote up vote down
PIC Web Server Schematic0 vote up vote down
Micro based PIR to IR remote converter0 vote up vote down
DIY Microphone Cable for iPod Touch (2nd Gen)0 vote up vote down
Hacking the Hot Wheels Radar Gun - includes circuit of analog front end1 vote up vote down
Laser range finder and reflectivity meter for the MARS-96 international space project (PDF)1 vote up vote down
12 Volt DC Fluorescent Lamp Driver0 vote up vote down
Battery juicer provides a night light from almost flat batteries that would otherwise be discharded0 vote up vote down
Beam-break Detector For Camera Shutter or Flash Control0 vote up vote down
Dual Polarity Unregulated PSU For High-End Audio Amps0 vote up vote down
High Voltage Converter: 90V From 1.5V0 vote up vote down
Infra-red Light Barrier Using 5551 vote up vote down
Infra-Red Sensor/Monitor0 vote up vote down
IR On/Off Switch Using a PIC12F629 Microcontroller-1 vote up vote down
Infrared S/PDIF Receiver-1 vote up vote down
RC5 Repeater to extend distance of infrared remote controls-2 vote up vote down
Super Simple 3 Watt Audio Power Amplifier based on TDA10150 vote up vote down
Transistor Tester1 vote up vote down
VGA to BNC Adapter (Converter)0 vote up vote down
White LED Lamp-1 vote up vote down
Wire Tracer (Receiver)0 vote up vote down
Wire Tracer (Transmitter)0 vote up vote down
PIC ICD0 vote up vote down
Dreamcast interface-2 vote up vote down
Ultrasonic Range Finder & Imager1 vote up vote down
iPod / USB MP3 charger using MC34063 switchmode regulator0 vote up vote down
Elecraft XG2 receiver test oscillator (PDF)1 vote up vote down
Infrared beam barrier / proximity detector0 vote up vote down
Simple electronic buzzer0 vote up vote down
Big Ben sound effects generator-1 vote up vote down
Charge Monitor for 12V lead acid battery0 vote up vote down
Wiper Speed Control1 vote up vote down
PC based Frequency Meter0 vote up vote down
7 segment rolling display using PC0 vote up vote down
JAM(Just A Minute) Quiz Game Circuit0 vote up vote down
Running Message Display0 vote up vote down
Simple car battery charger0 vote up vote down
Clap activated remote control0 vote up vote down
Contactless Mains Voltage Indicator0 vote up vote down
Automatic Staircase Light 10 vote up vote down
Automatic Staircase Light 20 vote up vote down
Clack Clack Electronic Bell1 vote up vote down
Electronic Astrologer (decision maker)0 vote up vote down
Electronic dice0 vote up vote down
Light Operated Switch0 vote up vote down
Mini emergency light0 vote up vote down
Mini tester: Handles continuity testing, resistor testing, capacitor testing and diode testing0 vote up vote down
Musical Electronic Bell0 vote up vote down
MW Transmitter can be used as an inter-room radio telephone0 vote up vote down
NiCd Cell Charger-1 vote up vote down
Pocket Transmitter that can cover 20 to 25 meters with a telescopic antenna1 vote up vote down
Reflex Action Game1 vote up vote down
Simple Traffic Light Controller0 vote up vote down
Voice Amplifier-1 vote up vote down
Discrete LED Color Organ0 vote up vote down
Automatic Plant Irrigation System Circuit for Watering Plants without any Human Interference.-1 vote up vote down
BCD to 7 Segment LED Display Decoder Circuit1 vote up vote down
25W MOSFET audio amplifier1 vote up vote down
50W audio amplifier using ICL8063-3 vote up vote down
Digital volume control-1 vote up vote down
Electronic attenuator2 vote up vote down
Speech recorded using ISD25600 vote up vote down
Precision audio millivoltmeter-2 vote up vote down
Amplified ear for surveillance-3 vote up vote down
Flashing / pulsing third brake like for cars0 vote up vote down
Headlight flasher-2 vote up vote down
Speed alert - wireless portable unit1 vote up vote down
Parking aid senses distance to rear of vehicle0 vote up vote down
Automatic headlight brightness switch0 vote up vote down
Flashing heart-1 vote up vote down
Electronic millipede robot0 vote up vote down
Circuit diagram of 3V LED chaser using 40170 vote up vote down
6V ultra-bright LED chaser using 74HC40170 vote up vote down
Smart card programmer0 vote up vote down
Decoder for encoded transmissions in Videocrypt and D2MAC-1 vote up vote down
Circuit for gold wafer card1 vote up vote down
Jupiter card programemr0 vote up vote down
PIC16F84 based diode tester-1 vote up vote down
Nokia 3310 Lcd Thermometer using DS18B200 vote up vote down
Lost keys finder using HCF40690 vote up vote down
SmartCard PC Emulator0 vote up vote down
Economy radar detector0 vote up vote down
S-Video to RCA adapter0 vote up vote down
Digital pedometer circuit diagram-1 vote up vote down
Cellular Phone calling detector (detects RF field)0 vote up vote down
Cuckoo sound generator0 vote up vote down
RS-232 Laser Transceiver-1 vote up vote down
RS-232 laser transceiver-1 vote up vote down
Casio datalogger1 vote up vote down
Relay interface add-on board for PC0 vote up vote down
8-way relay interface board for PC parallel printer port0 vote up vote down
Stepper motor controller for PC parallel port0 vote up vote down
3-axis stepper motor controller for PC parallel port0 vote up vote down
Optically isolated stepper motor controller0 vote up vote down
PC based thermometer based on Dallas DS16210 vote up vote down
VGA to SCART adapter1 vote up vote down
Basic UPS Power Supply1 vote up vote down
Fuse monitor / alarm0 vote up vote down
4 watt FM transmitter circuit diagram0 vote up vote down
FM transmitter bug-1 vote up vote down
Television signal amplifier0 vote up vote down
Small radio transmitter0 vote up vote down
Electronic Eavesdropping Devices Detector (bug detector)-1 vote up vote down
20dB VHF Amplifier1 vote up vote down
30 watt FM linear amplifier circuit diagram0 vote up vote down
AM transmitter0 vote up vote down
2 Transistor FM Voice Transmitter0 vote up vote down
Linear FM 50 watt amplifier with BLY90-1 vote up vote down
15 watt FM transmitter circuit schematic0 vote up vote down
Video signal amplifier circuit0 vote up vote down
CB (27MHz citizens band) receiver-1 vote up vote down
Circuit for three axis robot arm based on stepper motors out of 5 1/4" drives0 vote up vote down
Lightning Detector-1 vote up vote down
Geomagnetic field detector0 vote up vote down
Frost alarm0 vote up vote down
Ultrasonic radar alarm0 vote up vote down
iRDA transceiver to extend IR port range up to 15 meters0 vote up vote down
Remote digital thermometer sends data over AC power line0 vote up vote down
Telephone music on hold interface0 vote up vote down
Soft musical telephone ringer0 vote up vote down
Telephone amplifier1 vote up vote down
Telephone line monitor0 vote up vote down
Cut telephone line detector0 vote up vote down
FM telephone line bug transmitter (88MHz to 94MHz)0 vote up vote down
Continuity tester using transistors-2 vote up vote down
Latching continuity tester using 40930 vote up vote down
IR remote control tester0 vote up vote down
Linear Resistance Meter-1 vote up vote down
Crystal tester circuit diagram0 vote up vote down
Capacitance meter2 vote up vote down
Digital voltmeter (DVM)0 vote up vote down
Transistor tester using 555 timer and 4027-1 vote up vote down
Function generator based upon 8038 waveform generator IC0 vote up vote down
Triangle / Square wave generator0 vote up vote down
Picoammeter circuit schematic with 4 ranges using CA3420-1 vote up vote down
Beeper to find short circuits (continuity tester)2 vote up vote down
Voltage follower with 1G ohm input resistance0 vote up vote down
Led display digital Voltmeter0 vote up vote down
MOSFET tester for N-type MOSFET transistors0 vote up vote down
Inductive meter adapter to measure inductance using a frequency counter1 vote up vote down
Crystal tester that covers a range of 32kHz to 24MHz-1 vote up vote down
Oscilloscope testing module (Huntron circuit) that shows Lissajous patterns0 vote up vote down
Voltage monitor with LED indicator-1 vote up vote down
Logic probe with 7-segment display based on 74LS00 and 74LS470 vote up vote down
Wireless transmitter for PIR using Holtek HT12E1 vote up vote down
OPT301 Laser receiver1 vote up vote down
Heartbeat transducer using infrared LED / detector0 vote up vote down
ECG amplifier with right leg drive-1 vote up vote down
High current regulated power supply0 vote up vote down
Low-voltage light dimmer0 vote up vote down
Active bandpass filters1 vote up vote down
Bandpass filters-1 vote up vote down
AM BCB radio receiver0 vote up vote down
Regenerative shortwave receiver0 vote up vote down
Miniature audio amplifier0 vote up vote down
Optical Heart Rate Monitor0 vote up vote down
PIC Project #1 - RS232 to I2C Interface0 vote up vote down
RF front-end for triple conversion GPS receiver (PDF)1 vote up vote down
Design and build your own iPod docking station0 vote up vote down
Various tube crossover circuits0 vote up vote down
Serial Port A/D-converter-1 vote up vote down
Audio amplifier output relay delay-2 vote up vote down
TV/Radio antenna cable galvanic isolator0 vote up vote down
Audio line isolator0 vote up vote down
Connect two CD-ROM drives to one soundcard0 vote up vote down
Centronics port D/A converters and low-pass filter0 vote up vote down
4-channel dimmer rack circuit diagram1 vote up vote down
Dynamic microphone to electret microphone input-1 vote up vote down
Fogger smoke machine controller0 vote up vote down
Headphone driving circuit for soundcards0 vote up vote down
Simple line mixer0 vote up vote down
Simple IR transmitter circuit0 vote up vote down
Simple infra-red detector1 vote up vote down
Experimental laser data link0 vote up vote down
Simple light sensor adapter for oscilloscope0 vote up vote down
Line level signal to microphone input adapter-1 vote up vote down
Simple two line output combiner0 vote up vote down
Adjustable power supply using LM317-1 vote up vote down
Get power out of PC parallel port0 vote up vote down
Simple microphone preamplifier0 vote up vote down
Electret microphone powering circuits-1 vote up vote down
Simple MIDI tester0 vote up vote down
Null Printer Adapter0 vote up vote down
PC speaker volume control circuit0 vote up vote down
Use amplifier phono input as line level input-1 vote up vote down
How to get power from PC to your circuits0 vote up vote down
Simple +5V power supply circuit1 vote up vote down
RS-232 surge protection0 vote up vote down
Simple RS-232 serial port buffer circuit-1 vote up vote down
Get power out of PC RS-232 port0 vote up vote down
Sound Blaster Microphone Preamplifier0 vote up vote down
Sega 3D glasses interface circuit diagrams0 vote up vote down
0-10V control for RC servos0 vote up vote down
Speaker signals to line level inputs0 vote up vote down
S-video to composite video adapter0 vote up vote down
TDR cable reflection tester (Time Domain Reflectometer)0 vote up vote down
Telephone privacy adapter0 vote up vote down
Telephone ringing circuits0 vote up vote down
Simple circuit to connect telephone equipment to audio mixer0 vote up vote down
VGA to RGB + composite sync -converter-1 vote up vote down
VGA to TV converter0 vote up vote down
VGA to PAL and NTSC converter0 vote up vote down
A-weighting filter from an old Ampex service manual0 vote up vote down
Convert Atari-style joystick to PC joystick port0 vote up vote down
Fake Joystick circuit0 vote up vote down
Using the joystick port as general purpose input0 vote up vote down
Connect other circuits to PC joystick port0 vote up vote down
HeNe laser power supply-1 vote up vote down
Video/Audio Wireless Transmitter0 vote up vote down
Using an ADXL330 accelerometer with an AVR microcontroller0 vote up vote down
Peggy - A Light Emitting Pegboard Display-1 vote up vote down
LPG leakage alarm using SEN-1327 gas sensor module (detects 4 other dangerous gases)-1 vote up vote down
Build your own iRDA SIR Transceiver (Dongle) using MCP21200 vote up vote down
Programmable Optical Slave Flash Trigger for Digital Cameras using PIC12F6751 vote up vote down
7MHz SSB Transceiver0 vote up vote down
Homebuilt MP3 Player0 vote up vote down
5 Zone Alarm Circuit circuit diagram0 vote up vote down
Strain gauge sensor interface0 vote up vote down
Ultrasonic Distance Measurer based on Freescale MC9RS08KA2 (PDF)0 vote up vote down
Model 2030 XRAY monitor instruction manual including schematics (PDF)2 vote up vote down
Rangefinder with Fast Multiple Range Capability0 vote up vote down
Laser diode transmitter RF section0 vote up vote down
DC Fault Protection Circuit for Audio Amplifiers-1 vote up vote down
Soft Power On Tester for Amplifiers0 vote up vote down
Zonk Machine and Treble Booster1 vote up vote down
Pulse Induction Metal Detector part 1 (PDF)1 vote up vote down
Pulse Induction Metal Detector part 2 (PDF)-1 vote up vote down
Lightning shutter trigger for a camera using an Arduino0 vote up vote down
Camera Axe open hardware and open software project for camera triggering0 vote up vote down
Direction sensing infrared motion detector using PIR (PDF)0 vote up vote down
Universal telephone hold0 vote up vote down
Video switcher - run up to four cameras into one video monitor (PDF)0 vote up vote down
Talking phone dial monitor (PDF)-1 vote up vote down
Stepper motor positioner0 vote up vote down
Infrared Motion Detector using a PIR sensor (PDF)1 vote up vote down
Pyroelectric Infrared (PIR) Sensor-1 vote up vote down
Mobile APRS / GPS tracking system0 vote up vote down
GPS receiver support kit0 vote up vote down
GPS receiver (Gamin, Eagle etc) to PC interface cables0 vote up vote down
Heart of LEDs0 vote up vote down
Christmas Star0 vote up vote down
Christmas tree-2 vote up vote down
Simple Skype VoIP analog adapter0 vote up vote down
Brain-Wave Machine1 vote up vote down
Cranial Electrotherapy Stimulation (CES) circuit diagram-1 vote up vote down
Lie detector2 vote up vote down
Simple lie detector-1 vote up vote down
Furby reverse-engineered circuit0 vote up vote down
Circuit and Arduino sketch for interfacing to a DS18B20 1-wire temperature sensor0 vote up vote down
TXTVb - 70cm ATV Test Generator (PDF)0 vote up vote down
BCD readout frequency counter0 vote up vote down
Binary clock circuit diagram0 vote up vote down
Experimental DDS frequency synthesizer uses the AD9851-1 vote up vote down
Dekatron circuit diagram - device used for dividing by 10 during the valve era0 vote up vote down
Circuit diagrams for making logic gates from discrete components0 vote up vote down
Simple intercom circuit diagram-1 vote up vote down
LCD Frequency Counter1 vote up vote down
Circuit for remote lighting controller using a 433MHz AM keyfob transmitter0 vote up vote down
LED matrix clock circuit diagram0 vote up vote down
Miniscope - simple all-valve 1-inch CRT oscilloscope1 vote up vote down
Positive Feedback Circuit for Isometric Muscle Experiments1 vote up vote down
Z80 Computer circuit diagram1 vote up vote down
Giant nixie clock circuit diagram0 vote up vote down
Panel-mounting clock circuit diagram0 vote up vote down
Basic 78xx series regulator mains power supply circuit diagram0 vote up vote down
Simple QRSS callsign keyer based on an Atmega AVR programmed in C0 vote up vote down
Panel Mounting Radio Frequency Counter0 vote up vote down
Giant T-shaped LED matrix display board for financial applications containing 275 8x8 LED modules-1 vote up vote down
Simple Frequency Counter0 vote up vote down
Sidereal clock project with circuit diagrams0 vote up vote down
Heathkit signal generator user manual and circuit diagram0 vote up vote down
Spectrum analyzer Mk 11 vote up vote down
Spectrum analyzer Mk 20 vote up vote down
TinyScope - simple all-valve 1-inch CRT oscilloscope0 vote up vote down
Asynchronous 40-bit TTL CPU0 vote up vote down
USB charger circuit diagram1 vote up vote down
Z80 controlled Viscometer project0 vote up vote down
Wind speed logger0 vote up vote down
Wind speed logger Mk20 vote up vote down
The Great Z80 Computer Project1 vote up vote down
AVR-Based Serial Port IR Receiver0 vote up vote down
Ethernet interface for Commodore 64 computer0 vote up vote down
i2c-tiny-usb, a simple i2c interface for the usb port0 vote up vote down
LCD2USB, cheap open source text LCD interface0 vote up vote down
LEDMATRIX, a 80x32 pixel DIY LED matrix display1 vote up vote down
Interfacing ADXL202 accelerometer to PalmPilot-1 vote up vote down
SPI2CF, a fast and efficient WLAN interface for the AVR0 vote up vote down
TiltStick, a motion sensing device (USB interface to accelerometer)0 vote up vote down
Minimum Theremin Kit Schematic0 vote up vote down
FM radio for a PIC (uses TDA7000 IC which is now obsolete)0 vote up vote down
Lightning detector circuit diagram0 vote up vote down
Build an iButton electronic lock based around a AT91C2051 microcontroller (includes ASM source code)0 vote up vote down
AM receiver circuit diagram0 vote up vote down
Using an Apple II+ Computer as a Flash Intervalometer (PDF)0 vote up vote down
Heathkit Groundtrack GR-1290 VLF metal detector circuit diagram and detector coil construction notes2 vote up vote down
White's Surfmaster PI (pulse induction) metal detector schematic diagram-1 vote up vote down
Ultrasonic Radar Alarm Circuit Diagram0 vote up vote down
10 tricks for interfacing to the PIC16C5080 vote up vote down
Circuit to connect a rotary encoder to a Arduino UNO0 vote up vote down
555 Based Simple Servo Controller0 vote up vote down
Fluorescent Tube "Strip light" Driver0 vote up vote down
Field Strength Meter (FSM) covers 2Mhz - 1Ghz with peak reception at 3-200Mhz0 vote up vote down
Simple Function Generator using TL084 or other opamp0 vote up vote down
H Bridge controller for DC motors0 vote up vote down
Advanced High Voltage PSU circuit0 vote up vote down
Authentic Looking Knight Rider Led Project0 vote up vote down
6 Pole ElectroMagnet Motor (aka Simple Brushless motor)0 vote up vote down
88-108Mhz FM Radio Transmitter with 3 transistor stages1 vote up vote down
Serial servo controller for interfacing hobby servos via RS232 to a PC0 vote up vote down
Solid State Tesla Coil and Wireless Power0 vote up vote down
Tesla coil construction project0 vote up vote down
12 Vdc - 120 Vac Inverter Schematic0 vote up vote down
POV Persistence Of Vision 2 x 32 LED display1 vote up vote down
Vareity of circuits for interfacing to/from TTL logic0 vote up vote down
Victoria TAFE programmer (based on AT89C2051)0 vote up vote down
JDM programmer circuit diagram0 vote up vote down
PIC micro programmer circuit diagram0 vote up vote down
Dinsmore 1490 digital compass0 vote up vote down
Geiger counter circuit diagram-1 vote up vote down
Speech recognition using HM20070 vote up vote down
PIC microcontroller servo motor interface0 vote up vote down
PIC micro multiple servo motor interface0 vote up vote down
Electric field disturbance monitor0 vote up vote down
3 KHz low pass filter plus audio amplifier circuit diagram0 vote up vote down
Micropower pulse generator (PDF)0 vote up vote down
Inexpensive seismometer project0 vote up vote down
Constant current LED driver circuit using an NPN transistor to control an N-channel MOSFET0 vote up vote down
Simple 430MHz band FM transmitter uses only 2 FETtransistors0 vote up vote down
110mW emitter follower audio power amplifier0 vote up vote down
AM transmitter using no power supply1 vote up vote down
NE555 drives a speakes: Pulse Width Modulation Amplifier-1 vote up vote down
UHF signal generator0 vote up vote down
VHF signal generator0 vote up vote down
Judge Dredd pinball locking ring modification0 vote up vote down
PIC micro frame grabber (TDA8708)0 vote up vote down
Digitally Addressable DALI Dimming Ballast (PDF)0 vote up vote down
New and Improved Sound Card Packet Interface tested with PSK31 and APRS0 vote up vote down
Home security project0 vote up vote down
PC Controlled RC car construction project0 vote up vote down
Pulse Circuits for Infrared LEDs and Visible Diode Lasers-1 vote up vote down
Pulse Circuits for Infrared LEDs and Visible Diode Lasers2 vote up vote down
LED Modulation Circuits including 5MHz and 50MHz versions0 vote up vote down
Measuring the speed of light with an infrared LED / photodiode (TDOA)0 vote up vote down
Canon DSLR cable shutter release usin 4N25 for optical isolation0 vote up vote down
Spatial Distortion Reduction Headphone Amp-1 vote up vote down
Simple GPS Stabilised 10 MHz Oscillator1 vote up vote down
Sanyo 20EZ monitor circuit diagram0 vote up vote down
Burger Time Arcade Game circuit diagram (PDF)-1 vote up vote down
Dig Dug Arcade Game (800k ZIP)0 vote up vote down
Frogger Arcade Game circuit diagram (PDF)-1 vote up vote down
Frogger Sound/ROM - FROGSND Arcade game circuit diagram (PDF)0 vote up vote down
Gyrus Arcade Game circuit diagram (PDF)0 vote up vote down
Junior Pacman Arcade Game circuit diagram (PDF)1 vote up vote down
Ladybug Arcade Game circuit diagram (PDF)1 vote up vote down
Mappy Arcade Game circuit diagram (PDF)0 vote up vote down
Moon Cresta Arcade circuit diagram (PDF)0 vote up vote down
Mr.Do Arcade Game circuit diagram (PDF)0 vote up vote down
Pengo Arcade Game circuit diagram (PDF)0 vote up vote down
PacLand Arcade Game circuit diagram (PDF)0 vote up vote down
Q*Bert Arcade Game circuit diagram (PDF)0 vote up vote down
Qix Arcade Game circuit diagram (PDF)0 vote up vote down
Scramble Arcade Game circuit diagram (PDF)-1 vote up vote down
Time Pilot'84 Arcade Game circuit diagram (PDF)0 vote up vote down
Xevious Arcade Game circuit diagram (PDF)-1 vote up vote down
Robotic microcontroller board0 vote up vote down
Single to 3-phase power conversion0 vote up vote down
Low noise PIN diode laser receiver circuit0 vote up vote down
Circuits for biasing and modulating laser diodes0 vote up vote down
inexpensive high speed microwave data link using an Alpha Gunnplexer for 10 Mbps data rate0 vote up vote down
18 dB LT1253 DDS amplifier circuit diagram1 vote up vote down
23 dB Bipolar DDS Amplifier0 vote up vote down
15M CW Transceiver design0 vote up vote down
20 Meter CW Transceiver1 vote up vote down
30 Meter, Discrete Component CW Transceiver Built Manhattan-style0 vote up vote down
K8IQY's Original 2N2/40 CW Transceiver Rig0 vote up vote down
40 to 6 Meter "No Tune" Transverter0 vote up vote down
SW30+ 30 Meter CW Transceiver0 vote up vote down
-20 dB Couplers for use with a with a spectrum analyzer or other sensitive detector0 vote up vote down
-20 dBm, 14.060 MHz Precision Signal Source0 vote up vote down
RC Audio Oscillator0 vote up vote down
Precision VXO for Crystal Characterization & Matching0 vote up vote down
Return Loss Bridge0 vote up vote down
Lossless portable digital audio player using the Microchip PIC320 vote up vote down
Water system controller (PDF)0 vote up vote down
GPS LCD Display Project0 vote up vote down
PIC16F84 LED chaser1 vote up vote down
PIC micro LED projects0 vote up vote down
PS/2 keyboard keystroke logger based on Atmel 89C20510 vote up vote down
Breadboard supply - very low dropout adjustable power supply1 vote up vote down
Bedazzler: Do-it-yourself Handheld LED-Incapacitator (non-lethal weapon)0 vote up vote down
Dimmable Li-Ion Halogen Bike Light0 vote up vote down
Solderless Breadboard Arduino Clone for Arduino prototyping0 vote up vote down
Digg Button Kit0 vote up vote down
Drawdio - A very simple musical synthesizer that uses the conductive properties of pencil graphite0 vote up vote down
Ethernet shield for Arduino (Xport)0 vote up vote down
Fuzebox - open source 8-bit game console based on Atmel ATmega644-20PU0 vote up vote down
GPS / Datalogging shield for Arduino microcontroller1 vote up vote down
Ice Tube Clock - Vacuum fluorescent display (VFD) clock0 vote up vote down
Real-world MIDI interface platform project including circuit diagram and PCB design files0 vote up vote down
Persistance of vision (POV) toy0 vote up vote down
Portable MP3 music player0 vote up vote down
Small battery-powered USB charger including circuit diagram and PCB layout1 vote up vote down
Arduino based controller interface for servo motors, stepper motors and DC motors0 vote up vote down
Arduino microcontroller prototyping system0 vote up vote down
SIM card reader circuit diagram0 vote up vote down
Persistence of Vision Display for Bikes0 vote up vote down
High power infrared remote control to turn off television sets from a distance0 vote up vote down
USBtinyISP - AVR programmer & SPI interface project0 vote up vote down
Wave Bubble self-tuning portable RF jammer0 vote up vote down
Wave Bubble - A design for a self-tuning portable RF jammer1 vote up vote down
Wave (Audio) shield for Arduino microcontroller1 vote up vote down
Bassline synthesizer/sequencer-1 vote up vote down
YBox2 - DIY networked set-top box that connects to a TV to deliver Internet content1 vote up vote down
Mini-Beacon - miniature programmable LED Flasher that is based around a PIC12F629 microcontroller0 vote up vote down
Subwoofer Filter, Gainer, Auto Power System0 vote up vote down
PC-based ISA data acquisition and control board0 vote up vote down
Circuit for driving a liquid crystal (LCD) shutter to simply pass or block light0 vote up vote down
Linux Infra-red Remote Control (LIRC)-1 vote up vote down
Simple home made ADS-B receiver that takes IF from a modified receiver1 vote up vote down
Very Simple ADSB Receiver using a TV tunder to allow reception of aircraft transponders0 vote up vote down
115200 RS232 QPSK RF modem project0 vote up vote down
Build your own MARES dive computer IRIS interface for RS2320 vote up vote down
3.3V / 5V Regulated Power Supply Circuit0 vote up vote down
Acceleration Sensing - gesture controllers for robotic musical instruments1 vote up vote down
Distance Sensing - devices for wireless distance and position determination0 vote up vote down
Doppler radar based gesture measurement system capable of delivering positional information0 vote up vote down
Infrared Body Sensing0 vote up vote down
Homebuilt RS232 LCD Interface0 vote up vote down
Lie detector0 vote up vote down
Project to capture infrared remote control signals and play them back, based on Atmel ATMEGA48 micro0 vote up vote down
MIDI Controller Footpedal0 vote up vote down
DIY Serial MIDI Interface (80C51/80C31 Version)0 vote up vote down
Homemade Serial to Nokia MBus Interface on a PCB, without using Zener diodes0 vote up vote down
Microcontroller sensor and actuator interfaces0 vote up vote down
Hi-Fi Preamp with remote-control and other advanced features-3 vote up vote down
Actvie speaker based on a dual op-amp (LM833) and TDA2030 power amp0 vote up vote down
4 channel power amplifier with bi-amping and bridging options-1 vote up vote down
Amplifier based on LM4780 including a thermal shutdown feature0 vote up vote down
Lead-Acid Battery Monitor1 vote up vote down
Complete Design for Giant 8-foot LCD Counter (Zip file)0 vote up vote down
PIC12C509 logic gate replacement for nitrogen filler (ZIP file)0 vote up vote down
PIC demo board0 vote up vote down
Disco light controller (ZIP file)0 vote up vote down
DS1821 programmable thermostat0 vote up vote down
PIC12C509 Gym Timer (ZIP file)0 vote up vote down
PIC LCD and Keypad driver-1 vote up vote down
PIC12C508 Phase Controller for 2kW heater (ZIP file)0 vote up vote down
PIC16F84 TRIAC / IGBT brightness phase controller0 vote up vote down
PIC16F84 pulse monitor with date/time output (ZIP)0 vote up vote down
Simple metal detector based on a PIC12F683 microcontroller-2 vote up vote down
Three component bat detector based on a PIC12F683 microcontroller0 vote up vote down
Mini oscilloscope based on PIC18F4620 and standard 16x2 text LCD display module1 vote up vote down
PIC based touch clock that demonstrates interfacing a PIC microcontroller to an LCD touch panel0 vote up vote down
Pico OSD, a PIC video superimposer0 vote up vote down
A PIC16F84A Alarm Clock1 vote up vote down
PIC16F877A Thermometer with MCP9700A sensor0 vote up vote down
A Voice Controlled LED Light Show using a VRStamp0 vote up vote down
PIC PAL Video Library including source code and circuit schematics0 vote up vote down
Cheap Ultrasonic Range Finder based on a PIC microcontroller0 vote up vote down
Cheap Ultrasonic Range Finder based on PIC16F877A with a 8MHz crystal0 vote up vote down
A PIC16F819 Dymoclock (also demonstrates interfacing 30 LEDs to a PIC using only six I/O pins)0 vote up vote down
MemoSound game based on a PIC16F84A-2 vote up vote down
EasyPic2 with on-board Ethernet Adapter0 vote up vote down
Automatic LED display dimmer using a LED as a light sensor-1 vote up vote down
DCF-77 PIC LED clock (DCF77 is the name of a German radio station on 77.5 KHz)0 vote up vote down
DCF77 PIC16F84A Single-Nixie clock (DCF77 is the name of a German radio station on 77.5 KHz)0 vote up vote down
Yaesu FT-736R doppler compensation0 vote up vote down
AI-1 ("All-in-one") Remote - photographic accessory that you can build0 vote up vote down
HeadBanger Headphone Amp-2 vote up vote down
Pad launch controller for model rockets0 vote up vote down
Stage center reverb unit circuit schematic0 vote up vote down
Custom USB tyre pressure monitoring system0 vote up vote down
Simple flashing light circuit0 vote up vote down
Simple flashing light circuit0 vote up vote down
A dual alternating flashing light circuit0 vote up vote down
Simple flashing light circuit0 vote up vote down
A dual tandem flashing light circuit powered by a 9 volt battery0 vote up vote down
Simulate the Gyralite (dual flashing headlights).0 vote up vote down
Moderately complex train detector using an infrared LED and an infrared detector0 vote up vote down
Simple train detector using ambient light and a photocell0 vote up vote down
Aladin interface0 vote up vote down
Homemade GPS jammer using a MC145151 frequency synthesizer-2 vote up vote down
Neon lamp dimmer0 vote up vote down
Microphone phantom power supply1 vote up vote down
AD9850 DDS daughterboard0 vote up vote down
30M PSK31 Transceiver circuit diagram1 vote up vote down
SOP receiver (PDF)0 vote up vote down
SOP direct conversion receiver0 vote up vote down
Popular Electronics Ultrasound Detector0 vote up vote down
PIC micro to ISA bus interface0 vote up vote down
Balanced microphone preamp2 vote up vote down
Machine Independent Parallel Interface0 vote up vote down
Navigator 555A radio direction finder (RDF) circuit diagram0 vote up vote down
Signal Tracer and Injector-1 vote up vote down
80188XL Engine Tachometer / Race Computer0 vote up vote down
TDS/PPM Meter for measuring of the amount of salts in a solution0 vote up vote down
Laser Modem with an Arduino Microcontroller0 vote up vote down
24" Wall Clock0 vote up vote down
Linuxstamp general purpose processor module based on Atmel AT91RM92000 vote up vote down
PG31 GPS RS232 GPS development board0 vote up vote down
PG31 GPS RS232 USB development board0 vote up vote down
PointLess LED Array - A 8 by 8 array displays something using POV0 vote up vote down
A "persistence of vision display" (POV display) using LEDs0 vote up vote down
PC to microcontroller communications using power from the PC serial port0 vote up vote down
RS232 RS485 USB Converter Board0 vote up vote down
PalmPilot turbo boost guage interface0 vote up vote down
1.5V iPod Microphone (PDF)0 vote up vote down
Inverter for fluorescent lights as published in Silicon Chip Magazine February 1991 (PDF)0 vote up vote down
Solar switching regulator as published in Silicon Chip Magazine January 1994 Part 1/2 (PDF)-2 vote up vote down
Solar switching regulator as published in Silicon Chip Magazine January 1994 Part 2/2 (PDF)-1 vote up vote down
LDR light/dark activated relay switch0 vote up vote down
Dual Voltage Controlled Oscillator w/Modulator1 vote up vote down
Spring reverb0 vote up vote down
MS Stereo Decoder0 vote up vote down
Drum percussion sensor schematics-1 vote up vote down
2 Note Ribbon Controller0 vote up vote down
4 Bit Digitizer / flash ADC using discrete components0 vote up vote down
Using the Hot Springs Reverb reverberation unit0 vote up vote down
midi2cv8 to Drum Tone Board Connections0 vote up vote down
Practical MS Decoder Circuit0 vote up vote down
Drum Tone Oscillators0 vote up vote down
Theremax Theramic Circuit Schematic0 vote up vote down
Touch switches0 vote up vote down
Vocal zapper-2 vote up vote down
Headphone monitor amp-2 vote up vote down
RIAA Equalized Stereo Phono Preamp0 vote up vote down
Theremin controller2 vote up vote down
Touch Switches0 vote up vote down
6090 digital decoder schematics0 vote up vote down
White LED circuits0 vote up vote down
Electroluminescent Receiver Kit includes circuit diagram0 vote up vote down
Receiver based on NE6020 vote up vote down
Build your own UFO Bino-Scope unit - upgrade binoculars to become a photosensitive bino-scope0 vote up vote down
Controlling your SLR Camera from an Ipod0 vote up vote down
Deriving power from Lego NXT motor port A0 vote up vote down
External power supply for Lego NXT0 vote up vote down
Color sensor circuit0 vote up vote down
Wire guidance sensor0 vote up vote down
GP2D12 distance sensor0 vote up vote down
Infrared lamp0 vote up vote down
Laser Target Finder Sensor0 vote up vote down
Lego compatible, compact rotation sensor0 vote up vote down
DC40 - 40M Direct Conversion receiver0 vote up vote down
SSB linear amplifier made from a bunch of 2N2218 transistors0 vote up vote down
Homebrew signal generator tunable from 3 to 30 Mhz1 vote up vote down
Simple Dual Band SSB Transceiver (20/40 meters)0 vote up vote down
PASCO scientific model SF-9211 stroboscope schematic (PDF)0 vote up vote down
Microchip PIC ICD (in-circuit debugger)-1 vote up vote down
Variety of circuits for RS232 to TTL Signal Conversion0 vote up vote down
Variety of circuits for TTL to RS232 Signal Conversion0 vote up vote down
Smooth, fast, strong and cheap stepper motor controller using a PIC micro0 vote up vote down
Tony Nixons Pocket Programmer (PIC)0 vote up vote down
Simple switching power supply0 vote up vote down
Selection of PWM driver circuits for electric DC motors0 vote up vote down
PicoWeb V5.1 (AT90S8515) tiny web server0 vote up vote down
RDS Encoder0 vote up vote down
Mass storage and printer interface for the FX-700P calculator0 vote up vote down
MP3 Player circuit schematic1 vote up vote down
Atmel 89C2051 In-Circuit Programmer Schematic0 vote up vote down
8051 Development System Circuit Board0 vote up vote down
8051 Development System Circuit Board0 vote up vote down
8051 Development System Circuit Board0 vote up vote down
50W audio power amplifier circuit diagram-1 vote up vote down
CCD linear image sensor to PC parallel interface0 vote up vote down
MIDI drum machine project0 vote up vote down
MIDI Drum Machine Analog Input Schematic-1 vote up vote down
Microprocessor using Xilinx FPGA0 vote up vote down
Arduindo based Appliance Remote Control0 vote up vote down
Online thermometer based on an Arduino0 vote up vote down
PS/2 Keyboard Or Mouse based on an Arduino0 vote up vote down
RFID Access Control System based on an Arduino0 vote up vote down
Oscilloscope / Logic Analyzer based on an Arduino-1 vote up vote down
Arduino Based Security / Automation Sensors2 vote up vote down
Arduino speech sythesizer0 vote up vote down
Arduino based Time-Lapse Camera Controller0 vote up vote down
Interfacing an LCD touch control panel to an Arduino0 vote up vote down
Vehicle Telemetry Platform based on an Arduino0 vote up vote down
Virtual USB Keyboard based on an Arduino0 vote up vote down
Arduino based water flow guage-1 vote up vote down
Water Tank Depth Sensor based on an Arduino-1 vote up vote down
Weather Station Receiver based on an Arduino and 433MHz RF receiver module0 vote up vote down
Temperature controlled based on AT89CX051-1 vote up vote down
Sallen-Key Active Butterworth High Pass Filter Calculator and circuit diagram0 vote up vote down
Sallen-Key Active Butterworth Low Pass Filter Calculator and circuit diagram0 vote up vote down
MIDI Pedalboard encoder circuit diagram and background information0 vote up vote down
Tone Filters for Electronic Organs (PDF)-1 vote up vote down
40m band direct conversion receiver0 vote up vote down
80m band direct conversion receiver-1 vote up vote down
AC Power Meter0 vote up vote down
Remote Motor Controller0 vote up vote down
Precision Frequency Marker1 vote up vote down
Simple Inductance Meter0 vote up vote down
Regenerative Short Wave Radio0 vote up vote down
Sleep Timer0 vote up vote down
Super VXO0 vote up vote down
Homebrew 20m CW Transceiver0 vote up vote down
Homebrew 30m CW Transceiver1 vote up vote down
Homebrew 40m CW Transceiver1 vote up vote down
Homebrew 6m SSB/CW Transceiver0 vote up vote down
Homebrew 6m DSB Transceiver0 vote up vote down
TV RGB signal output from a SVGA graphics card1 vote up vote down
High Precision GPS/TV controlled Reference Oscillator0 vote up vote down
u-Blox GPS receiver board0 vote up vote down
I2C LCD interface0 vote up vote down
TV based Receiver for a Standard Frequency Generator0 vote up vote down
FPGA Based ADS-B Receiver and Decoder0 vote up vote down
ADMS programming Cable for the Yaesu FT50, VX1 and VX50 vote up vote down
Radio Interface Box for the Motorola Radius GP3000 vote up vote down
PG4S programming Cable for the Kenwood TM-V7 and TM-G7070 vote up vote down
Laptop Computer Serial Port Power Booster0 vote up vote down
SPDIF RCA to (Optical + RCA) Adapter0 vote up vote down
136 kHz direct conversion receiver0 vote up vote down
Chebyshev / Butterworth filters0 vote up vote down
AFSK 1200 Modem based on PIC16C6200 vote up vote down
PicCon - Hidden Radio Transmitter Controller0 vote up vote down
Audible S-Meter0 vote up vote down
40 Segment LED S-Meter circuit diagram0 vote up vote down
Bi-Directional 2.4 GHz One Watt Amplifier-1 vote up vote down
Bi-Directional 900Mhz One Watt Amplifier1 vote up vote down
20 Watt GaAaFET Power on 2.3 GHz0 vote up vote down
1 Watt 2.3 GHz RF Amplifier Using a MRF20010 vote up vote down
One Watt 2.45 GHz Linear Amplifier using RF Micro Devices RF2126-1 vote up vote down
VCR Tuner Based RF Spectrum Analyzer Schematic0 vote up vote down
2.3 GHz Power Amplifiers0 vote up vote down
2304 and 3456 MHz Power Amplifiers0 vote up vote down
LCD frequency counter (PIC16F84)1 vote up vote down
AD9852 DDS schematic0 vote up vote down
High Frequency VCO Design and Schematics1 vote up vote down
Dopler RDF (radio direction finder) circuit0 vote up vote down
Biquad Active Bandpass Filter Schematic-1 vote up vote down
VFO from 2001 ARRL Handbook, page 17.740 vote up vote down
VFO from 2001 ARRL Handbook, page 14.200 vote up vote down
Various sound card interfacing circuit diagrams0 vote up vote down
Assorted relay control circuits-1 vote up vote down
Assorted computer interface circuits0 vote up vote down
Assorted digital circuits0 vote up vote down
Basic opamp circuits0 vote up vote down
Assorted LED circuits0 vote up vote down
Miscellaneous simple circuits0 vote up vote down
Assorted power source and control circuits1 vote up vote down
Assorted RF circuits-1 vote up vote down
Assorted telephone circuits (ring generator, in-use indicator, audio interface)-1 vote up vote down
PIC16F84 tone generator with source code0 vote up vote down
PIC16F84 tone generator0 vote up vote down
PIC16F84 tone generator (6-Bit)0 vote up vote down
14MHz SSB 10mW Transceiver0 vote up vote down
Decimal DDS Signal Generator0 vote up vote down
Apple II/II+/IIe IDE Drive Interface0 vote up vote down
Circuits to transmit and demoludate RF / video signals over fibre optic cable0 vote up vote down
Space invaders game using PIC microcontroller0 vote up vote down
High quality exponential VCA-2 vote up vote down
VLF radio receiver schematic1 vote up vote down
VLF Upconverter for Shortwave Receiver-1 vote up vote down
Accelerometer Schematic0 vote up vote down
Basic Vox Circuit1 vote up vote down
Build A 100Khz Crystal Calibrator0 vote up vote down
Build A Simple Rechargeable CMOS Battery0 vote up vote down
Variable Bandwidth CW Filter-1 vote up vote down
Simple electronic keyer0 vote up vote down
An Inexpensive Tone Encoder0 vote up vote down
Build A High Performance Voltage Regulator From Discrete Components0 vote up vote down
Thermal cooling fan controller0 vote up vote down
FM Morse Code Keyer0 vote up vote down
12 Volt Gel Cell Charger circuit diagram0 vote up vote down
Selection of Integrated Circuit Audio Amplifiers-3 vote up vote down
Improved PL tone decoder0 vote up vote down
Easy Morse Code Keyer Circuit-1 vote up vote down
Build A 10 Amp 13.8 Volt Power Supply1 vote up vote down
Adjustable Voltage Regulator using a 7805 or other fixed linear voltage regulator instead on LM3170 vote up vote down
5 watt, 80 meter QRP CW Transceiver0 vote up vote down
Simple electronic S meter0 vote up vote down
Audio Speech Processor0 vote up vote down
CW Tone Keyer0 vote up vote down
Potpourri of Transistor Audio Amplifier Circuits-1 vote up vote down
40 Meter, 5 Watt QRP Transmitter circuit diagram0 vote up vote down
Using Pass Transistors Beef Up Voltage Regulator current output-1 vote up vote down
R/C digital camera controller0 vote up vote down
Digital Call Sign Annunciator0 vote up vote down
R/C helicopter camera0 vote up vote down
Monitor output from Motorola Oncore GPS engine in HP Z3801A in GPS Disciplined Oscillator0 vote up vote down
16 Watt audio amplifier using pair of 8 watt LM383 audio amplifier chips-2 vote up vote down
8 watt amplifier circuit diagram-2 vote up vote down
Magnetic cartridge amplifier-2 vote up vote down
Electret mic amplifier1 vote up vote down
Audio preamplifier-6 vote up vote down
LM358 preamp circuit diagram1 vote up vote down
Sound detector circuit diagram-1 vote up vote down
Tone detector circuit diagram0 vote up vote down
Tone generator circuit diagram0 vote up vote down
Warbler siren circuit diagram0 vote up vote down
40khz IR Tester circuit diagram0 vote up vote down
555 timer 40khz IR Oscillator0 vote up vote down
Basic IR detector / emitter circuit diagram0 vote up vote down
Ultrasonic switch transmitter and receiver circuit diagram0 vote up vote down
12 volt battery monitor circuit diagram0 vote up vote down
12 volt power supply circuit diagram0 vote up vote down
5 volt power supply circuit diagram0 vote up vote down
Battery voltage monitor circuit diagram1 vote up vote down
LM3914 battery monitor circuit diagram-1 vote up vote down
Multiple voltage power supply-1 vote up vote down
Voltage doubler using a 555 timer1 vote up vote down
Voltage inverter using a 555 timer0 vote up vote down
Miniature FM transmitter circuit diagram0 vote up vote down
Sensitive FM transmitter circuit diagram0 vote up vote down
Simple RF transmitter circuit diagram0 vote up vote down
1.5 volt tracking transmitter circuit diagram0 vote up vote down
Tracking transmitter circuit diagram1 vote up vote down
Speech Amplifier Box-1 vote up vote down
Mini-MosFet Audio Amplifier-4 vote up vote down
Compact DJ station0 vote up vote down
Plant Watering Watcher (moisture meter)0 vote up vote down
Automated crib light circuit diagram1 vote up vote down
Sound pressure level meter circuit diagram0 vote up vote down
Sensor Electronic Tracker with H-Bridge Drive0 vote up vote down
Sensor Electronic Tracker with Simple Solar Charge Controller0 vote up vote down
Solar tracking control system-2 vote up vote down
LED7 solar tracker circuit diagram1 vote up vote down
Macrovision removal - includes circuit diagram and background information0 vote up vote down
Pressure Sensor-Based Altimeter Circuit1 vote up vote down
Build a good GaAs FET preamp for 2 meters, 222MHz or 440MHz0 vote up vote down
An Audio Limiter for NBFM use0 vote up vote down
Crystal heater / temperature stablization circuit (TXCO)-1 vote up vote down
An Audio-Noise-Based Voting Circuit0 vote up vote down
Low power audio amplifier circuit based on LM386-2 vote up vote down
LED dimmer circuit-1 vote up vote down
Build a DIY solar iPod charger0 vote up vote down
Virtual Game System - A game console with a mechanically scanned display0 vote up vote down
AVR Color Clock using RGB LEDs0 vote up vote down
PIC10F200-based electronic dice0 vote up vote down
PIC16F84-based video game system0 vote up vote down
Generate video signals in software using PIC0 vote up vote down
SX28-based color video game system0 vote up vote down
Generate composite color video signals in software using an SX microcontroller-1 vote up vote down
DIY Plasma Globe using an automotive ignition coil0 vote up vote down
DIY Power Pulse Controller0 vote up vote down
DIY Tesla coil - DC Powered with Plasma Output0 vote up vote down
Circuit diagram for connecting the SRF08/10/235 sonar modules to the BS2p Basic Stamp0 vote up vote down
Alphanumeric Led Display Project0 vote up vote down
H-Bridge Motor Driver Using Bipolar Transistors0 vote up vote down
Dual fan controller using ATTiny45 microcontroller0 vote up vote down
Standalone LED tester0 vote up vote down
DC Motor-Driver H-Bridge Circuit0 vote up vote down
Infrared Transmitter Project Implemented on a Solderless Breadboard0 vote up vote down
Model rocket launch controller0 vote up vote down
How to Make a PWM Circuit without a Microcontroller0 vote up vote down
How to Control LED Brightness with a PWM Circuit using a 74AC140 vote up vote down
Making an Amplified Color Sensor from an LED and an Op Amp0 vote up vote down
Schematic and breadboard layout for reversed LED color sensor using an opamp1 vote up vote down
Making a FRED photopopper0 vote up vote down
Simple switching regulator (experimental)0 vote up vote down
RS232 interfaced DVM using a PIC12F675 including source code for CCS C Compiler0 vote up vote down
A GPS receiver based frequency standard0 vote up vote down
Build a breadboard power module for integrated circuits0 vote up vote down
Speaker cabinet simulator - professional-quality frequency response in a DIY-friendly circuit0 vote up vote down
Two channel distortion circuit2 vote up vote down
Marshall 18W adapted for use as a distortion stompbox0 vote up vote down
Vox AC-30 Top Boost adapted for use as a distortion stompbox0 vote up vote down
Closer look at the FET booster based on a vintage Fender 12AX7 input stage.-1 vote up vote down
Ampeg SB-12 Portaflex adapted for use as a bass overdrive stompbox0 vote up vote down
Distortion effects using an LM386 audio amplifier IC1 vote up vote down
Two 9v battery-powered amps based on the LM386. Schematic and PCB/perfboard layouts.-1 vote up vote down
Matchless DC/30 adapted for use as a distortion stompbox0 vote up vote down
Treble Booster/Overdrive including a perf board circuit layout0 vote up vote down
Schematic of a Rockman-like distortion. Schematic and PCB/perfboard layouts.0 vote up vote down
Mr. EQ - a simple, yet potent DIY equalizer1 vote up vote down
New clipper circuit diagram (based on TL071 opamp)1 vote up vote down
Versatile FET booster engine. Schematic and perfboard/PCB layouts.0 vote up vote down
Peppermill overdrive - A simple, transparent overdrive. Schematic and PCB/perfboard layouts.0 vote up vote down
Faux-phaser circuit with LFO and manual (wah pedal) modes. Schematic and and PCB layout.0 vote up vote down
Fender Princeton adapted for use as a distortion stompbox0 vote up vote down
Ruby is an "enhanced" version of the Little Gem battery-powered amplifier (LM386 based design)-1 vote up vote down
Supro 16T adapted for use as a distortion stompbox0 vote up vote down
Dual parallel buffered effect loops with blend control. Schematic and perfboard/PCB layouts1 vote up vote down
Marshall 100W Super Lead adapted for use as a distortion stompbox. Schematic and PCB layout.1 vote up vote down
An ultra-flexible tonestack with clean boost. Schematic, photo, and PCB/perfboard layouts.0 vote up vote down
Tube Screamer-based overdrive. Schematic and PCB/perfboard layouts.1 vote up vote down
Umble - A distortion stompbox, inspired by Dumble amplifiers. Schematic and PCB/perfboard layouts.0 vote up vote down
Boogie MkI adapted for use as a distortion stompbox0 vote up vote down
Two Transistor Reflex Radio0 vote up vote down
LED flasher using 4584 hex inverting Schmitt trigger0 vote up vote down
Sound operated switch0 vote up vote down
Low power audio amplifier using BC109C along with BD679 and BD680 Darlington pairs-4 vote up vote down
Long duration timer using 4060 12-stage binary ripple counter0 vote up vote down
Infrared headphone system (includes transmistter and receiver schematics along with vero layout)1 vote up vote down
Simple stepper motor driver for PC parallel port0 vote up vote down
Optically isolated TRIAC driver0 vote up vote down
Reaction timer using 4013 flip-flop and 4060 12-stage binary ripple counter0 vote up vote down
10 watt audio power amplifier using discrete transistors (includes PCB layout)0 vote up vote down
TRIAC based lamp dimmer circuit diagram0 vote up vote down
Stroboscope0 vote up vote down
8049 Spy - read the internal ROM contents of a 8048 or 8049 processor0 vote up vote down
MS-DOS EEPROM Programmer0 vote up vote down
Fluke 8010 / 8012 Interface0 vote up vote down
6802 Nano computer0 vote up vote down
Nikon IR-Remote Control based on Atmel ATtiny130 vote up vote down
SAA1064 display module project0 vote up vote down
SB-Bus Drivers Introduction and Circuit Diagrams0 vote up vote down
AVR STK200/STK300 ISP Dongle circuit diagram0 vote up vote down
Tiny Eprom Simulator0 vote up vote down
UTP Cable Tester0 vote up vote down
PC based biofeedback monitor2 vote up vote down
Camera remote control system using Basic Stamp0 vote up vote down
Audio Detector Circuit1 vote up vote down
RF Modem Robotics Project-1 vote up vote down
Real-time Laser Range Finding Vision System0 vote up vote down
10Hz - 100KHz D.D.S. Function Generator0 vote up vote down
RS-232 to TTL cable0 vote up vote down
Very basic circuits0 vote up vote down
Implementing Infrared Object Detection0 vote up vote down
R2T2 Haywire Home Station0 vote up vote down
ICOM CI-V interface with RS232 RTS to PTT0 vote up vote down
Bat detector0 vote up vote down
30-Meter QRP Transmitter for Morse Code0 vote up vote down
3rd brake light circuit diagram0 vote up vote down
DC to AC inverter using a 555 timer1 vote up vote down
555 Timer IC Tester circuit diagram1 vote up vote down
555 go / no-go tester circuit diagram0 vote up vote down
Dual (postive and negative) 12V power supply1 vote up vote down
Active Antenna AA-7 HF/VHF/UHF, 3-3000MHz0 vote up vote down
Active antenna 1 to 20dB, 1-30 MHz range0 vote up vote down
Active Antenna for AM-FM-SW0 vote up vote down
FM radio active antenna0 vote up vote down
Light / dark activated relay0 vote up vote down
Touch activated alarm system0 vote up vote down
Current booster for 78nn series voltage regulators0 vote up vote down
Aviation band receiver-1 vote up vote down
Car backup / reversing alarm1 vote up vote down
12V Lead-Acid Battery Monitor using LM39141 vote up vote down
Battery Tester for 1.5 and 9V-1 vote up vote down
Charger for gel lead acid batteries0 vote up vote down
Broadcast-Band RF Amplifier0 vote up vote down
Bug detector with beep using 7413 or 74LS130 vote up vote down
Bug detector / countersurveillance monitor0 vote up vote down
Electronic canary doorbell0 vote up vote down
12V to 9V car coverter circuit diagram0 vote up vote down
Clock generator0 vote up vote down
Continuity tester V2 circuit diagram0 vote up vote down
Continuity tester circuit diagram0 vote up vote down
Coin tosser0 vote up vote down
Compressor-mate power protection for refrigerators, freezers and air conditioners1 vote up vote down
Cut phone line detector0 vote up vote down
DSL / ADSL phone line filter0 vote up vote down
Waterpump Safety Guard for fish pond / fish tank0 vote up vote down
Third brake light pulser circuit0 vote up vote down
Miniature FM Transmitter #1-1 vote up vote down
Miniature FM Transmitter #20 vote up vote down
Miniature FM Transmitter #3-1 vote up vote down
4-transistor transmitter circuit diagram0 vote up vote down
FM telephone transmitter0 vote up vote down
Electronic dazer0 vote up vote down
High voltage DC generator-1 vote up vote down
High-Voltage Pulse Generator0 vote up vote down
Jacob's Ladder0 vote up vote down
Lightning bulb - Create an electrical storm in a light bulb0 vote up vote down
Negative Ion Detector-1 vote up vote down
Negative Ion Generator0 vote up vote down
Tesla coil0 vote up vote down
Solid state tesla coil0 vote up vote down
High voltage zappers0 vote up vote down
Motorcycle battery charger0 vote up vote down
Lamp flasher/dimmer0 vote up vote down
Miniature tracking transmitter0 vote up vote down
Motorcycle low battery voltage warning circuit-1 vote up vote down
Morse Code Practice Keyer 10 vote up vote down
Morse Code Practice Keyer 20 vote up vote down
Motorcycle brake light flasher1 vote up vote down
Motorctcle turning signal system-1 vote up vote down
Automatic 9V NiCad battery charger0 vote up vote down
9-pin null modem cable0 vote up vote down
Audio preamp2 vote up vote down
Logic probe0 vote up vote down
Pulse width modudulator using 555 timer IC0 vote up vote down
Active Power Zener0 vote up vote down
Sound activated relay, V10 vote up vote down
Sound activated relay, V20 vote up vote down
Basic RF oscillator0 vote up vote down
Light sensing RF transmitter0 vote up vote down
ScanMate audio activated recorded0 vote up vote down
Subcarrier adapter to listen to hidden subcarrier signals on FM radio1 vote up vote down
Water-level sensor0 vote up vote down
741 Light Sensor-1 vote up vote down
Fluid level detector1 vote up vote down
Solid state relay circuit0 vote up vote down
Simplest R/C circuit0 vote up vote down
Theremin-1 vote up vote down
Touch switch using transistors0 vote up vote down
1.5V tracking transmitter circuit diagram-1 vote up vote down
Micro-Spy with FETs1 vote up vote down
Micro-Spy with USW0 vote up vote down
Micro-Spy with TTL0 vote up vote down
Wailing alarm siren0 vote up vote down
Wireless microphone0 vote up vote down
Christmas lights tester0 vote up vote down
555 Timer Tutorial + Circuits0 vote up vote down
Car Nicad charger0 vote up vote down
NiCad Discharger for Tx & Rx Packs0 vote up vote down
Glowplug driver for radio control models0 vote up vote down
Lead acid battery charger with float0 vote up vote down
Simple constant current source0 vote up vote down
Solar cell Nicad charger using Maxim MAX6392 vote up vote down
Two tone train horn0 vote up vote down
Low cost Atmel in-system programmer0 vote up vote down
Ultra low-cost programmer for AT90S family0 vote up vote down
AVR (AT90S2313) composite PAL colour bar generator-1 vote up vote down
Connecting AT90S2313 with LCD display 2x16 char and 4x4 keypad0 vote up vote down
Electronic safety lock based on ATtiny260 vote up vote down
Greek telecard reader0 vote up vote down
128x64 LCD Driver for AT90S2313 (ZIP file)0 vote up vote down
1-Wire Barometer project0 vote up vote down
Simple pH Meter Circuit, A Low Cost Adapter for Your Digital Voltmeter-1 vote up vote down
Connecting LED to PIC Micro I/O pins (PDF)-1 vote up vote down
FCTS Project0 vote up vote down
Heart rate sensor-2 vote up vote down
Motor walker circuit0 vote up vote down
Zener-based solar engine0 vote up vote down
Morse Code Beacon Keyer-1 vote up vote down
PC Automatic Power-on Circuit0 vote up vote down
Constant Temperature Circuit0 vote up vote down
Improved FM Stereo Modulator0 vote up vote down
Count Accumulator for Radiation Levels (CARL)0 vote up vote down
Modifications for CDV700 Geiger Counter0 vote up vote down
40-30 CW Transmitter (Tube based)0 vote up vote down
The WB0RIO 6U8A Code Practice Oscillator0 vote up vote down
The House Finch Direct Conversion Tube Receiver-1 vote up vote down
The Little Chickadee 6U8A QRP Transmitter0 vote up vote down
Magic Eye Tube Wavemeter0 vote up vote down
WB0RIO Piglet 6U8A Regenerative Receiver (Tube based)0 vote up vote down
QRP Antenna Tuner0 vote up vote down
All-Ears QSK Timing Generator-1 vote up vote down
Smooth Tone Clickless CW Sidetone Generator0 vote up vote down
Power Supply for Vacuum Tube Experiments0 vote up vote down
Regulated 12V Dual LED Lamp-1 vote up vote down
Regulated Dual 3 Watt White LED Lamp0 vote up vote down
Regulated 24 Watt Broad Spectrum LED Lamp0 vote up vote down
Lightning activated camera shutter trigger0 vote up vote down
TTL Pulse Reading Logic Probe0 vote up vote down
High Fidelity FM Stereo Modulator (Rev E2)0 vote up vote down
VXO FM Bug0 vote up vote down
Big Ear Stereo Parabolic Microphone0 vote up vote down
Ultra Low Power LCD Indicator0 vote up vote down
13 Color LED Rainbow circuit schematic-1 vote up vote down
Nine Volt Battery Eliminator1 vote up vote down
Arduino LFO Waveform Generator V20 vote up vote down
Vacuum Tube B+ Delay Circuit0 vote up vote down
Hammonator Organ to Guitar Amp Conversion (tube amplifier)-2 vote up vote down
Lil' Tiger Hammond AO-43 Organ to Guitar Amp Conversion0 vote up vote down
Liquidator Tube Phaser/Chorus Effect0 vote up vote down
Voltage Controlled Panner0 vote up vote down
Guitar Reverb Effect Version 20 vote up vote down
Stereo Audio Isolator0 vote up vote down
Panner Waveform Generator0 vote up vote down
Voltage controlled audio panner0 vote up vote down
Isolated Telephone Interface (phone tap) for tape recorder, PC sound card etc-1 vote up vote down
PWM DC Motor Speed Control0 vote up vote down
PWM Motor Speed Controller / DC Light Dimmer2 vote up vote down
PWM Motor/Light Controller circuit diagrams0 vote up vote down
Microprocessor RS-232 Reset0 vote up vote down
18 LED dimmable LED lamp circuit diagram0 vote up vote down
Regulated Dual White LED Lamp0 vote up vote down
Seven Component Regulated LED Lamp0 vote up vote down
Buck Mode Switching Regulator for Solar Applications0 vote up vote down
12 Volt Battery Voltage Monitor (kit available)0 vote up vote down
Solar Panel Charge Controller / Low Voltage Disconnect Circuit-1 vote up vote down
Solar Panel Charge Controller / Low Voltage Disconnect Circuit (SPC1)0 vote up vote down
12 Volt 10 Amp Dark Activated Switch (kit available)0 vote up vote down
DAS1 - 12 Volt 10 Amp Dark Activated Switch0 vote up vote down
High Efficiency 12V White LED Driver0 vote up vote down
12 Volt Differential Temperature Controller0 vote up vote down
Solar Panel Current Meter0 vote up vote down
LED Mood Light0 vote up vote down
Battery Low Voltage Beeper0 vote up vote down
12 Volt 15 Amp Low Voltage Disconnect (kit available)0 vote up vote down
Remote Solar LED light-1 vote up vote down
PWM Motor Speed Controller / DC Light Dimmer0 vote up vote down
PWM Motor Speed Controller / DC Light Dimmer0 vote up vote down
PWM Motor/Light Controller-1 vote up vote down
SCC2 10 Amp Solar Charge Controller1 vote up vote down
SCC2 10 Amp Solar Charge Controller1 vote up vote down
12 Volt 20 Amp Solar Charge Controller (kit available)0 vote up vote down
12 Volt 20 Amp Solar Charge Controller-1 vote up vote down
Shunt-mode Solar/Wind Charge Controller1 vote up vote down
Solar Powered Night Light0 vote up vote down
Solar Charged LED Flashlight0 vote up vote down
Self Powered Solar Box Furnace-1 vote up vote down
SPC2 6 Amp Solar Power Center0 vote up vote down
9 Amp in / 10 Amp out Solar Power Center (kit available)0 vote up vote down
SPC3 9 Amp in / 10 Amp out Solar Power Center1 vote up vote down
Solar Powered Reading Lamp-1 vote up vote down
12 Volt Toilet Tank Refiller circuit diagram0 vote up vote down
Low Power LED Voltmeter1 vote up vote down
WGR1 - 12 Volt Wind Generator Regulator0 vote up vote down
Expanded Scale Battery Volt Meter0 vote up vote down
Stereo Test Tone Generator0 vote up vote down
Octopus Curve Tracer0 vote up vote down
Temperature Controlled Nicad Charger-1 vote up vote down
12V, 4-AA Cell Differential Temperature Charger0 vote up vote down
Motorized Video Camera Mount-1 vote up vote down
Morse Code Beacon Keyer0 vote up vote down
Constant Temperature Circuit0 vote up vote down
Lightning Activated Camera Shutter Trigger0 vote up vote down
Pulse Reading Logic Probe0 vote up vote down
Micro Power FM Broadcasting Circuits0 vote up vote down
Voltage Controlled Panner1 vote up vote down
PWM DC Motor Speed Control0 vote up vote down
Guitar Reverb Pedal0 vote up vote down
AA battery solar charger0 vote up vote down
Solar Panel Charge Controller / Low Voltage Disconnect Circuit1 vote up vote down
Solar Panel Current Meter0 vote up vote down
LED Mood Light0 vote up vote down
PWM Motor/Light Controller0 vote up vote down
PWM Motor/Light Controller variants-1 vote up vote down
Low Power LED Voltmeter0 vote up vote down
Temperature Controlled NICD Charger0 vote up vote down
Circuit for interfacing a relay / solenoid to a PC based on a 2N7000 FET0 vote up vote down
Variety of receiver converter projects0 vote up vote down
One transistor FM receiver0 vote up vote down
42 Mc Band to 88 Mc Band (retrofit converter) Project-1 vote up vote down
RF noise bridge for HF0 vote up vote down
LC meter with LCD display for readout0 vote up vote down
160m mini portable End Fed Half Wave Tuner - MkII0 vote up vote down
RF/SS Handie Hopper Transmitter Schematic0 vote up vote down
AT90S8515 experimenter board0 vote up vote down
DIY shutterglasses controller0 vote up vote down
Stop Action 3D-Photography using an audio flash trigger0 vote up vote down
Remote control uses an IR receiver chip to receive the IR signal from the remote0 vote up vote down
How to construct Garmin GPS receiver interface cables0 vote up vote down
Vacuum Tube Microphone Preamp0 vote up vote down
FCD (Fuel Cut Defencer)0 vote up vote down
Jasmin floppy disk controller schematics-1 vote up vote down
Weather station with pressure reading, relative humidity, indoor & remote temperature reading0 vote up vote down
Battery Charger Ideas0 vote up vote down
Crystal radio circuits including diode performance comparison-1 vote up vote down
Game Show Timers0 vote up vote down
Induction receiver for tracing wiring behind walls, hearing lightning and other electric discharges0 vote up vote down
Refrigerator Door Alarm0 vote up vote down
Rain alarm / rain detector0 vote up vote down
Homebuilt video digitizer Mark I-1 vote up vote down
Homebuilt video digitizer Mark II2 vote up vote down
Daisy MP3 player project0 vote up vote down
Simple open source MP3 player with SD/MMC memory card support0 vote up vote down
Archery timer0 vote up vote down
Windmill DIY Analog MPPT (maximum power point tracker) Circuit0 vote up vote down
CO2 controller for planted tanks1 vote up vote down
Ultrasonic Distance Measurement With the MSP430 (PDF)1 vote up vote down
Texas Instruments collection of differential op-amp circuits (PDF)1 vote up vote down
Texas Instruments collection of buffer op-amp circuits for ADC0 vote up vote down
Simple MPPT-Based (maximum power point tracker) Lead Acid Charger Using bq2031 (pdf)0 vote up vote down
Wireless local network for PalmPilot (large PDF)0 vote up vote down
FET Preamp Cable-3 vote up vote down
Building a Hardware Random Bit Generator0 vote up vote down
Monostable multivibrator0 vote up vote down
Altec 1564A Preamp Power Supply1 vote up vote down
Neumann U67 microphone preamp power supply-3 vote up vote down
Midibox 640 vote up vote down
TTL to RS232 adapter using 2N3906 / 2N3904 transistors0 vote up vote down
VK5JST Aerial analyser0 vote up vote down
An Ultra Low Distortion Audio Test Oscillator0 vote up vote down
A dummy load and power meter for HF (PDF)0 vote up vote down
An ESR Meter For Electrolytic Capacitors (and Low Ohms Meter)-2 vote up vote down
20 amp (peak) power supply for SSB transceivers0 vote up