All 2692 schematics are available on a single page here.

Data acquisition (DAQ) and data logging circuit diagrams / circuit schematics

• Acceleration Sensor Network
  
• Making an LM35 temperature recorder (based on PIC12F675) - logs to EEPROM
  
• Making an LM35 temperature recorder (based on PIC12F675) - serial output
  
• Connect a NTC with a wheatstone bridge to a normal AD-Input
  
• Accelerometer with microcontroller and display
  
• Using a 555 Timer as an A/D converter
  
• Transducer Amplifiers
  
• Strain gauge sensor interface
  
• 1-Wire Barometer project
  
• ADXL202 break-out board
  
• ADC logger 6ch Measurent and serial port logger with wireless longrange link
  
• Atmel Mega32 8ch Analog signal measure logger
  
• Water-level sensor
  
• Serial Port A/D-converter
  
• Centronics port D/A converters and low-pass filter
  
• Honey Bee counter (PDF)
  
• Capacitance type liquid level measurement (PDF)
  
• Analog input section based on AD9220
  
• Ultrasonic Range Finder & Imager
  
• Ultrasonic range finder circuit
  
• Addressable ADC
  
• Accelerometer Schematic
  
• Thermostat node schematic
  
• Self made data-logger V2.5 (second edition)
  
• Pressure Sensor-Based Altimeter Circuit
  
• Home Brew Compass Sensor
  
• Precision Digital Altimeter
  
• Remote digital thermometer sends data over AC power line
  
• Voltage follower with 1G ohm input resistance
  
• 8 Photo-Detector Circuit Board
  
• 4 Bit Digitizer / flash ADC using discrete components
  
• Simple device for connecting serial instrument with RS485 or RS232 to the internet
  
• Simple RS422 Converter for Minilogger
  
• Data Acquisition System using ATmega8
  
• Data Acquisition & Logging System Using AT89c51 and Visual Basic
  
• Low cost gyro / accelerometer combo sensor
  
• Wind speed logger
  
• Wind speed logger Mk2
  
• Circuit monitoring device logs for over 10 days and can log up to 32k events both digital and analog
  
• Online thermometer based on an Arduino
  
• Arduino based water flow guage
  
• Water Tank Depth Sensor based on an Arduino
  
• Weather Station Receiver based on an Arduino and 433MHz RF receiver module
  
• PIC16F877A Thermometer with MCP9700A sensor
  
• ADC Input Driver DIFFERENTIAL to DIFFERENTIAL
  
• ADC Input Driver DIFFERENTIAL to SINGLE-ENDED
  
• ADC Input Driver FULLY DIFFERENTIAL AMPLIFIER
  
• ADC Input Driver SINGLE-ENDED to DIFFERENTIAL
  
• ADC Input Driver SINGLE-ENDED to SINGLE-ENDED
  
• Data Acquisition System using ATmega8
  
• Pyranometer to Current Converter