This project is a simple 12-bit, 8-channel analog to digital converter (with 4 additional digital inputs), which may be connected to the PC through the serial interface (RS232). The sequence of sampled channels, and sampling frequence are programmed by the PC while the maximal sampling frequency is limited by the data transmission rate, and at 115200 baud is equal to ca. 3kHz for 1 channel without digital inputs, and to ca. 500 Hz for 8 channel with digital inputs.
The analog input voltage range is -2.5V to 2.5V. The digital inputs may be used for recording additional digital signals, eg. the time code used to synchronize the recorded data with other events. The project is based on PIC16F84 (or 166C84) microcontroller, and MAX190 (or MAX191) ADC. The device is mounted on a small single-sided printed circuit board, easy to prepare even at home.
PIC16F84 12-bit, 8-channel analog to digital converter: [Link]