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High resolution PC parallel port ADC
This ADC is based on a MAX132 and has a resolution of 18 b plus sign (2 µV LSB !) at 16 samples/s, with four differential or eight single-ended input channels. It is based on the Maxim application note "PC printer port controls data logger" (search the Maxim site for the original article). Like for the previous ADC, a simple C program for Linux which computes the acquisition time and the mean values and variances for the four channel readings is included in the tar file below.
Here is the complete ADC schematic (click on the image to enlarge):
Bill of materials
Download the complete tar file (33 kB) with the schematic, BOM, description and some sample code to test the ADC.