...always under very slow construction.
Here you can find some of the circuits I have built in the past, in particulare a 12 b and 18 b parallel port analog-to-digital converters with complete schematics and C source code for Linux
This simple PC parallel port ADC has 12 b resolution, four differential input channels and is it's quite fast; the chip itself (MAX186) is able to go up to 133 ksamples/s, but the actual speed will be determined by the software used. I wrote a simple C program to test the ADC with Linux; it acquires a selectable number of samples (default 1000 samples for every channel) and computes the acquisition time and the mean values and variances for the four channel readings. Tested on a PC with a 333 MHz AMD K7 processor this circuit had a throughput of about 2.5 ksamples/s
Schematic (22 kB PNG image)
Bill of materials
Download the tar file (47 kB) with schematic in PNG format, BOM, circuit description and some C code to test the ADC using Linux.
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.
Schematic (22 kB PNG image)
Bill of materials
Download the complete tar file (33 kB) with the schematic, BOM, description and some sample code to test the ADC.
