re wanted a to d hardware for a pc in ncr mpd ftcollinsco ncr com brad wright writes if you know much about pc s ibm comp you might try the joystick port though i haven t tried this myself i ve been told that the port has built in a d converters this would allow the joystick to be a couple of pots if you could find the specs this might just work for you i believe that the a d converters found on a joystick port are really timers that tick off how long it takes an r c circuit the r being your paddle to charge up to something like vcc for games this works pretty well but you certainly wouldn t want to try to take lab measurements off something as non linear as that hmm i suppose you could linearize it in software but the real problem is that the precision of your measurement is no longer constant higher voltages would be more precise on the other hand i could be wrong and perhaps the game card designers splurged for the extra to make a cheap constant current source out of an op amp but i wouldn t expect that joel kolstad
