>> if you spun the knob too quickly, it would actually end up going backwards The spinner on arcade Tempest can do the same. IIRC the quadrature signals feed t

>> if you spun the knob too quickly, it would actually end up going backwards The spinner on arcade Tempest can do the same. IIRC the quadrature signals feed the clock and direction pins on a 4 bit up-down counter on the board, and software probably polls the counter. If you spin it fast enough (I used Teflon spray on mine) you could wrap the counter around and get it to move backwards. Something like that, it's been a few years...