You could use a digi-cam to generate a snapshot, and have a program scan through a bitmap looking for the matrix and holes in the matrix. This would be easier if on a PC.

<>< Lance.



steve Taylor wrote:
Well you can just watch the volts and current through the diodes, but I have experienced LEDS that still diode but don't glow. I would like to actually sense light from each pixel of the grid. A photo-diode is pretty cheap, but how the hell do you read 350 of 'em cheaply I wonder !
Steve