I am in the process of designing an illuminated beer pong table. What I want it to do is detect when a cup is on top of a "pixel" or off it and then display a red or green led underneath a piece of frosted plexiglass depending on the above circumstance. I also want it to "restack" the group of 10 cups once it detects a certian number of empty cups. My detector is going to be an IR LED and a photodiode.
I can handle the programming just fine but the wiring is kind of a new game to me. I know I can use a single ground for one set of ten "pixels." But I have too many connections to pins in my diagram than arduino has pins on the board.
So from what I can conclude I need an always on connection for my IR LED and Photodiode but still be able to take a reading from the photodiode. And I need two pins per "pixel" for my red and green LED's and I have a common ground for everything. That brings my total for ONE side to 41 pins. Arduino only has 54 and I really don't want to use 2 Arduino's( 1 for each side).
Is there anyway I can reduce the number of pins I need per "pixel" ??? Any help would be greatly appreciated seeing as I am a newb.
sorry for the shitty paint overlay on my nice autocad diagram.