Ok, well if I am going to scrap the max7313s, I'd like to come up with a better way to handle the IR sensors. Right now I've been just treating the output of the phototransistor as a digital input, and tailoring the pull up resistor to get the sensitivity that I want. But this doesnt work very well as I'm throwing away alot of info and its very picky about different types of glass, etc...
I'd like to find a way to cheaply multiplex the analog sensors to available A/D pins on the PIC. Currently I was planning on 128 IR sensors but I am considering increasing this to 256.
What if I were to multiplex the IR leds the same way, and then feed all of the IR sensors back to a op-amp summer and then I will just assume that whatever signal I get from the opamp is coming from the only device with an active IR led... Wont be perfect, but it should work well enough. What do you think? Can you suggest an adequate (and cheap) opamp?