Check out my growing DIY projects blog at:
http://electronicsandbeer.blogspot.com/
This is my first working multi-module prototype.
Mode of operation:
Infrared emitters for one pixel turn on for about 100 microseconds, then an analog reading is taken, then the IR emitters are turned off. Then the controller goes to the next pixel and repeats until it has cycled through the 4 pixels. It does this cycling through the 4 pixels around 30 times per second. The current pushed through the IR emitters is 140 mA, but since the emitters are on for only a short period of time, the average current consumption of the IR emitters is only a couple percent of the full current, so more like 3-4 mA.