I spent several hours last night working on the firmware for the bloom lights. I quickly ran into a strange, frustrating problem: every attempt at smooth animation rapidly became choppy, lights flickering and stuttering. I found some demo programs for the TLC5940 LED-controller chips, and they ran perfectly. I disabled one of the two chips, driving only 16 channels, and that ran perfectly. I dug through the driver, wrote a simple bit-bang replacement, quickly ran into the same problem: what??

Several hours of debugging later, the problem turned out to be purely analog. The bloom light has 120 LEDs divided into 30 channels, each drawing 20 milliamps: that is, 600 milliamps altogether. The control circuit runs at 5V, regulated down from 12V by an LM7805. And…. the power supply is a plain ol’ wall-wart, rated for 1 amp. So I’m just drawing more power than it wants to supply, and the voltage is dropping, and havoc ensues.

Ok. New 4-amp 12V supply on the way. Ridiculous LED illumination will be mine! Muahahaha.

[p.s.: 4-amp supply applied. Smooth, beautiful LED fading resulted. Yeah!]