The dimmer circuits (next chapter) are controlled by an adjustable voltage for each color. This voltage should be “remembered” even if the AC power is turned off completely with the wall switch. While it is possible to store these voltages (or a digital equivalent) in non-volatile memory, I chose a low-tech approach using motor-controlled potentiometers.
The drive motors are small DC gear motors controlling the potentiometers such they travel from end to end in about eight seconds. This is truly a set-and-forget arrangement.