I'm trying to design an input circuit for a microcontroller that will work with 1-10 V dimmers. There appear to be two standards for dimmers, current source and current sink, and I'm trying to work out if I can create a system that will work with both.
As I understand it, most domestic lighting uses current sink dimmers: the controller or ballast provides the current with a 10 V or more signal and the dimmer reduces that signal.
There is also a standard from theatrical lighting, where the dimmer provides the voltage and current and the controller just measures the voltage level.
I've designed my circuit as a current source using an LM334 plus a Zener diode to turn the supply voltage of 12-14 V into a current source that will float up to 11 V. A potential divider, crude low pass filter and 3.3 V Zener diode convert the signal into 0-3.3 V for an analogue to digital converter.
First question. Did I do anything wrong here or is this workable? It seemed OK when I breadboarded it.
Second question. It would be great if this worked or automatically adapted to the two different standards. Can this circuit be adapted to work with a 0-10 V current source input signal?