I want to use a rf pwm dimmer that only works at 12v (~8-13v range when measured using a dc voltmeter), as an analog input to an arduino. This will be used to dim several buckpucks attached to digital outputs. I understand some kind of voltage division is necessary.
Its for a backup led light system, and the dimmer will be powered by a stable 12v dc, provided by a sepic converter (since the sla will kick out anywhere from 11-14v). Now, keeping this as simple as possible, can i just use a pot on the output of the dimmer to bring the output down to 5v, while keeping a linear 0-5v range to use as an input to the arduino?
Well, i just tested this with a 1k ohm pot, and it seems to work fantastically. I adjusted it to kick out 0-5v on the pot center pin to the 0-5 ref, ground and positive are attached to the 12v out on my rf dimmer, and the ground for the pot is wired to led - on the buckpuck. All i need to do is wire the pot output to the arduino input, and i can use that to scale the pwm output on the digital arduino outputs. Pretty simple
One question though, for the 0-5v ref out, coming from the pot center pin to the arduino analog in, do i need to ground the pot ground to the arduino instead of led - on the buckpuck, or both? What pin if so?