Wanted to make a silent super efficient implementation so have done PCB with:
- mains → 3v3 module. (keeps esp32 powered efficiently)
- Instead of relay its driving a triac to turn on external supply.
- The output signal for leds is optically isolated from esp32 and gets its 5V from the 12V external supply.
The reason for doing the isolation was to not have the gnd of external supply connected with esp and also to allow for potential daisy chain setup. A signal can be passed through and have different sets of strips powered separately without having gnd loops and other issues cropping up.
The mains->3v3 is kind of pricy (~£5) but the other components are fairly low cost
Triac switching circuit ~80p which is pretty nice for a solid state solution.
I currently don’t have a heatsink on it and need to see how that copes with higher current loads.
I only built it up tonight so will do some standby power tests and see how it copes under load.
Video in operation