Detecting 24V AC with an ESP32

This is a simple 24VAC detector using an ESP32 microcontroller, an SFH620AGB optocoupler, and a 10K resistor. When I cranked up the sample rate, I saw the expected 120 Hz oscillation.

I got the idea from https://electronics.stackexchange.com/questions/348962/how-to-drive-optoisolator-from-mains, though 20-30VAC is less scary than mains voltage.

The toroidal transformer is a Vigortronix VTX-146-030-212.

Видео Detecting 24V AC with an ESP32 канала Paul M