Is this a good time to ask about a project I would like to do?
I have two 220v heaters in my garage, one on each floor. I'd like to turn one or both of them on from my phone. I'd also love temp sensors near each of them.
So far I haven't found a good FOSS option to control a 220v 40A relay. Any suggestions what to use or how to set it up would appreciated.
Use something like an Aube RC840T-240; it generates an isolated 24vac supply and has an isolated normally-open 24vac input for closing the contactor. Using anything else is liable to cause life-threatening spiciness if something goes wrong.
I use one for my addition's electric baseboard heat, and control it with a standard dry contact thermostat, but you could easily use a mosfet or relay controlled by an ESP32 or similar instead.
Some completele unrelated nitpick: you wrote "220v".
As a rule of thumb: any physical unit derived from a real persons name is not written in lower case. In this case, the unit honors https://en.wikipedia.org/wiki/Alessandro_Volta and so it's written "220 V" instead.
Applies to other units based on surnames, like Heinrich Hertz' "Hz", Lord Kelvin's "K", James Watt's "W", André-Marie_Ampère's "A" and so on.
I have two 220v heaters in my garage, one on each floor. I'd like to turn one or both of them on from my phone. I'd also love temp sensors near each of them.
So far I haven't found a good FOSS option to control a 220v 40A relay. Any suggestions what to use or how to set it up would appreciated.