Yeah so you’d probably just be grounding the positive side of the button momentarily. I’m pretty sure I did that with a ducted heater remote once, if it’s 3.3 you can just attach it to a pin from your board, then send the pin low to press. 5v you might want a level shifter in between. Have you used esphome before/do you have home assistant? Then you can automate the press to a motion sensor or widget on your phone.

You need electrical experience, I wouldn’t recommend anyone to work with high voltages unless they knew what they were doing. The method depends on the device, every one is different. For the aircon unit the esp is an internal remote, so I spent time decoding that model’s IR codes and building a platform for reliable control via home assistant. I have fans around the house that use mains voltage motors with 3 speeds, those got an interlocked 3 channel relay board. The ice maker used digital logic, so the esp sits between the control board and the rest and intercepts button presses to keep track of state and the injects its own commands for remote control(not my work). If you are lucky there will be a guide on the internet you can apply to your specific device, otherwise you’ll have to work the project out solo from smaller guides.

Yeah home built and programmed smart devices are the way to go. I’m addicted to the rush of making dumb appliances automated.

The smartphone controlled aircon for $150 extra? Slap a $4 Esp in that. $400 to get sleek control of your central heating? $4 Esp. Turn on the ice maker on the commute home? You guessed it, $4 Esp.

Yeah it’s good.

not carnelian? was so close

Nahh it was renamed to 365 Cupilot