"push" physical button on a remote

Question

I have a remote for my kitchen fan where I can turn on the fan and toggle to light. This remote says on the back to be using 433MHz so I bought a receiver and transmitter for my Raspberry Pi in hopes of sniffing the signal and using the Pi to send the signal. This didn't work at all as I couldn't sniff the signal. I couldn't see anything change in piscope either when clicking the buttons.

So now my next project is to connect the remotes buttons to my Pi and simulate a push using the GPIO pins somehow.

I'll attach a picture of the remote at the bottom.

I'm only interested in toggle the light and that is the button furthest down on the PCB.

I'm kind of a noob when it comes to electronics so I have a couple of questions. The remote is powered by 1x AAA batteri thus using 1.5V What is the best way to power the remote in this situation? To use the battery or connect it to the Pi?

And how would I simulate a button press? I read somewhere about removing the button and solder on a optocoupler instead and use that to trigger a button press.

Are there any other methods that are more suitable?

Answer 1

The remote is powered by 1x AAA batteri thus using 1.5V What is the best way to power the remote in this situation? To use the battery or connect it to the Pi?

You could power the remote from the Pi by splitting the 3v rail in half with a potential divider to generate the required 1.5v but I'd be wary of the current drawn by the remote when transmitting. You might be better keeping the battery, that way you can still use the remote manually when the Pi is turned off.

I read somewhere about removing the button and solder on a optocoupler instead and use that to trigger a button press.

You could but if you're look for a simpler way I'd suggest finding a HAT for your Pi with some relays on it and use these to duplicate the button press:

^{simulate this circuit – Schematic created using CircuitLab}

This way you can keep the button in place and only minor soldering is required, you may even be able to just wrap the bare ends of the wires around the button legs.