I have a wireless garage door remote and looking to turn it into a wifi opener.

I am looking for something to act as a switch.

I was hoping i could connect a wire to 0v side of the switch and feed it 3.3v from the PI but manually doing it to the opener doesn't seem to give the desired result.

bridging a wire across the switch terminals does though.

so im needing a relay of some sort. i have read about relay boards, not sure how many "relays" i can operate from the board?

i need a minimum of 4 preferably 5 I was hoping to run it on a model A or Zero but neither have an ethernet port.

i did also read about being able to add an ethernet port using the SPI pins but am i still able to add the relay board provided i have enough pins? and not have an issue with lack of power?


Connecting unknown electronic devices to the Pi (or anything else) is fraught with difficulty.

There is NO WAY the Pi can "short out the pin".

You may be able to drive a transistor or MOSFET to simulate a button press. This requires at the minimum a common ground connection.

The only SAFE way is with an opto-isolator or relay.

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  • i guess "short out the pin" was poor wording i have added my edited comment above – B- Man Mar 5 '18 at 12:19
  • I think an npn transistor will work but unsure how to select what one? – B- Man Mar 6 '18 at 5:50
  • now knowing a little more about electronics since tinkering with a few other things i probably would build it with an opto-isolator on a circuit board rather than solder a few wires and transistors together – B- Man Oct 15 '18 at 9:37

I ended up soldering NPN transistors to the roller door remote either side of the manual switches. the base of the transistor had a 1k resistor that was attached to my PI GPIO pins. i made a common ground from the remote to the ground GPIO pin

then created a script to turn the gpio pins on for 1 second then back off.

works a treat!

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I have done this with a remote power point controller. If activating the button on the controller grounds the controller IC input pins you could remove the buttons and connect GPIO to the controller input pins. Relays avoid the need to remove the buttons.

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  • This assumes that they are at the same voltage. If they are not this risks damaging the GPIO pin the Pi or the remote. – Steve Robillard Mar 11 '18 at 6:04

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