I want to control a garage door opener with the PI, and the normal button is just a momentary switch.

Is it possible to use a PNP transistor to simulate a switch? Hook one wire to the collector, one to the emitter, and a gpio output to the base, then trigger it for 1 second or so? Or am I way off? I already have a magnetic reed switch to tell if the door is open or not. It would be cool if I could tell it to open or close remotely.

1 Answer 1


Simple answer NO.

It is theoretically possible if the devices share a ground, and polarities are correct (which assumes you have the circuitry of the device), however good (safe) practice would isolate the circuits.

Use a relay.

  • Yeah, guess that makes a lot more sense. At least I can use a really small and cheap relay since it's not much power.
    – AndyD273
    Jan 16, 2017 at 13:20

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