Using a relay to bypass a button

Question

I'm using a relay to bypass a button thats connected to a Raspberry Pi. Code works fine, relay switches fine, and if I connect the 2 wires that bypass the remote it works fine too.

I cannot figure out why the button bypass isn't working when I put it all together. When I switch the relay via code, the relay switches to complete the circuit, but the button doesn't get bypassed.

Any advice?

My ultimate goal is to use a Raspberry Pi to trigger a Go Pro via the remote that's wired to bypass.

Heres an example of what I'm basically doing, Gopro remote hack raspberry pi, I have the button hard wired. If I touch the two ends of the wire, It acts as a button press. I try to do the same using the relay and I wont work.

I have tested the relay, the wire, and the code and they all work individually it would seem.

Heres a image. currently GoproRemote+ is plugged into 18, GoproRemote- is plugged into GND

Answer 1

You can use a simple transistor to achieve this. It is much simpler than using a mechanical relay, and much smaller.

For NPN Only

• You just need to find the + voltage (signal) of the remote wire and wire it properly to the transistor (C) Collector
• Then the GND is common for the Pi and the Remote and wired to (E) Emiter
• GPIO triggers the (B) Base
• R1 are values between 1K and 20K safe.
-

Trigger the GPIO high and the switch is "pressed"

^{simulate this circuit – Schematic created using CircuitLab}

^{If you dont want to specially buy 3904 you can try and salvage a transistor from some spare thing lying around. Anything from power supplies to remotes. Find the transistor number and check if its PNP or NPN, and what voltages it handles. Usually almost any transistor will work in such circuits as long as its NPN. PNP may not work and required different wiring and setup. More info}