Connecting a GoPro remote to an Arduino

Why
To make the camera rig do what we wanted it to we needed a way for the Arduino to trigger the camera. A normal DSLR would have a connector for external shutter, but on our rig we would be using a GoPro camera.
So how do you connect a GoPro to an Arduino?

Well, cutting the case and soldering to the GoPro internals was an option, but not a good one. Modifying the remote control however was a less scary endevour.

How?
We opened the remote up, cut a small hole in the case and soldered two wires to the pins of the record button.

We then made a simple transistor circuit that shorts V1 to GND, exactly the same as the button does on the control. This image shows the circuit before it got wrapped in heat shrink.

The remote also still works as a normal remote. We could also fill the remote with glue to make it waterproof again, but that will be a future mod.

This is the circuit layout. Notice the arduino and the remote shares GND. We can do this since the remote control uses a battery, otherwise we would have used a optocoupler in place of the transistor to safeguard against voltage differences.