Just to prove that I haven’t been only playing video games, I humbly present to you a simple opto-isolator test circuit. This is the first step to remotely triggering my camera’s shutter remotely without putting it in any danger of a voltage spike from the rest of my motion control system and Arduino. The optocoupler is essentially a light-driven transistor with no physical link between the input and the output. The next step for me is to wire this up to the remote trigger port of my Nikon and code up a crude Arduino sketch to try it out. For that I’m using the 2.5mm TRS to accessory jack cable that came with my knockoff Nikon battery grip, a 2.5mm to 3.5mm TRS cable, and a 3.5mm TRS jack to make connect my trigger circuit to the camera. I could probably hack my actual remote trigger, but since I don’t have a spare I figured I’d do it the less-elegant, but nondestructive way.