The camera is hooked up now and I have a small enclosure for the infrared light source. Still need to hook up the photo transistor to detect the infrared light and work out the code for the keypad to enter the delay.
This is the adapter from the Canon N3 connector to 3.5mm stereo so I can easily extend and access the camera.
From the end of the cable going into the Arduino.
Two optoisolators are used to interact with the camera while keeping them on separate circuits. They are 4N35 optoisolators bought from a local electronics shop.
This is the whole circuit as of tonight. Hopefully the next iteration of it will be soldered to a board and on its way into an enclosure.
The infrared light source in its new enclosure with a switch. Running on a single AA battery and no other components.
It works! Couldn't tell without taking a shot with a modified camera to see the infrared light. When I get some time this week I'll probably be asking some questions about the keypad code. Thanks everybody for answering my questions in other threads thus far. Cheers!