A digital Canon SLR? If I recall, there is a group of pads inside the the battery door. Bridging these pads results in focus adjust and shutter release. I used a 1K resistor (or something) to play around with this. I was going to make an RF remote control for my camera but got side-tracked with something else (about 5 years ago). There's a bunch of info on the net about this stuff. I think you can use just a relay to do this...

I'm missing the point of using the kitchen timer. You can do everything you want with just the PIC...