If you have a Canon camera that supports the CHDK firmware, there’s no need to buy an expensive shutter release cable. You can make one for a few bucks with a handful of parts and a sacrificial USB cable.
Over at photo blog Kiss The Asphalt, they share a simple guide to creating your own shutter release cable that works on any Canon camera that supports the aftermarket CHDK firmware. The crux of the simple hack is the fact that you can turn on a feature in the CHDK firmware that turns any button press into a shutter release and it will interpret a pulse down the USB cable as a “button press”. Rig up a button to release a small burst of 5v current down the USB cable and you’ve got yourself a cheap remote trigger.
Hit up the link below for the full guide including pictures and a wiring diagram. Also, if you know of any clever hacks like this for other cameras, share a link or two in the comments.