There are many builds on the web of DIY shutter release cables for Canon digital cameras. This Instructable is only about my build of the switch and cable. Installing the software and getting it to work is up to you.
I'll be using an open source program called CHDK (Canon Hack Development Kit). The program boots a mediocre point & shoot camera and gives it extra features you only find on the big dogs.
Read about it here: http://chdk.wikia.com/wiki/CHDK
I'm just a newbie using CHDK. If you have any technical questions, please go to the forums.
Step 1: The Cable
You will see this circuit on many posts. It works as both a one-push and two-push button.This remote is going to be really cheap (like me), so I'm using the cable that came with the camera. Length is around 3 feet.
Any mini-usb cable that fits your camera will work.
We will be using only the red and black wires.
Step 2: Git Yer Batteries
Find a 5-Flags® lighter with built-in flashlight at the local store. I bought this one at qwikie mart for $1.19.
Take out the screw on the bottom and...HEY, LOOK! There's three batteries in a holder, and a pushbutton switch! This is perfect for the project.
The lighter still works just fine without the flashlight.
Step 3: The Battery Pack
Remove the LED and save it for another project.
I used a piece of 22g bus wire to replace the positive switch contact. After bending the wire into a suitable position, solder the ends to secure it.
The negative wire simply slides into the holder and is held in place by pressure against the battery.
Step 4: Finishing Up
A little bit of strategic heat-shrinkery and we are good to go.
As built, the switch is more solid than it looks. Should work for a long time. But...I'll still be looking for a small enclosure to upgrade.