I originally bought a camera timer off Amazon that was pretty cheap, about 15$. I decided it had a lot of features I didn't want such as photo count, delay start, ect...
So why not make a much simpler device that is smaller, more efficient, open source and made by myself!
With the amazing technology as employed here, this device can run for up to 200 hours (with an average current draw of 2 mAh).
Step 1: Components
1. ATTINY85 microcontroller
2. DIP Sockets Solder Tail - 8-Pin
3. Reed Switch 5V/1A
4. Polymer Lithium Ion Battery - 400mAh
5. 4 Position DIP switch
6. 2.5 mm Male Stereo Cable (can be found on ebay and spliced)
7. Universal Component PC Board
8. Soldering Equipment
9. Arduino for programming
I was able to find everything for less than $20 and some were even reused parts!
Step 2: Layout
It is a fairly simple layout as seen on my original design. 3 pins of the DIP switch will act as a binary counter (giving 8 different combinations) while the extra switch will be an I/O switch. The ATTINY85 and Arduino have pullup resistors on their digital output pins that can tell the state of a switch when connected to ground. That will help us out. Another digital output is connected to a 5 volt reed relay switch that uses a magnetic field created by the current from the microcontroller to close an internal switch that will activate the shutter on the camera.