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!