I just started geocaching recently and have been using my garmin car gps. It works pretty good other than that a long day (or night) can kill the battery. I was inspired by this instructable:
DIY More Efficient Long-lasting USB or ANY Charger
Now I really did not intend to do anything different than what was in that instructable. I was walking around the dollar store looking for a cheap project enclosure and I came upon the flashlight section. Eureka! The perfect enclosure with battery holder and switch included.
I did not like the lights available at the dollar store but managed to pick up an aluminum 3 aaa Noma LED light at another store that fit the bill almost perfectly.
Please check out my other instructables and I also have a diy podcast called mechanicalmashup.tv
Step 1: Taking Apart the Light
The first step is to remove some of the guts of the light. I needed a vice to loosen the threads for the LED housing, but other than that it was pretty straight forward. The LED was desoldered to be used in a later project. I drilled a hole in the lens to allow a USB mini cable to squeeze through. Seems like everything is good to go at this point. I just have to wait for the Anyvolt regulator to arrive in the mail...
Step 2: Oops!
So on arrival of the regulator I knew I was going to have a slight problem. The chip was a little to big to fit into the old bulb/reflector housing. What to do? I was on a bit of a time crunch and did not want to go buy another flashlight to rip apart.
Another thought I had was to make it more versatile by putting a female usb plug into it instead of the male mini. This would allow it to be used with other devices like an ipod.
I soldered the chip into the old LED wires (bypassing the resistor) I popped the lens off the end of the flashlight and fit everything together the best I could. The chip stuck out a good 1/8". I know I lose cool points for finishing it in such a ghetto way but I used hot melt glue to seal the end.
Step 3: Testing
Even though I used a volt meter to check everything out, I plugged my sons crappy old mp3 player into it first, instead of my gps. (I would have bought him an upgrade if it had fried)
I guess that even though this project did not go perfectly, the main point of it is that you could get a project enclosure with battery holders and a switch for a dollar by using a cheap flashlight.