I've always wanted a simple light that I could wear around my neck while working or walking at night. Flashlights can be too heavy or unwieldy and I could never get ahold of those head mounted lights to work very long. So with found parts and a few minutes of time, you can build this light.
By the way, I'm entering this into the LED contest so please vote for me!!
Step 1: Step 1: Materials
Here is the parts laid out. Not shown is the chain that I used to wear. In later versions, I used a zip tie to hold the chain and black spray paint to mask the pill bottle cap. Also note that the switch shown is not the one I ended up using. I used a SPST push button switch.
Step 2: Step 2: Attaching the Switch.
I used the soldering gun to melt a hole in the cap and threaded the switch into place while the plastic was still warm. I then trimmed and tinned the wires.
Step 3: Step 3: Attaching the Battery.
I soldered the positive side of the battery onto one of the wires. Lousy job I know...
Step 4: Step 4: Attaching the LED
I soldered the LED into position being careful to get the polarity correct. I can't stress this enough. If in doubt test on a spare battery then clip one of the leads shorter than the other and remember which is which.
Step 5: Step 5: Finishing Up.
Make sure everything fits into the bottle with the light as close to center and pointing down as possible. I wrapped the battery in electrical tape so that the possiblity of shorting out was reduced.
Step 6: Step 6: It Works!!
Now you can attach the chain, string or whatever to the bottle using either a rubber band or zip tie. I recommend using the zip tie, it'll look better. When I test it in my apartment, I can still see it at a distance of about 10 feet.