Joule Thief LED Flashlight

thingiverse

I'm a huge fan of Joule Thief designs, but without an on/off switch and enclosure, they can be quite clumsy to use. That's why I created this flashlight with protection, an on/off switch, and easy battery swapping in mind. Simply unscrew the enclosure to power off or fully unscrew it to remove and replace the battery. If you're not familiar with Joule Thief technology, take a look at the Wikipedia article: https://en.wikipedia.org/wiki/Joule_thief . In short, it's a simple DC-to-DC converter that allows you to harness energy from "dead" batteries. You can even repurpose parts from a dead CFL bulb to make one. Just remember to be careful when handling fluorescent light bulbs - they contain mercury vapor, which is highly toxic and can't be removed once it enters the body. It's especially hazardous for growing or developing humans. Alternatively, you can build similar converters using inexpensive discrete components available at your local electronics supplier without any risk of mercury exposure. The new v3 front end design is more compact and streamlined than its predecessor, making it a preferable option. Post-printing, connect a length of wire to the negative base of the battery and form a ring around the threads. Be sure to circumnavigate the battery in a counter-clockwise direction so that as you screw on the electronics enclosure, the wire isn't drawn towards the positive end but instead slightly outward. Next, insert the electronics and LED into the enclosure, making sure the positive and negative terminals protrude towards the battery. The positive terminal should be coiled around the center of the battery cap, while the negative terminal should be fashioned into a small hook that fits snugly into the divot left in the threads of the electronics enclosure. Some finesse may be required to get these contacts just right. While this design isn't as smooth and satisfying as the now-discontinued machined aluminum flashlight that inspired it (CMG Infinity), it still gets the job done.