I have been wanting to make something useful with the joule thief circuit design and some 1W star leds that I have. I found an old bicycle light that used a 0.5A 2.5V halogen bulb and two C size (LR14) batteries. It looked like it would be a good candidate to convert to led. I also wanted to create a light that would switch on automatically as the bike moves, and off again with a delay after the bike stops moving. In other words a motion sensor activated light that I would not need to switch on or off. That would Continue reading Motion activated joule thief led bike light →