Light and minimalistic USB Flashlight / Bikelight

 Last afternoon, I had some time and wanted to craft something. I decided, that I need a light flashlight. Since I have to carry a powerbank to my bikepacking trips, I made an USB flashlight:

It is made just from a 1 Watt PowerLED, a LM317 Voltage regulator, some resistors and  an old usb cable. These parts are available in nearly every electronics store. If you want to build your own, you can use this link to find out, how much resistance your circuit needs. Just enter the current your LED needs in mA, and you will get the resistance in Ohm. With an USB Port, you can at least run a 2.5 Watt LED. A powerbank should be able to provide a lot more though.

With this small powerbank, my lights shines over 5 hours. I've chosen a not so powerful LED, because I don't want to waste too much energy. 1 Watt is still powerful enough for walking or slowly riding a trail. It could help in incident, like tent damage, nights too cold for your sleeping bag, or if you have to move in the dark due to an emergency.

The circuit before

All electronics covered with expoxid resin

The next step is to make a mount for my bikehelmet, so I can use this solution to save the weight of a 

a headlamp. I could also make an usb port facing in the fron direction of my bike, in order to have a bikelight, but on my trips I almost never ride in the dark.