I built a joule thief flashlight as part of a workshop at a security conference in 2018. We bought a kit that had all the parts, and then soldered them together. For a beginner soldering project, this is excellent.
Unfortunately, I don't think the kit I built is still available.
Here's some information I could dig up:
- https://www.gigaparts.com/etow-humanalight.html
- https://aa7ee.wordpress.com/2014/08/18/the-humanalight-a-fla...