Attach one rare earth magnet to one button battery and tape one LED light to all of that. Now you have a THROWIE, a little light that you can toss onto buildings, cars, etc, that will remain lit for weeks. Each one costs about 30 cents if you buy the materials in bulk.
screencapped. Why magnets? Does it make it last longer or what?
>Idea from 2008 in 2016 /diy/
Which is a stupid idea for many reasons, one of which is lithium and heavy metal pollution.
If you're going to tell people about a project, make sure it's from the same decade.