https://www.youtube.com/watch?v=foqqxqW8aBg (https://www.youtube.com/watch?v=foqqxqW8aBg)
This is a really clever use of gravity to power a bright light. Not O.U. of course and not really much different from an old time gravity powered clock but, it works well and he has another video on how to replicate the device.
12 minutes of run-time is pretty good and, if one lived on the 2nd floor, the weight could drop a longer way giving you longer light periods.
Rimstar does some excellent work and his videos provide wonderful documentations and explanations. (unlike most of mine)
I posted this here to show a real life use of gravity to make good light and figured that the guys on this site can find many ways to improve Rimstar's device.
Again, not free energy or O.U. Just an excellent use of physics and his electronics skills.
Bill