Japanese firemen and policemen dance for light

Don’t you just hate it when flashlights run out of battery? The natural thing to do would be turning it off and shaking it, hoping that the chemical paste in there will somehow mix and squeeze a few drops of juice left. Japanese company Daisaku-shoji is selling this battery-free flashlight that can shine for a good 20 minutes with half a minute of shaking. The basic principal is just the highschool physics of magnetic induction. The best part is that this thing is 300m waterproof and floats on water. Drop tests showed that it wouldn’t fall apart even when dumped from 1.2m to hit concrete. These flashlights are selling in Japan for $80, in fact, a lot of the Japanese disciplinery forces have started carrying these around. — Sam Chan

NightStar Magnetic Force Flashlight  [Daisaku-shoji]