420kg of weight and a drop height of say 1.5m has an energy of 420x9.8x1.5 = 6174 joules.when your setup draws 3.5 watts or 3.5 joules/s it will run 1764 seconds or less than half an hour,in practice less because there is also loss in the gear and generator. and then you have to pullup the weight again...
yepp, true this actual device is scaled for LED lights. 420 kg weight is not that terrible much if you have gears to convert ratio.
New layout! Now everything fits very nicely inside the box, CHIP is inside of awesome Zebra case, and still there is plenty of room!
All thanks to cheapo L-shaped USB connector (less than $1 a piece).