Check out this cool little gadget for emergency uses. It’s water powered Flashlight titled as “NoPoPo Mini Lantern Flashlight.
The NoPoPo Mini Lantern is pure craziness: a lamp powered with nothing but water! Simple to use, rechargable almost anywhere, and lasting up to ten years without losing charge, the NoPoPo is a perfect addition to any emergency kit, camping gear, survival set, and more. The versatile mini lantern can be used as either a flashlight or a unidirectional lantern; just slide the cover up to change modes.
Folks at RGS said using urine as the substitution probably doable. But I’m not sure if the NoPoPo battery will be damage or not. But overall, this is a cool emergency gadget despite of its retro looking.
You can find this NoPoPo water-powered flashlight at JapanTrendShop for only $39 + $18 worldwide shipping fee.