The batteryless torch
An item of technology that has only recently come into existence is the shake-to-charge no-battery torch. Unlike the solar and dynamo torches which are only useful as novelty items, these new devices are somewhat practical.
Dan's Data reviewed the first of these torches, the NightStar, and he liked it.
As a bedside table light, the NightStar II is great. When you're padding from your bedroom to your bathroom/kitchen/dungeon, you don't want a really bright flashlight messing up your night vision, and a good-sized light with a glow in the dark switch is easier to find on the bedside table. A little light you can hold in your mouth while you stealthily assemble a midnight snack would be nice, too, but you can't have everything.I wouldn't go so far to say that every home should have a NightStar II, but it is one of the neatest gadgets I've laid my hands on. Flashlight, nightlight, fiddle-toy, educational device, geek mantelpiece ornament. And it costs only $US39 plus shipping, which isn't stupidly expensive for what you get.
Well, that was a little expensive for just a plaything, so I was delighted to find a product operating on the same principles advertised at Dick Smith Electronics for only AUS$20. (Search for the Shake 'n' Charge Flashlight.) I duly purchased said product, and found that it was a Forever Flashlight, packaged for Australia by Swann. And the best news for Australians is that the Dick Smith price is lower than any US price (the lowest I could find was US$20).
So, is it useful? If you compare it with a normal torch, or any other light source, then you'll be disappointed with its low light output. However, if you compare it with darkness, then it will satisfy you. You won't be able to read a book for half an hour on one charge, but you will be able to read a map for a few minutes. And if you're walking around, you can shake while you walk to get an extra bright flash every shake, which is quite sufficient for most needs.
The Forever Flashlight is seemingly a lower-quality product than the NightStar. For example, it uses rubber stoppers at each end to stop the magnet, rather than the magnets the NightStar uses. But I think it's great value, as a plaything and something useful.