Last year one of the guys on the BLF discussion board bought some stuff called Quantum Tunnelling Composite that he wanted to play around with. He had to buy a bunch of it and I had never even heard of it before and he didn’t have much luck with it. It is some kind of rubber that conducts electricity when compressed, but it doesn’t conduct when it isn’t compressed. In between it can give you varying results. So his idea (which he had seen somewhere else) was to put it in a flashlight and then adjust pressure on the battery and QTC to get variable output by tightening or loosening the head of the flashlight. Because he had a lot of the stuff he ended up giving some of it away to others who wanted to play around with it too and they came up with ways of using it. It works best with a simple on/off flashlight. You turn it to On and then adjust the pressure. Those people had some success and made videos of it in action. Anyway, now the guy is ordering some more and offered to mail it to people at cost, so I asked for a few pieces. I like it just for the cool name, which is explained on Wikipedia as having to do with electrons tunneling through the rubber stuff to get to the metal pieces that are in there. As it is compressed, the metal pieces get closer together and apparently there are some quantum effects going on.
Whatever. If I can make it work in a flashlight that will be cool. I have a kind of half-broken flashlight that uses AA batteries in a really tight fit and it might be perfect for that.
Here’s a post where a guy videotapes a highly modified Mini Maglite that he has fitted with QTC.