I'm doing the Scott 24 Hour mountain bike race this weekend with some mates. To mountain bike at night, you need decent lighting. The proper lighting kit is massively expensive and could easily be more expensive than my bike, so I needed a plan B.
So I bought an LED headlamp and very bright LED torch. The headlamp, fortunately, fits under my helmet. The torch is plenty bright, but I needed to work out a way to mount it. We had a few spare bike light mounting things floating around, so I combined two of them and fortunately they're able to screw together. So one goes around the handlebars, one goes around the torch. Quite neat really.
I'll test this setup out tonight on the way home, with the bumpy and dark backstreets of Erskineville being the test ground. My main worry is whether it'll be steady enough, as there is some movement in the joint. If so, I'm thinking some little bits of rubber acting as braking washers.
The other problem is the torch takes CR123A batteries -- those short, squat things that you put in cameras. These batteries are bloody expensive -- $12 each at Dick Smith! They're Lithium chemistry, which means they hold a fair whack of power, but I really have little idea what my burn time will be like, so I'll probably have to buy another set of these batteries and hope that'll be enough. Longer term I think I'll look at attaching some kind of big rechargeable battery pack.