Make yourself some properly bright bike lights
This wiki is new, so please bear with me, whilst I fill it out a bit...
Why?
If you want some seriously bright cycle lights (for offroad maybe), or if you want to do over-night events, then maybe the cheaper LED lights that are on the market at the moment aren't up to the job. You can get similar commercial designs, but as these are relatively low volume products, with correspondingly high markup, you might not want to pay the £200 plus that they seem to retail for at the moment.
These LED based lights are:
- More efficient than most halogens (more battery life / less battery weight)
- Cheaper, and less difficult to drive than HID bulbs
- LED emitters are more robust than conventional bulbs
- Dimmable without the efficiency going down the toilet
They also have Good Hack Value (mine certainly turn a few heads).
3 LED version: 
2 LED version: 
Getting a good impression of how well they illuminate at night is difficult, but you can at least see what the lights themselves look like at full power on a sunny afternoon (very bright clear day at ~3pm in June, I think): 
How?
If you are reasonably handy, you can put some of these together, you can of-course use your own design, but this is the basic spec. of my setup:
- 3x Lumileds Luxeon III - Lambertian, White, and associated optics
- 12x 2500mAh NiMH rechargable batteries
LEDdynamics LuxDrive 1000mA constant-current drive (externally dimmable version)
- An old aluminium heatsink from a PC (Pentium Era)
- Around 10 Watts output at full power
- Dimmable (with no loss of efficiency - unlike halogens, you actually get a slight gain in efficiency at lower powers)
- Full-power battery life of ~2.5 hours (5 hours at half power etc...)
If this looks interesting, have a look at the construction details for my (Tim) lights at EveryonesLights.
What?
I set up this wiki in the hope of pulling together information on Lumileds Luxeon based bike (cycle) lights, as well as those using similar high-power LEDs. There are quite a few sites on the web with DIY project photos, but you seem to have to look hard at the moment to find them all.
Lumileds Luxeon LEDs are high-power Light Emitting Diodes, with a better efficiency than most halogen lights. Together with the other benefits of LEDs, this led me to make myself some 10 Watt LED cycle lights for around £60 (vs. £200 plus for the commercial versions).
Why Originally?
I (TimSmall) decided to build some high-powered bike lights. My original motivation was when I lost the bulb holder for my CatEye HL-MC200 halogen cycle light, after it had a bash. This was the second HL-MC200 of mine which this had happened to! I'd paid about £25 for each, so I decided to change light at this point.
Since I'd bought the HL-MC200, LED lights seemed to be progressing (e.g. you could actually get LED lights which were as bright as the HL-MC200).
I was also planning to take part in the 2005 Dunwich Dynamo, and the battery life (and indeed brightness) of the HL-MC200 with my chosen NiMH rechargeable AAs (between 1300, and 1900 mAh), was nowhere near long enough (about 2-3 hours continuous, from memory - I think I used two or three sets last time I attempted it).
So I started researching, I considered the HL-EL500, and found them on Ebay at a reasonable price (£25, or so each I think). I did some more research, and found that they used a 1 Watt LED - Impressive, but apparently the built-in current-regulation circuitry didn't work particularly well with NiMH rechargables - you got half a Watt for most of the run time.
Acording to a few sources on Usenet, the LEDs that the EL500 use are Lumileds Luxeons (original 1 watt versions). A bit of web searching showed up a couple of people who had made their own Luxeon based cycle lights, and that you could buy the 3 Watt Luxeon III LEDs for about £10 each.
"Hmm, I can probably do that...", I thought... I didn't do the Dynamo in the end, but I did eventually get around to putting the lights together when the evenings started to draw in during September. I'm now using them daily on my commute.
Parts Suppliers
http://www.ultraleds.co.uk/default.php?cPath=35 UltraLEDs (UK)
http://www.luxeonstar.com/item.php?id=1811&link_str=330&partno=LXK2-PW14-U00 New Luxeon K2s - 5w ish, but not sure about driver, or optics suppliers at the moment (see link).
http://www.luxeonstar.com/category.php?id=196&link_str=196 Luxeon IIIs
http://www.ledsupply.com/ LED Supply (US)
http://vapextech.co.uk/ UK Vapex Importers - these are Chinese batteries, but the quality seems good so far, and the pricing is very good. AAs, and model car packs are definitely worth considering. Nice range of chargers too.
http://www.dealextreme.com should see you LED's, regulator, batteries, charger, plus lots of gadgets!
http://www.taskled.com/bflex.html current controller
Commercial pre-built lights are on the EveryonesLights page...
Wiki Stuff
This is a wiki - you can contribute. Please do! Especially if you've built some lights (either from your own design, or following my basic instructions).
Interesting starting points:
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