The Perfect Light
Garry writes –

The perfect LED light is designed for cavers who want an efficient, uniform and constant bright light for caving. This article contains some very specific technical information and it is assumed the reader has a basic understanding of electronics. To build the light, the reader also must have some experience soldering, drilling, wiring and cutting small objects. The list of required tools include a multi-meter, Dremel drill and soldering station. The electronics are available from major semiconductor manufactures has “evaluation” kits, but nothing should prevent the reader from “rolling their own” design. The principle cost of the light is the white LED’s. The best white LED’s are made by Nichia Corporation and are expensive. However, it makes no sense to undertake the project without starting with the best LED’s available.

The Perfect Light –Link.