I am planning to construct a halogen headlamp for night rides and winter commuting. I usually like to build my own things, which gives me a lot of satisfaction and saves money at the same time. The design I am considering is from here:

http://www.ladyada.net/make/bikelite/index.html

Anyone else used this protocol or any other? Please enlighten me with any information/experiences that you may have. Thank you guys and gals.