(Archive of: http://www.thing-a-day2.com/2008/02/12/day12-thing12-helmet-taillights/)
One of our local dorkbots put an arduino in a bucket the other day and I got inspired to put one in my head bucket.
I lined the two largest holes in the back of the helmet with foil tape (for ducts) and then built two boards with leds and mounted in the area with my head. I glued a 4 pack of rechargable AA batteries on the top and plan to mount the 5000 mcd led in the front in the next day or so. While I am testing it the arduino run time board is taped to the outside but I plan to mount a really bare bones arduino under the battery when It is done.