This instructable is about the construction of a dive light with parts that you can get at the local harware store.The ring at the back side is used as a rotary switch. This ring is coverd with ballbearing balls for grip. More details can be found at http://www.divelight.me.pn/ or http://www.duiklamp.me.pn/ for an explanation in Dutch.
Step 1: The parts
Basic parts are a 50mm alluminium tube of 250 mm and a number of PVC "plumbing" parts.
A Cree LED module is used as a light source. I've got mine from DealExtreme. The aluminum washers are used for carrying the heat from the module to the aluminium pipe.
Step 3: The internals
The 12 AA batteries are placed in four 3/4" PVC pipes. The ends are secured with a threaded rod that also holds the electronics. There are two reed switched that control the light output. They are actuated with a ring on the outside of the body that holds a magnet. See the first picture and www.divelight.me.pn.
Step 4: The electronics
The reed switches are at the top left and bottom left corner. The spring is used for charging of the batteries.
Step 5: The charger
Charging is controlled with this custom made charger. Charging 12 batteries in series shouldn't be done in a brute force. The batteries that I have used are of a low discharge type. So continuous charging isn't allowed either.