This divelight is made from an aluminium tube (25cm with 100mm diameter). At both ends aluminiumrings are welded. They have threaded holes. Screws hold the end parts. The ends are 14mm plastic or persplex with a groove of 4mm depth for the o-ring sealing.
Inside are 41 LEDs (11000 mcd), switched by 2 Reed-contacts. Also a gel lead acid accumulator with 1,9 Ah. The light is quite simple to build and has no electronics. But I intend to add a depth discharge surveilance and maybe a display for the remaining power time.
The building time was 14h for the casing and 3h for the electronic parts. The light has been tested down to 10m. The light is comparable with a more expensive divelight. Copy on your own risk. For questions To.Burkard@t-online.de
Hint: Friends have a company for machinery construction. There are lots of parts as surplus, e.g. the tube. So just ask at an appropriate company. You also need a lathe and someone to use it. If you let it build the cost might be quite high. We used a CNC lathe which costs 40 Euro per hour.