Scuba Laserpointer

The assembly UW-Laserpointer.SLDASM contains a Laserpointer for underwater use. It is based on a green 5 mW Laser I bought for 4 Eur from a street vendor in Shanghai. It is super cool to use for night or cavern diving, or watch the total reflection of the beam when pointed in a flat angle from below towards the water surface. At the reef some fishes are attracted and hunt the bright spot, others flee. You can also shoot a "tunnel" into fish a swarm, because the fishes keep the same constant distance towards the beam. Very funny! The body is made from sea-water resistant aluminium, the frontwindow is a microscop cover slip glued into place and the trigger is a small reed contact driven by a magnet from the outside.