Originally Posted by Gregcoyote
I may make a underwater housing with a thin piece of optical glass for the laser to shine thru. That way I could focus within inches.
that was my first thought when you guys first started discussing lasers.
Seems to be the best solution, no degradation from the glass/acrylic and the pin-point accuracy decreases the risk to other critters.
you could use a length of 1/2" rigid clear plastic tubing the required length and glue a lens on one end, secure the laser inside and then use a length of something like 1/4" rigid tubing to manipulate the switch.
you could even rig it up like a syringe to work the switch.