I'm ready to get my Master Electrician badge now! After lots of careful study, calculations, research into the basic theory behind LEDs, I was able to solve my latest problem - the all-dead LED problem. Just to test all of you, when you turn on an electrical device and it don't work, what is the primary probable cause? Think carefully - this is a trick question.
Do you give up? Well, today needed to work on something else in the garage, so I had to move the LED fixture out of the way first. So I picked up the "power Bricks", the DC supplies, and started to look for a good place to keep them, when I saw a short electrical cord laying on the floor. My Master Electrician skills then came into play. I went over my mental check list of short electrical cords, and checked off all of the possibilities - of which there was one. That is the cord that connects the 48 volt DC supply to the extension cord. Yep, it fell out.
So, it was time to test my analytical skills. I plugged it back in, plugged it into the extension cord, said "let there be light" and was immediately blinded again!
To avoid another of these complex electrical problems that seem to dog me, I ran and got the PAR meter - ok, I don't do much running now, but I got it in any case - and took some measurements. Another triumph for the Master Electrician. At about 20 inches from the light I got 50-70 micromols, just as I was shooting for!
The light is pretty uniform, hitting 70 only at what appears to be directly above a LED, but it could just be my unsteady hand trying to hold a constant distance as I moved the sensor around. In any case my design does give about what I wanted, at the height I wanted it, in air. With water in the picture I suspect the intensity will be a little more, due to the focusing effect of the air to water interface. I feel good again!
