Re: night light

For my barn I bought a walmart solar light on closeout for 4$ and hacked it. This has t work in Northren ohio winters in the middle of the night, so away went the solar switch, and also the amber led in the 4 led package. Replaced by a nichia 12,000 mcd green and a few resistors and switches, and the cell was remoted to the roof on a piece of lamp cord. The idea is you leave the led on 24/7 drawing about 50 uA, so you can see the led to find the switch to boost the current without stubbing your toes, or tripping on tractor parts. The current draw is sized enough to pull the battery down somewhat each night, keeping the cheap nicads happy as they dont set doing idle chemistry. This scheme of a small constant current draw has kept the same cheap batteries working for 3 years, and the only glitch was after a hail storm, the roofers hired by the insurance company chopped the cord and tossed the cell off the roof, but that was a easy fix. The batteries are inside and dry, up above the door, and that is the trick. This barn gets cooking in the summer and frozen in the winter, so the scheme seems to work well.

If I had the cabin, I'd use a newer Cr:YAG based glow phosphor for the backup source, with cheap 68 cents a meter acrylic fiber optic, or just acrylic rods as the pump source, ie solar charging, no nicads, no problems except keeping the leafs off the fiber ends. BTW, polish the fiber or rods with one of those cd scratch remover wheels from Best Buy. The %$#@ thing did a lambda over five optical finish on the one fiber we tested. 6 foot of 1/4" acrylic rod from a plastics shop is about a dollar and twenty five cents. We have had no problems blending the Chinese phosphors in the 2 part cheap casting plastics from flower shops,.

Steve Roberts

element.

It takes some integration, but the hottest spots in our house are the beds, with a alpha counter you can find the outline of where people sleep. I guess we "leak" K40 and perhaps some carbon isotopes?

Steve Roberts

Thats interesting. I am going to test me also !!

The hottest spots in my house. Camera case holding my Pentax uranium ore coated lens. I also have an old Baby Ben alarm clock.

Its claimed that a good charcoal filter will not reduce the radon levels. Its also claimed that a good filter will filter the daughter breakdown products of the radon. I suppose the activity on the filters are the heavier breakdown products.

greg

Aren't those things amazing? I can't believe how bright they are.

But do they make better bandgaps? I dont have the gear to test that theory.

Steve