Thursday, August 06, 2009

"Magic Light" for a hall pantry/closet

We have a hall closet with a light switch on the hinge side of the jamb. Its easy to turn on before opening the door, but also easy to forget to turn it off. What we needed was the ultimate in convenience - a magic light.

A magic light is light which comes on when a door is opened, and goes off when closed. Perfect for pantries or closets which have no windows. Seems simple enough. The hard part is coming up with a momentary, push-button switch that is "normally closed".

I found such a switch in an old computer that was used as a chassis intrusion detector, which sets a flag in BIOS and lets you know if anyone has opened your computer case. For personal use, its probably the least useful feature that a computer's BIOS can offer.

The switch is rated for 125Vac @ 1 amp. Since this switch only turns on a 60W bulb, this is plenty high of a rating (we could do 125W if needed).

I wired some 18 AWG THWN wire to the switch with some crimp-on connectors.

I drilled a slight impression with a large forstner bit to give something for the switch bezel to recess into. Then I used a smaller bit to drill the hole for the switch housing. After I got drilled through the door jamb, I used a spade bit to drill through the stud towards the wall switch electrical box.

Fits well, and the door can close without crushing or putting pressure on the switch housing.

Then I brought the wires up into the existing electrical box using a piece of coat hanger as a hook, and attached them to the screw terminals of the existing switch. Now both can operate the light, however you would never need to use the wall switch again. I may just cover the electrical box with a blank wall plate in the future.

Here's a video of the switch in action:

The last thing I did was seal around the switch with a little white silicone to help hold it in place and stop the slight draft of air moving through it.

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