Friday, October 24, 2014

Cyclone-proof housing for sensor

An ambient light sensor in service for five years that I have on the top floor of a building recently drowned. Well, that's because water accumulated in the aluminum can which housed it. And the reason water accumulated was that the half-inch aluminum angle that was propping the can up got bent back by storm winds. Below are photos I took back in 2009 of the flimsy aluminum can and anodized aluminum post..

Here's the poor circuit board all corroded.

I made sure the new sensor housing would be robust and would not suffer the same fate. I used scrap pieces of 1/16" x 1-1/4" square tubing, 3/32" x 1" angle, 3/32" x 1-1/2 angle, 3/32" x 2" angle and a short piece of 1" flat bar. for the post that would support the housing to the catwalk. All the parts were MIG welded together. The housing itself is the box of a very old and burnt transformer. And by scorched I mean the entire unit had been in a fire.

Here's the new sensor. Am still using the same Selcon brand plastic housing. The Selcon circuit is somewhere in my junk box.

Sensor and new housing installed. The housing is fastened to the post with only one stainless 3/8" bolt. This allows the housing to be oriented in any direction.

The square tubing is clamped to the catwalk railing with two stainless U-bolts. The cable to the sensor is fastened to the catwalk using nylon cable ties.