Control Switch Saves Shelf Lighting

When my wife and I remodeled our kitchen in the mid '90s, we decided to build a new kitchen in a different area of the house. This gave us the luxury of redoing the kitchen without having to first shut down the old one. This in turn relieved much of the urgency, and we quickly developed a willingness to prototype things to see how they would work before committing resources. We bought cabinets, which we installed and found that there is a wide assortment of accessories that go with them. One such accessory was a pull down bookshelf which mounts to the underside of a wall cabinet.

We did not skimp on the under-cabinet lighting, but soon after we started using the kitchen we realized that, while there was plenty of light on the counter tops, there was only ambient light on the cookbooks. To fix this, we installed a small under-cabinet halogen fixture which fit nicely between the stowed shelf and the bottom of the cabinet. It shined much needed light on the books resting on the deployed shelf.

A little later, when the smoke alarm went off, we knew immediately that we had an issue. Halogen bulbs get very hot and when the shelf was stowed, the system quickly overheated. The halogen fixture was wired into the main under-cabinet light circuit and could be quickly turned off for the moment, but we needed a solution that would permit using the counter lighting while the shelf was stowed. To accomplish this, I found a salvaged micro switch in the basement and installed it in the hinge mechanism in such a way that when the shelf is stowed, the switch opens and the halogen light goes off. Problem solved!

This worked well for several years until my wife decided she needed a wider shelf to accommodate multiple references. We made this from matching scrap wood left over from the cabinet installation. Reusing the same hinges made the switch available, but it was not robust enough to power two halogen fixtures and one was not enough to illuminate the wider shelf. We were able to find a nice thin light bar with three powerful LEDs to replace the halogen fixture. This too fit nicely between the stowed shelf and the underside of the cabinet, and the cool LEDs did not need to be shut down when the shelf is stowed. However, the switch was already in place and wired so we retained it and now we do not have to tolerate light leaks from within the stowed system.

Tell us your experience in solving a knotty engineering problem. Send stories to Rob Spiegel for Sherlock Ohms.

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