Low Voltage Motion Sensor Switch

The refrigerator works off a contact switch and the light is not low voltage.

the voltage of the light is not important

just connect a switch on the door that works like a fridge door switch.

or you could use magnetic switches

a proximity switch is needed if there is a door that is opened and closes as the door could be used to switch the light

What about fast moving food stuff?

What you really need is a limit switch. you can connect to normally open or closed

Security shops also have magnetic switches for doors (signal or open when the door is opened) that you can fit.

you could look at a proxy sensor installed next to the metallic hinge.Depending on the sensor these will switch either + or - when the door opens metalic hinge moves out of sensor range and light comes on door closes and light goes off. One thing we do need is the wattage of the light you are trying to switch as most sensors usually control relays and the relay switches the load

You want a micro switch:-

Go to Digikey or mouser and search for micro switch.

What about using reed switches like those used in household alarm systems (low voltage 12V systems).

Most are normally open, & close when in proximity of a magnet, however you can also get changeover contacts, as I assume you would want contacts that close when you opened the door i.e. turn on the light.

They come in a variety of shapes & sizes for a range of applications.

http://www.google.com.au/images?hl=en&q=reed%20switch&um=1&ie=UTF-8&source=og&sa=N&tab=wi

In Australia you find them in Tandy, Jaycar & Dick Smiths Electronics Stores, (Radio Shack in US?)

Most 12 volt hockey puck style lights run off a step down transformer. In North America 120/12v. What I did was simply wire in a motion sensor mounted on it's side under a lower shelf so that when the door opens you can not see it. Although this is a 120 volt device it may do what you want. This is a standard off the shelf device and low in price. It works great and the led lights run cool so that heat is not an issue for what is stocked on the shelves. It also comes with a manual switch.

Elroy

I think what you did was a great but if I understood it you use the motion switch to break power on the 120 volt side of the transformer.

In my case this would not work since the my transformer will run mulitple lights in multiple cabinets. Doing it this way would be turning lights on in other cabinets that are not opened.

But maybe this would be the only way I would be able to do it if I can not find a low voltage sensor.

Thanks for the comments

Check RV and Marine suppliers for a low voltage equivalent.

Use a contact type of switch (limit switch, microswitch, etc). Much easier and more cost effective. Also, it's a much simpler solution.