LEDs Turning them On and Off


Posted on Feb 6, 2014

The last installment in this series ( LEDs 102 - Use On Board Trains ) ended with a few thoughts about turning battery powered LEDs on and off. In this article I would like to explore several options for turning LEDs, and other things on your railroad, on and off. A simple on/off toggle switch meets the first and last requirement and, depending on


LEDs Turning them On and Off
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where you put it, the other two as well. I have mounted small toggle switches under cars and tenders to do a variety of things and find them to be a good solution so long as I can remember where they are located under the car! The switch pictured here is inside of a tool box on a tender. A reed switch is a magnetically activated switch that is frequently used in model railroad applications. They are also commonly used to trigger burglar alarms when a window or door is opened. Most are composed of a small glass tube that contains two small magnetized contacts that normally do not touch. This makes most reed switches Normally Open, sometimes referred to as NO as opposed to NC switches which are Normally Closed. When a magnet is brought near the switch the two contacts come together and the switch closes. When the magnet is removed the contacts spring apart and the circuit opens. If you would like more information on reed switches they were covered in some detail in my article Garden Railway Sensors - Part 1 As I mentioned in the last article you can use one of these common reed switches to turn LEDs on and off by gluing the reed switch to the inside of the roof of a car. Placing a small magnet on the top of the car will turn the LEDs on and they will go off when it is removed. As you can imagine this presents a few problems. You have to find a place where the magnet is not likely to fall off as the train moves around the...




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