Add infrared detectors
Clive Heathcote and Ann Anderson explain how infrared detectors work, and how you can use them to add realism to the signalling on your layout.
Clive Heathcote and Ann Anderson explain how infrared detectors work.
Is there anything more impressive on a layout than watching a train pass a signal and for that signal to turn red? What’s even more impressive is then watching that red signal turn back to green. You probably think that to do this involves computer control and lots of complicated electronic wizardry. But that’s not true. In fact, it can be achieved quite simply using Heathcote Electronics’ infrared control boards.
WHAT IS INFRARED?
You may have seen how white light, when shone through a prism, splits into the seven colours of the rainbow (red, orange, yellow, green, blue, indigo and violet). Beneath the red is a colour humans cannot see. This is infrared, which can be seen by snakes, frogs… and mobile phones. Heathcote’s control board emits and senses infrared. Mounted between the sleepers, it sends an upward beam of infrared. When a train passes over the beam, the rolling stock reflects it back to the control board’s sensor. Modellers have traditionally used things like reed switches, magnets, light-dependent resistors and current sensors for this type of train control, but infrared has key advantages: It works in the light or dark. Any item of rolling stock is detected. You don’t need to modify your trains in any way. It works with both analogue and DCC control systems. Infrared detection can be put to many different uses on a model railway, from locating trains in hidden sidings to automatically operating points. Heathcote Electronics’ first infrared detection board was named the IRDOT-1 (Infra Red Detection of Trains). The IRDOT-1 was designed for train location for hidden sidings or for automatically controlling trains (such as on back-and-forth ‘shuttle’ sequences. Since then, Heathcote Electronics has released a number of infrared detecting boards for various uses. To make your signals work automatically, you’ll need the MAS Sequencer and the IRDASC series of boards. And the most complicated thing about them is their names!
The signal halfway along Shap bank on Graham Nicholas’ ‘Shap Wells’ is controlled using Heathcote Electronics’ infrared control panels. See the Summer 2018 issue (MR251) for more on this layout.
Above: Julian Birley has made good use of Heathcote Electronics’ infrared control panels on his Dinorwic quarry layout (featured in the next issue). This shows how inconspicuous the infrared sensors can be.