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Infrared LED

I mount two IR LEDs in each loco, one in each end. I use 1206 size surface mount LEDs, but other types of IR LEDs could work too. There is no standard way to mount these LEDs, it varies from model to model. Here are two examples, one Märklin 3374, where I have glued the LED with epoxy, and one Lima 288660 where I have made small circuit boards that I have screwed to the bogie with the already present screws of that model. It is important that the LED is mounted so that it will always be over the center of the track. Therefore, I mount the LEDs on the bogies and not on the body of the loco.

The LEDs have to be connected with the correct polarity. With these small LEDs, you can hardly see which side that is the anode and which one that is the cathode. Instead, I measure the polarity before I connect the wires to the transmitter electronics inside the loco.

Märklin 3374:

Lima 288660:

home : electronics : Train recognition system : IR LED

Last edited August 9, 2012