Cheap Airwire Dead Rail DCC

With a few inexpensive parts, it’s possible to put together a very reasonable Airwire Battery DCC system using off the shelf components. It uses a motor controller rated at 13 Amps so it will drive any DCC decoder on the market. No programming required.


First you need one of these-
GWire Receiver


And one of these for $10
Motor Driver


One of these for $8
5v Converter


The first thing you have to do is solder some leads to the Gwire device so you can power the receiver with 5v and get to the logic level DCC signal. It’s quite easy to do, instructions are here: Gwire Modifications (Note that this page references another DCC amp, my original design. The commercial version mentioned on this page is more powerful and also cheaper)

You will also need to change the cable slightly on from the receiver to the amplifier. Remove the red wire from the cable and just use the yellow, white and black wires.

Now to put all the parts together- The only slightly tricky thing here is that you have to adjust the set screw on the buck converter to dial in the correct voltage. You will need to attach the battery power to the inputs on the converter, then, using a voltmeter, turn the screw until you see 5v on the output. (This is just for this specific converter, it’s possible to get 5v converters that are preset if you look around on Amazon or Ebay)

The remaining hookup is pretty standard. Take the output of the buck converter (5v) and power the gwire receiver with it. Take the same 5v and ground used to power the receiver and connect that to the motor controller. The white wire on the motor controller (pwm) is connected to 5v, the black wire is connected to ground and the yellow wire (dir) is connected to the RX- on the Gwire receiver (which is the logic level DCC signal). Basically, the gwire receiver gets the signal from the T5000 and feeds it to the motor controller. By wiring the controller like this, the output now follows the logic level signal but at whatever battery voltage you pump into it. Very simple DCC.

I modify my amplifier connector cables to have a standard servo connector on the end, however that is not required in this situation, you can directly solder them if you wish.

You will also want to add a fuse, a switch and a jack to charge your battery, this is not shown on the above diagram. Here is a schematic of that:

Here is a video of it in operation: