Train reverse switch

albertsm · Joined: 09 Apr 2004 Posts: 6198 Location: Holland

This is a simple project i like to share.
I have a cheap Xmas train that only drives forward. But you need a lot of space for the rails. Recently i noticed that there are also expensive trains that driver forward and then go back. This way you only need a straight piece of rails.

So i decided as a fun weekend project that i would hack my train.
I used a special motor control IC : BA6287. I used this chip in customer projects so i had them. But you can use a relay or some FETs too, to control direction.

The processor is a small 8 pin tiny22 or 90S2343. It runs at 1 Mhz internal osc.
The train has a 3V battery and both chips work perfect with this voltage.

The code is simple : a reed contact on the bottom front of the train is connected to a processor pin. And 2 magnets are placed on the rails. One on each end of the rail.
When the trains drives the contact will close when it drives over the magnet. Then the code will switch to reverse.

There is a delay because otherwise the train will halt again at the magnet. And effectively it will halt.