Power

Power provision is a fairly important, unless you’re building a clockwork or steam layout that means electricity!

My requirements were for 5v power for the computer and some control systems, 12v for the locos, lights and more control systems and then a separate supply for the decoupler electromagnets. At the time of building I wasn’t certain what voltage I’d need for the latter and I didn’t want the engines to slow down or the lights to flicker when they were used so that determined a separate supply.

Being in the IT business I have access to a collection of various power supplies. The one chosen came from an old external DVD drive and provides 3A each of 5v and 12v which should be plenty for the main supplies.

Wire Colours

For the 5v and 12v feeds (other than those using jumper cables) I’ve obviously stuck with the standard red and black wire colours for +ve and -ve. The feeds from the motor controller use the same cable but positive and negative don’t necessarily have any meaning so I’ll just refer to these as Red and Black connections.

Distribution

To distribute both power and the control connections to all the various boards I built a simple connection board on a piece of stripboard; it was quick to do and it makes life a lot easier. That board is located close to the centre of the baseboard for obvious reasons. I also built two small distribution boards for the black connections from the motor controller to the tracks. Some people would disagree with the use of the screw terminals but it means I can easily remake any connections.

Main Distribution Board
The power connections are on the screw terminals at the edges, the hookup wires from the Pi go to pins in the middle

These two are simple crew terminal distribution for the Black track connections