Arduino shuttle control - part two

More components have arrived so I've been able to finish construction of the shuttle control.

The breakdown of what this does is as follows:

Relay 1 is a bypass relay. When power is applied to it, the train control is routed via the Arduino and transistor within the board. When off, the train can be controlled manually.

Relay 2 is for track polarity - the Arduino can't directly control direction so this relay changes direction for me. When off the track polarity is normal and when powered the polarity is reversed.

Relay 3 is for the terminus station points, currently controlled elsewhere within the first board.

Relay 4 is for the sidings points, this is not controlled via the Arduino at all and is purely manually operated.

Transistor 5 is the speed control - the Arduino can pulse the transistor and vary the speed. This allows for smoother starting and eventually, stopping (when it's been programmed)

The Arduino Nano is component number 6. This is the brain. Programmable via PC, it's now mounted on socket pins so should it fail, or should it prove easier to remove it from the PCB for programming, it just unplugs.

The LEDs (number 7) are purely for indication. These show me the signal operation, points operation and speed regulation. The idea being that if a fault develops, the LEDs will help to identify where the fault is, ie if the Nano isn't generating the signal then the LEDs won't illuminate.

For added protection from accidental polarity reversal and short-circuits, I've added a number of diodes to the board. The Nano device is very sensitive and easy to kill so a few pence spent on diodes is money well spent.

Here the points are being tested, using the Nano and testing manual override. 

Time to test with a loco.

The Trix Western is used as a guinea pig:

It's ready to be installed.

At some point I will add current detection and then amend the program to slow the trains down as they near the station.

For now though this is a massive improvement on what's under the board currently - much neater, tidier and far easier for fault-finding!