The Concept

The interlocking needed to be operated from two operator positions one in an aisle and one in a “crawl in and pop up space” in the central island.

After some design work we settled on a panel layout which had to include the ability to set three turnouts along with the interlocking features.

The single track crossing the double track main is the “RED LINE” on the panels and also know as the “E route” as opposed to the double track “BLACK LINES” also known as the “NOT E route”.

I decided to use one of the spare TI Launchpads I had and a 5V 1Amp wall wart to power the controller and the indications on the panels. I used bi-colour LED’s to indicate the Route selected. Apart from interlocking the tracks I needed to make sure that only “one” Panel could have control at a time.

There are 19 Control and Indication connections and seven connections for turnout operation. Panel A needs feeders 8.2 metres long and Panel B 4.5 metres long and the controller is near the power outlet!

The control status LED’s are driven by Optocouplers (at the top) which switch their supply voltage based on the micro-controller “pin state”. The relays switch the two sets of 7 LED’s that show the current route and one the DCC track feed.

Here is a link to the code.

Here is a link to a Video that shows some details