In the last post, we finished off by wiring up a bus wire for all of the common terminals of the solenoid point motors to connect to, and this is where we pick it up. The layout currently has old fashioned solenoid point motors – think classic Gaugemaster PM10’s and then think older! These motors only have three terminals; positive, negative and common return. If I were building the layout from scratch then I would have gone with Seep motors as they can switch the polarity of the frog, but we want to keep the layout cheap so we’ll work with what we have.
The DCC control system that I have decided to go with on Rhad Valley is DCC-Ex – an Arduino based system which will keep the whole thing rediculously low cost. You can build a command system to connect to your pc for around £20, or wireless via Wifi to your phone for around £30. When you think that a NCE Powercab is around £200 more than that, you can see why I’ve decided to go down this route. I’m also a programmer by trade, so the flexibility that the DCC-Ex gives you with regards to automation and sensors etc, it’s a no brainer to me.
Normally the method of point control with DCC-Ex is with servos rather than solenoids, but again we want to keep this build low cost so we have to work with what we already have. The problem we have here is that an Arduino can’t control solenoids by itself as the solenoids require an analogue switch with a CDU. So to this end, we’ll have to use a relay board to act in place of an SPDT switch; we’ll use one relay to power the motor one way, and another to power it the other. All of the middle terminals of the relay will be connected together and then onto the CDU, with the Normally Open (NO) terminal of the relay will control the direction of the motor.
With that all wired in place, we’ll leave it there for now as we haven’t set up the Arduino yet. Next on the agenda is powering the frogs with a juicer…
16 channel relay: https://amzn.to/4dT0n8Z