Fun with Relays

In the pursuit of being able to control as many things as possible digitally, while keeping effort to a minimum, I went down the rabbit hole of controlling some of the scenic accessories via DCC. Currently I have two buildings with functions that I want to turn off and on at will: a lighthouse, and a windmill.

The windmill came with a motor specifically operating on 16V AC. In anticipation of this, I built a 16V AC wire bus under my layout quite some time ago. That came in handy when the lighthouse was built, since it is capable of operating on that same voltage.

To control any accessories I intended to use the same MarDec devices which I am using to control servos: Arduino-based accessory decoders with high flexibility. Out of the box MarDec supports servo control as well as a number of ways to control other accessories, including steady power, flashing lights and similar. However, using the output of these devices to power accessories directly is only suitable for things that work with 5V and draw low amperage. For anything else, additional work is required. When you do a bit of research, you'll hear talk about Mosfet switches, transistors or relays. What you end up using is - largely - up to your confidence with electronics and appetite for complexity.

I quickly decided to go with relays. The other options don't readily offer themselves for use with AC, as far as I was able to determine with my limited electronics knowledge. Relays are quite simple to wire in, all they need is a power source and a signal, and then they pass through whatever is connected to the right contacts (within their specs, of course). How that's done with the windmill is shown in the below graphic.

The 16V AC are connected to the common and the Normally Open (NO) connector. A proper DC power supply is connected to DC+ and DC- connectors - in my case that's 5V, but these relays are available for different operating voltages. Lastly, one of the Mardec ports is connected to the IN connector, and the port is configured to provide a single steady signal when activated, which happens through a DCC accessory address. On activation, the relay is triggered and the 16V AC flows through to the motor in the windmill - or any other accessory wired this way.

What I learned about relays has also come in helpful for another small project I'm working on. But that will be subject of a separate post. In the meantime, I'll just show off the two buildings that I can now control with relays. Stay tuned.

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Fun with Signals

Some time ago I took delivery of my first batch of signals. These are generic 3-light signals made in China. They aren't particularly prototypical - the aspects resemble a type of signal used here in Queensland, as well as some European signals. But the looks are very basic. However, for first experiments and wrapping my head around the subject matter, they are more than sufficient.

Out with the Old, In with the New

Ever since I bought my first 'real' digital command system - the NCE PowerCab - I've been thinking and researching about the possibilities of DCC that go beyond running trains and switching points. Subjects like detection, feedback and automation rear their heads as soon as you start diving deeper into the subject matter. And as I did so more and more, I couldn't stop shaking the feeling that my choice of command station was not optimal.