Short Detector (Buzzer)

You’ve just spent 3 hours under the layout adding feeders to your rails. One of the most hated jobs in model railroading is wiring. I don’t get that, I LOVE it. Give me a chance to fire up the soldering iron and I’m in heaven. Well, after your knees have adjusted to standing again, you flick on track power and POOF. Either the breaker trips or your system stops functioning. You’ve got a short.

First, you take everything off the rails, but the short is still there. You check again, yup, still a short. It has to be in the wiring. But which feeder? Your 3-hour job just turned into 6 as you struggle to find the cause of the short. I’m going to show you a simple way to prevent this situation. If you do this, you will immediately be notified of a short as you wire things up so you won’t spend hours trouble shooting.

If you think this won’t happen to you, stop fooling yourself. We all make mistakes and soldering up a red wire instead of a black one is a mistake anyone could make. Having worked as an electronic technician, there is no worse feeling than powering up a device after a repair only to see the magic smoke come curling up. We all make mistakes.

This will cost you next to nothing and you can make more than one so you can throw one in your tool box to take on the go. Speaking of which, this is also useful for modular people. If you connect one of these to the track as you set up, you will immediately be alerted if something is shorting before you power on the track. It works for DC and DCC equally well.

One caution. DO NOT APPLY TRACK POWER while the unit is connected to the track.

I got my buzzer from eBay and it came from China. It took a while but only cost me $1.56 CAD including shipping. I should have bought more than one. If you prefer not to buy from China, there are a couple of Canadian sources that I will provide links for. One is DigiKey, a huge supplier of electronics to consumers and industry and Sayal Electronics, a hobbyist store. While not exactly what I bought, they are similar products albeit a little more expensive, you’re still going to come in less than $10.

What you want is a buzzer that includes a driver, it can be a piezo device or mechanical. Be careful because piezo drivers are all over the place, but you need a circuit to drive them and that adds to the complexity of the project.

To make mine, I simply hot glued the buzzer to a small piece of Masonite, attached a battery and held it to the board with a zip tie and soldered on some clip leads. That’s it! By clipping the leads to each rail and just going about your work, you will immediately be alerted of a short circuit.

Here's a video tutorial I made.