Iowa Scaled Engineering designs, manufactures, and sells many unique and cost effective products intended for model railroad and electronic hobbyists. Explore below for application notes to inspire your designs or browse the store to see all the products we have to offer.

Introducing the CKT-BD1 DCC Block Detector

I’d like to introduce you to ISE’s latest model railroad product – the CKT-BD1 single channel DCC block detector!


The CKT-BD1 – our brand new single channel DCC block detector

This little DCC current-based detector is designed to be highly sensitive while being resistant to false triggering, robust, and very easy to install.  All you need to do is pass one of the bus wires to the block to be detected through the current transformer and provide 5-18VDC to power up the detector.   It can run on as little as 5VDC at 15mA, so it’s perfect for connecting to digital logic such as Arduinos or C/MRI systems.   It has open drain outputs for both detecting and not detecting states, so it’s compatible with a wide range of other model railroad products such as the Modular Signaling System, C/MRI, input modules for systems like JMRI, standalone signal sytems, or even just seeing if there’s something in that hidden section of track on your layout.  It also has adjustable sensitivity, so you can tune it to ignore leakage current through your trackwork while still picking up minute currents from rolling stock.  Precision current measurement circuitry and a little digital microcontroller onboard helps filter the response so that you achieve maximum sensitivity without false triggers.

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Block Detectors – An Epic Tale

The development of ISE’s block detectors has been a fairly long adventure, so much so that the long, drawn-out development cycle through six or seven iterations has become a bit of a running joke between Michael and myself.  It’s served as a bit of a high water mark in terms of design revisions and major overhauls, and every time Michael and I have to rev something, there’s usually a comment of, “well, at least it’s not the !@#$ block detectors again…”

With today’s introduction of the CKT-BD1, I thought it might be interesting to let you all in on how this evolved, and how we arrived where we are today – a rock solid design that I believe in as much as our bulletproof IR sensors.   It’s the sort of thing that no sane manufacturer would do – sort of like running the corporate dirty laundry up the flagpole and waving it around.  But then again, we’re a different sort of electronics company, and Michael’s been arguing for years that I’m not quite sane…

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DCC Auto-Reverser

We were recently asked to build a module that could automatically reverse a locomotive between two end points for use on a small point-to-point switching layout. The idea was to provide a means for continuous running of a train while working on the layout or to break in new locomotives without user intervention.  The end result is described here, with instructions for building your own.  At the current time, this is a mostly a DIY project, but if you want help building one, please let us know.

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Controlling an SDX-1 with DCC

This is very much a “because I could” project, so keep that in mind…  I built the SDX-1 soon after it appeared in Model Railroader in 1991.   It served its purpose, both on my home layout and at several NTrak layouts with which I was involved.  However, it has sat dormant for many years.  A few months ago, I started to wonder what it would take to DCC enable it (it was originally intended to be used with DC throttles). So, with an Arduino and a little code, I now have a sound system that can make an N-scale diesel shake the room (literally!).

Keep in mind that the sound on the recording doesn’t do justice to the low frequency components. It’s much better to hear (and feel) in person.  And yes, there are many other ways (maybe even more practical) to do this.  This, however, was intended more as a fun application and test of the DCC Arduino Decoder Shield than any practical application.

As for the equipment seen in the video, from left to right, there is the SDX-1, an Arduino + DCC shield, a very crude level-shifting PWM DAC (i.e. a single transistor), and the Lenz DCC base station. The SDX-1 is driving the speaker itself (out of view below, sitting on the floor).

Using MRGui on Windows

MRGui is our configuration utility for MRBus based devices.  It simplifies the process of setting the various EEPROM configuration options for each node, using a user-friendly GUI that runs on Windows, Mac, or Linux.  In addition to setting EEPROM configuration options, MRGui can also be used for general purpose programming of AVR microcontrollers.  The instructions below take you through the steps to get up and running with MRGui on a Windows platform.

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Modelling Time Locks on Switches

Time Locks – An Introduction

In the real world, manual switches within signalled territory are protected by devices called “time locks”.  The purpose of these is to prevent a switch from being opened in the face of an approaching train.  When the conductor wants to open the switch, he unlocks it and starts the timer running (how this is done depends on the model of time lock).  The time delay gives any train too close to stop – or sometimes too close to even see a restricting signal – time to safely pass over the switch before the points are changed.  It also triggers the signal system to display restricting aspects around the block, so trains that are further out are alerted to the presence of an open switch.

Once a programmed amount of time has passed, the timer indicates to the user that it has expired (often by a white or green light) and then releases a locking mechanism that allows the points to be moved manually.   (This is commonly done with a locking pin through the throwbar that is retracted, but there are other mechanisms.)

Time locks aren’t just a good idea – they’re required by law here in the US.  Under 49 CFR 236.207, either approach or time locking is required of manual switches in signalled territory.

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Interfacing With ISE’s Fast Clocks

The idea of a clock that runs faster than real time to compensate for the compression in our model world is nothing new.  The idea has been with us since at least the 1960s.  It provides a way to schedule our operating sessions, providing a sense of real time passage and urgency without needing literally thousands of feet of track to represent the vast distances covered by our prototype railroads.  Aside from being a display on the wall, guiding operators’ train movements, fast clocks have remained an isolated system, our model world unaffected by the passage of scale time.  Think about all the things in our daily lives that are linked to the time of day and you’ll quickly realize how odd that is given all our other technological advancements, and how much potential is in that idea.  I believe fast clock integration is one of the huge, unexplored areas left in the hobby today for added realism.

In this article, we’ll show you how to build an inexpensive device that allows you to synchronize items on your layout to fast clocks by using MRBus, the networking protocol that connects the Iowa Scaled Engineering Networked Fast Clocks, in conjunction with the popular Arduino prototyping environment.

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