Using stepper motors to control the semaphore signals
used with model railways

In modern railways semaphore signals have mostly given way to coloured-light signals, or no signals at all, at least those at the side of the track. But in the model railway world there is a desire to include semaphore signals since part of the attraction of the hobby is the ability to show the way things were.

This article follows on from that by the late Andy Flind, PIC Quickstep (June ’04), which gave a very good introduction to stepper motors and the means of testing them. Here a specific application for stepper motors is described, using them to control the movement of semaphore signal arms.