May 2019 - Using stepper motors to operate model rail turnouts
After being a bit disappointed with both my muscle wire and servo experiments to operate turnouts, I started doing a bit of research on linear actuators. While most were very expensive, I eventually stumbled on some at AliExpress by searching for the term ‘Miniature Slide Screw Stepper’ or ‘linear stepper’ and various combinations of similar words. They looked ideal so I bought some, similar to these:
May 2018 - Using muscle wire to operate model rail turnouts - updated from my old blog
This now happened quite a while ago now but as luck would have it, barely a week after I made my last post on using muscle wire for turnout actuators my last bit of wire broke :-( It was a bit of a shame really, as the test rig had operated for months without any problems.
What happened was that I built an actuator based on the crank system as described in a previous post on servos and at Tamalpais Valley Railroad, but instead of using a servo to move the crank I reused my last bit of muscle wire to pull on one side of the crank and a spring on the other side to pull the crank back. I used a small piece of styrene with 3 holes in it to connect the muscle wire, the crank and the spring:
May 2018 - Using muscle wire to operate turnouts - updated from my old blog
Well I know I haven’t posted much in a while, but rest assured there have been exciting developments going on over here on a number of fronts.
The first thing is, I am gradually becoming convinced that I may have ‘cracked’ the holy grail of finding a cheap turnout actuator for my layout. My last couple of posts have looked at using servos, and they show a lot of promise, however I have been experimenting with something better - muscle wire.
Now, truth to tell, I have thought of using muscle wire - Nitinol wire - for a long while now. I bought a wire sample kit and book nearly 10 years ago and have off and on (mainly off) tried to actuate turnouts using various mechanisms. I have a small drawer of ‘experiments’ gone wrong as you can see here (note the fried resister in the experiment at the top):
Apr 2018 - Using rc servos to operate points - updated from my old blog
I’ve been working on low cost ways to control turnouts. I bought some servos (AU$7 for 4) on eBay and tried to operate my hand made turnout with one of them. Here is a picture of the initial setup:
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