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Point Motors

15647 Views 53 Replies 14 Participants Last post by  steamrailuk
N Scale:
Point motors are my frightener and always have been. They are big, noisy and power hungry, but most they are expensive. Not when buying one or two but when buying 30-40 or more and one doesn't even get to see them, under the board. If you want something simpler and neater on top the price doubles. There rarely seems to be more than a penny or two discount for quantity.

This is probably a stupid post but I have wracked my brain trying to find an alternative. I cannot believe that nobody has found an answer to one point one solenoid.
It is easy for one switch to operate many, but not the other way round. It spoils the cost estimate prepared for the wife, when one forgets to factor the solenoids in...

Has anybody come up with anything at all, other than finger pressure.

Yes; I know I am leaving myself open here.
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Hello all, I decided to take up the challenge here and provide hopefully enough of an idea that then anyone who is actually serious about exploring electro-mechanical point control using just one point motor can actually get on and do something.

Concept is taken from a turntable with indexing to align a point motor with its appropriate wire in tube partner. I have shown 5 but if you really want to do 40 I can see no problem with that either.

Hopefully the plan view sketch (5 seconds work) will make the idea / concept fairly plain to see.

The LEDs shine up from under the disk and through the hole only when the hole is aligned over the correctly lit LED. This means that when you make Wire in Tube (WIT) target number 2 (press button, DCC, PC, whatever) this sets the motor off rotating the disk until the hole falls over the LED and the light shines through and hits the Light dependant resistor thus cutting the motor drive circuit. This has aligned on the opposite side a point motor of some sorts ( I have shown a coil / solenoid type but if it is only one it could even be a Tortoise and still remain at the GBP40 budget). I trust this makes some sense. Go and build it and report back I say
The target size and shape can be adjusted for any innacuracies in the LED/LDR combo.

PS, to save even more money you could mount the LDR directly over the hole on the disk saving on LDRs.
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Nice one Richard. I knew there must be a memory wire solution however I got stuck on the 40 units side of thing.

Well Donone, over to you now to run with it I reckon as there is enough conceptuals here to actually provide exactly what you asked for in your first few posts - single mechanism point control for 40 points at less than AU$2.50 per point. Time to get building hey?
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Wiggy, Its all ok, I'm an engineer too - doesn't mean a thing I've discovered. Most of the good ideas in my house come from my wife - and I will continue to credit them in that way too (if I know what's good for me!)
I was thinking of using these but coupled with a memory wire actuator (which is actually quite inexpensive actually) and then you have a quality point motor I reckon which is totally silent, robust and also repeatable across multiple installs.
Too kind, it was minutes of thought only, needs more refinement and I think that a hybrid of Richard's idea would be the best solution however a total memory wire solution could well be the go.
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