Auto Direction Change

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Julian Roberts
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Auto Direction Change

Postby Julian Roberts » Sun Feb 28, 2010 12:05 am

Sorry if this is naieve question. It's only P4 specific because of the 3ft 6in minimum radius I use. I want to run in and test locos. I've no room for a 7 or 8 foot diameter circle, but it's easy enough to have a metre or two of track with the vehicle running backwards and forwards a few hours at a time - if I can have it reversing automatically at each end, preferably 'softly', i.e. gently.

Yes, I could get a 'rolling road' but I'd prefer to have a more real life test.

So is there a way of creating this auto direction change electonically? Or do I need to get sensors that work from Infra Red or whatever? I am not using DCC. This is straight forward DC.

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Paul Willis
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Re: Auto Direction Change

Postby Paul Willis » Sun Feb 28, 2010 8:12 am

Julian Roberts wrote:Sorry if this is naieve question. It's only P4 specific because of the 3ft 6in minimum radius I use. I want to run in and test locos. I've no room for a 7 or 8 foot diameter circle, but it's easy enough to have a metre or two of track with the vehicle running backwards and forwards a few hours at a time - if I can have it reversing automatically at each end, preferably 'softly', i.e. gently.

Yes, I could get a 'rolling road' but I'd prefer to have a more real life test.

So is there a way of creating this auto direction change electonically? Or do I need to get sensors that work from Infra Red or whatever? I am not using DCC. This is straight forward DC.


Hi Julian,

This is only *half* an answer I'm afraid. I've definitely seen something out on stands at shows that does something like you ask. I'm not sure if it's DC or DCC, but I expect it's DC. So there is a product.

The problem is of course that such a thing never interested me so I can't recall what I was looking at. However it was most probably a "Gaugemaster Super Shuttle" unit. The website says "A time controlled unit which can be used with any controller and stops a locomotive at a point on a line, reverses it and then stops it again at a second point, reversing the locomotive again. This repeats indefinitely. The duration of each sequence can be adjusted from approx 20-70 seconds."

There is a download of the instructions at http://www.gaugemaster.com/instructions/ss1.pdf

Yours for 27 quid, or a couple of Maggies less if you go to the box-shifters in the front of the magazines.

HTH
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

chrisf

Re: Auto Direction Change

Postby chrisf » Sun Feb 28, 2010 7:30 pm

In case anyone is puzzled as to the expression "Maggies", it is the name given to the pound coin when it was introduced in the PMship of Margaret Thatcher - it is thick, brassy and thinks it's a sovereign. Flymo, I salute you!

Chris

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Julian Roberts
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Re: Auto Direction Change

Postby Julian Roberts » Sun Feb 28, 2010 11:25 pm

I already have an answer to my own question from All Components who were here in Glasgow today at "model rail scotland". I remembered them selling something based on sensors, but they were able to sell me today some circuitry gizmo for 29 Maggies that exactly does the job.

Thanks for the thoughts already posted, and a bit of Maggie education. If I've anything to say of interest I'll post my thoughts about how it works when I've set it up.

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Julian Roberts
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Re: Auto Direction Change

Postby Julian Roberts » Thu Mar 04, 2010 8:41 pm

In case anyone is interested in more information, the reversal mechanism "Automatic Shuttle and Loop" that I bought from All Components is based on a Light Dependent Resistor. This little thing about the thickness of a pcb sleeper sits between the rails at the point where direction change is desired, and the action of the train passing over, covering the resistor and thereby decreasing the light hitting it, actuates the system. One is put at each end of the length of track. You connect it all up to a little block of electronics, which also needs a 12V DC supply, plus power from your controller 0-12V DC. I am still in the process of doing all this.

This gizmo can be set up to do four other similar functions: Shuttle with Intermediate Stops; Shuttle with Sidings and Intermediate Stops; Reversing Loop with Intermediate Stops; Loop with Stops.

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Julian Roberts
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Re: Auto Direction Change

Postby Julian Roberts » Sat May 01, 2010 4:11 pm

A correction to my last post. While the 0-12V DC power from a layout contoller (which controls the loco that you're running in or whatever) is no problem, the 12V DC supply input needed to power the actual electronics is not adequately supplied from another layout controller on full power. It has to be a "regulated" supply. I had to get back to All Components who explained I needed to buy for a further eight quid or so their gizmo, a "Conversion Board", to convert 16V AC to 12V DC, to get the regulated supply. It arrived the very next morning, thanks to our still wonderful postal service.

From then on everything has worked fine. The settings for the Light Dependent Resistors have to be adjusted according to ambient light levels. All that I have had to learn is that the LDRs are very light sensitive and respond differently to changing levels of daylight. The settings may have to be adjusted if an overcast day turns into a bright sunny one. Running in unchanging artificial light obviously gets round that very minor issue.

All in all a very satisfactory outcome to the problem of running in a loco in a confined space.

craig_whilding

Re: Auto Direction Change

Postby craig_whilding » Sun May 02, 2010 1:37 am

For DCC users its worth noting that Auto Shuttle functionality is built into Lenz Silver and Gold decoders under the 'ABC/asymmetric DCC' feature, You just put 4 1A diodes (3 one way, one the other) at each end of the track.

For initial testing of kit builds though I stick to the DC controller and Bachrus Saddles.


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