Motorising a Mamod point

A very popular starting point for Live Steam. With their low cost comes a number of problems which can be discussed here
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dave3054
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Motorising a Mamod point

Post by dave3054 » Sun Oct 08, 2017 1:45 am

Hi All
Has anyone tried to motorise a mamod or mss point?
I want to remotely operate points on my railway, maybe using a servo.
Any suggestions guys?

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tom_tom_go
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Re: Motorising a Mamod point

Post by tom_tom_go » Sun Oct 08, 2017 8:41 am

This can be I am sure as I have used cheap servos for Peco points.

Can you take a picture of the Mamod point you have so we can see the best way to do this.

Also, will the point be on ground level or raised track?

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Re: Motorising a Mamod point

Post by dave3054 » Sun Oct 08, 2017 9:53 pm

MSS Point.jpg
MSS Point.jpg (411.03 KiB) Viewed 8355 times
This is the point in question. Its the MSS version of the Mamod track point.
As you can see it is off the ground by 2 feet.

What do you think?

Cheers
Dave

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Peter Butler
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Re: Motorising a Mamod point

Post by Peter Butler » Sun Oct 08, 2017 10:50 pm

Hi Dave, in answer to your question, ..... yes it can be done. However, if your question is... Is it a good idea?..... then my answer would be, no!
Outdoor layouts are exposed to all weather conditions, electrical systems prefer dry ones. In order to operate your points with servos you need water resistant ones as used in model boats, you need switches to make them work which must be waterproof if located outdoors, you need a transformer to a provide a voltage compatible with your servos and finally you need a mains supply from your house or shed. If you think you can provide all of these then go for it.... I fitted about ten on my railway and immediately ripped them all out again.
My preferred solution was to fit either rod or wire-in-tube control systems with the levers placed in convenient locations around the layout. I found that I was often in the wrong place when a point needed changing and having a central control panel inside my shed was a real pain. Like your railway, mine is also raised on boards so access to the underside is easy enough to fit concealed WIT. It is also cheaper to install and needs little or no maintenance.
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I have a rod operated point about 4m away from its lever and WIT ones reaching more than 2.3m. Bicycle brake cables I find are most suitable for this.
I hope this is useful information despite the fact it isn't what you wanted to hear.
The best things in life are free.... so why am I doing this?

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Re: Motorising a Mamod point

Post by dave3054 » Mon Oct 09, 2017 12:57 am

Hi and thanks for your detailed answer.
I have used a similar system on my oo gauge garden railway using mercontrol lever frames.
I was hoping to simplify things as I have all the servo control systems that are self contained and run on 4.5 volt batteries.
All that said there is a certain satisfaction of pulling a lever to throw a point.
Let the experimentation begin :D
Cheers
Dave

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Re: Motorising a Mamod point

Post by ge_rik » Mon Oct 09, 2017 9:34 am

Hi Dave
If you did want to experiment with servos, Hobbyking do a reasonably priced 'waterproof' servo (£3.59). I've not had a chance to try them out in the garden as yet, so no idea how waterproof they are, but if it was beneath the baseboard then it might survive outside OK.
https://hobbyking.com/en_us/hobbykingtm ... tore=en_us

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Re: Motorising a Mamod point

Post by tom_tom_go » Mon Oct 09, 2017 11:45 am

You don't need waterproof servos if the line is raised and you place them underneath the trackbed.

I use the Tower Pro SG90 servos and they are all mounted using plastic angle and standard wiring, no water proofing required:

Image

They run off a battery pack so no mains supply is needed.

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Re: Motorising a Mamod point

Post by dave3054 » Mon Oct 09, 2017 11:51 pm

Hi all
Your comments and advice has given me much food for thought.

I am going to try and go for a hybrid system, where a servo mounted under the board operates the point via a rod in tube. I am also using the SG90 on my oo gauge indoor layout, I must admit I have had little problems with them. I will get some of the hobbyking servos to compare.
With a good weekend forecast I'm going to give it a go. I will report back soon.

Cheers
Dave

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Re: Motorising a Mamod point

Post by tom_tom_go » Tue Oct 10, 2017 7:52 am

As you use Deltang you could R/C it as well.

However, if the point only needs to be set a certain way you can just spring load it to reset each time?

I do this on a run a round loop I have where I use just wire under the points to spring them back into position each time.

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Re: Motorising a Mamod point

Post by pandsrowe » Tue Oct 10, 2017 10:11 am

Tom, I'm intrigued by your method of operation using the SG90 servo and battery power. Would you be so kind as to explain how you actually do this as I was always under the impression that one needed some kind of fancy electronics to convert the battery dc into pulses that the servo would recognise, but then what do I know?
Phil

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Re: Motorising a Mamod point

Post by tom_tom_go » Tue Oct 10, 2017 10:25 am

pandsrowe wrote: Tue Oct 10, 2017 10:11 am Tom, I'm intrigued by your method of operation using the SG90 servo and battery power. Would you be so kind as to explain how you actually do this as I was always under the impression that one needed some kind of fancy electronics to convert the battery dc into pulses that the servo would recognise, but then what do I know?
I use an Arduino device with code to control the speed and position of the servo movements using the pots on Deltang Tx as on/off switches.

However, you can achieve what you want to do using a 555 timer circuit which is easily built and there are loads of examples online.

If you need help let me know.

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Re: Motorising a Mamod point

Post by ge_rik » Tue Oct 10, 2017 11:13 am

Or if you want a low tech hard wired solution, you could always use a servo tester
Eg http://www.ebay.co.uk/itm/201806519921

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Re: Motorising a Mamod point

Post by pandsrowe » Tue Oct 10, 2017 4:44 pm

Thank you both for the explanation, it's given me food for thought and a possible winter project experimenting. I was going to use Bowden cable to acctuate some points on my forthcoming railway extension but I'm quite liking the look of this hi-tech approach. Do you think that I would potentialy suffer with any voltage drop driving servos from a distance of around 5 metres?
I've had a very quick look online and I can't believe how cheap some of these servos and testers are, obviously depending on where one buys from.
Phil

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Re: Motorising a Mamod point

Post by ge_rik » Tue Oct 10, 2017 7:14 pm

pandsrowe wrote: Tue Oct 10, 2017 4:44 pm . Do you think that I would potentialy suffer with any voltage drop driving servos from a distance of around 5 metres?
I've had a very quick look online and I can't believe how cheap some of these servos and testers are, obviously depending on where one buys from.
Hi Phil
You might get away with a five metre run (see https://forum.pololu.com/t/max-servo-wire-length/505 ) , but you might have to increase the gauge of wire to help prevent voltage drop. You might also get some interference with the servo signal over such a long run - but you could try using screened cable to see if that makes a difference.

Best thing to do is experiment and let us know how you get on.

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Re: Motorising a Mamod point

Post by dave3054 » Sun Oct 15, 2017 10:03 pm

Hi Guys
I have had a go at servo control of my mamod point. As it is all metal it needs a fair push and pull to throw it.
I remember reading on another forum that one chap used a car central locking servo.
One is on order from that on line auction site @ £3.50 each.
It should arrive soon so Ill report back once testing is underway.

Cheers
Dave

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Re: Motorising a Mamod point

Post by dave3054 » Sun Oct 29, 2017 3:56 pm

Hi all
I have now recieved the car central locking servos.
Big, chunky and waterproof. I fixed a new point to a test board with the servo at 90 deg to it.
After a minor adjustment the servo changed the point every time.
I will be mounting the servo under the base board when I install it outside, but that can now wait for next season.

I have used a two wire central locking servo. Reverse the polarity of the two wires to alter direction. It runs on 12v dc.
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I hope this gives food for thought. These servos cost around £3.50 each.

Cheers

Dave

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