Servo Controlled Points

  • Thread starter Thread starter GAP
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GAP

GAP

G Scale Model Trains, 1:1 Sugar Cane Trains
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I saw this project on Trainelectronics by Dave Bodnar Simple Servo Controller

Having one of the servo testers and some servos I decided to see if I could adapt it to my outside layout.
I have made a mock up of the controller and after a bit of experimenting in the shed with a test bed I put 2 servos out on the layout next to 1 set of LGB points and 1 set of Aristocraft points to see how they will go when I run a train through them.
If successful I will convert all my points to servo control.
I plan to put the controllers into a weatherproof enclosure and put a signal box over the top to disguise it.
My biggest worry was that the distance between the points I want to control and the controllers might be too large and the signal would degrade.
I made a 12 Ft long test cable and successfully changed a set of points over that distance.
As I have 2 signal boxes I will split the 12 sets of points I have into groups of 2 (6 controllers in each signal box).
The control switches will be weatherproof ones and mounted in enclosures with a lid.


Edit;
As the servo tester has outputs to control 3 servos at the same time, I have come up with the idea of using a second servo to move a semaphore signal so I can see which way the points are set at a glance.
I tested the idea on my bench set up and the second servo moved in time with the point driver.

Pictures of my test set up.

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Merged_document (1).jpg
 
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Servos appear to be the thing for point control these days, issue for me is the wiring. Whereas a standard setup requires only 2 wires per point or pair, servos have to have 3 wires. Can be a real issue with a big layout. Have been dabbling with them in my 00 layout and they appear to work just fine, now I have to install them just 7 points but all the previously done point wiring to redo. Already been delayed by 2 years!
 
dunnyrail said:
Servos appear to be the thing for point control these days, issue for me is the wiring. Whereas a standard setup requires only 2 wires per point or pair, servos have to have 3 wires. Can be a real issue with a big layout. Have been dabbling with them in my 00 layout and they appear to work just fine, now I have to install them just 7 points but all the previously done point wiring to redo. Already been delayed by 2 years!
Click to expand...

I am running a bus right around my layout; 12V and 5V for accessories (building lights, signals, point control etc) so I really only have to assign a wire for the servo signals but as I am using multi core sheathed wire I can have as many wires as I want just have to have breakout boards.

The advantage I have is that I am starting from scratch not retrofitting an existing wiring config, so I can build in expansion for the future, for example I could use either Raspberry Pi or Arduino I/O ports instead of mechanical switches. The issue with using those is programming them (I am learning the Python programming language online at the moment) and a display that can be used in sunlight ie an old tablet/phone but overcoming the challenges that is part of the attraction, but it may never happen who knows.

I could by off the shelf (a standard setup) but there is no fun in that; plus the expense makes it nonviable, this is a poor mans way of overcoming that plus I have the skills.
Not everyone's cup of tea but another way that will work for me.

I also have a HO layout which uses solenoid point control and I will not be changing that even after converting it to DCC.
 
GAP said:
I am running a bus right around my layout; 12V and 5V for accessories (building lights, signals, point control etc) so I really only have to assign a wire for the servo signals but as I am using multi core sheathed wire I can have as many wires as I want just have to have breakout boards.

The advantage I have is that I am starting from scratch not retrofitting an existing wiring config, so I can build in expansion for the future, for example I could use either Raspberry Pi or Arduino I/O ports instead of mechanical switches. The issue with using those is programming them (I am learning the Python programming language online at the moment) and a display that can be used in sunlight ie an old tablet/phone but overcoming the challenges that is part of the attraction, but it may never happen who knows.

I could by off the shelf (a standard setup) but there is no fun in that; plus the expense makes it nonviable, this is a poor mans way of overcoming that plus I have the skills.
Not everyone's cup of tea but another way that will work for me.

I also have a HO layout which uses solenoid point control and I will not be changing that even after converting it to DCC.
Click to expand...
Blub blub blub. So I could use my existing wiring and just run one new wire to each servo! Oh joy that is a much simpler project. Glad I never........no that will not work as I am using a Megapoints Controller and the pins from the point port are 3. But I may get some saving lots of thinking and working out to do. Another 2 years delay likely!
 
Paul M said:
Trouble is that in 2 years time therewith be an even cleverer way of doing computer things
Click to expand...
Oh yes please perhaps with Air operation and just 1 pipe to each point or pair, now that is the way to do things.
 
So I just need a supply, a receiver, an activator, a throw, pipework including unknown joints, simple if installing in a new set-up :)
 
Settle down folks!!!
I was just showing what I was doing; not trying get people to rip up their existing systems and switch to another one.
 
GAP said:
Settle down folks!!!
I was just showing what I was doing; not trying get people to rip up their existing systems and switch to another one.
Click to expand...
Oh, and there was I thinking .............................. :rock::rock::rock::rock::rock:
 
Now that the dust has settled, which servos are you using? Is the type critical or can anything close to it work?
 
FatherMcD said:
Now that the dust has settled, which servos are you using? Is the type critical or can anything close to it work?
Click to expand...
Most probably these one as they have metal gears and hopefully should be more robust.

MG90S – Metal Gear Micro Servo Motor

MG90S – Metal Gear Micro Servo Motor
components101.com components101.com

I conducted my testing with some with a 1.5Kg/cm torque and they work just fine I also used some physically bigger ones.
The smaller ones have a slight buzz when at one extreme while the larger ones did not so I should probably investigate whether that is critical or not.
 
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dunnyrail said:
Whereas a standard setup requires only 2 wires per point or pair, servos have to have 3 wires.
Click to expand...
MD Electronics makes a servo driven switch motor with an integral DCC decoder that will also operate on an analog input. I finally got the ones I ordered a while ago. Only two wires are needed because of the decoder. I did check one straight out of the box with 9V DC (9V battery). It appeared to operate fine. I then mounted one on a LGB R5 turnout to see how well it would work on the bench, again using a 9V battery. It worked perfectly. The throw did not need to be tweeked. The points pushed solidly against the stock rails. I'm not sure how these switch motors will work "out in the wild" but I'm impressed so far. The only drawback is that they will not accept a LGB points lantern without some adaptation. Pics included.

MD servo - 1 (2).jpeg MD servo - 1.jpeg MD servo - 1 (1).jpeg MD servo - 1 (3).jpeg

Edit added: I should mention MD Electronics also has a decoder/servo kit to replace the guts of LGB EPL switch motors. It uses the existing LGB housing and throwbar.

Second edit added: You don't need to run any wires if you're using DCC! Just program the switch address and attach the two leads to the track.

Third edit added: A second potential drawback is that a derailment is almost certain if a train is run backwards against the points unlike LGB EPL point motors where the points will be pushed aside. But this is true for many different point motor/operating mechanisms.
 
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phils2um said:
MD Electronics makes a servo driven switch motor with an integral DCC decoder that will also operate on an analog input. I finally got the ones I ordered a while ago. Only two wires are needed because of the decoder. I did check one straight out of the box with 9V DC (9V battery). It appeared to operate fine. I then mounted one on a LGB R5 turnout to see how well it would work on the bench, again using a 9V battery. It worked perfectly. The throw did not need to be tweeked. The points pushed solidly against the stock rails. I'm not sure how these switch motors will work "out in the wild" but I'm impressed so far. The only drawback is that they will not accept a LGB points lantern without some adaptation. Pics included.

View attachment 281912 View attachment 281913 View attachment 281914 View attachment 281915

Edit added: I should mention MD Electronics also has a decoder/servo kit to replace the guts of LGB EPL switch motors. It uses the existing LGB housing and throwbar.

Second edit added: You don't need to run any wires if you're using DCC! Just program the switch address and attach the two leads to the track.

Third edit added: A second potential drawback is that a derailment is almost certain if a train is run backwards against the points unlike LGB EPL point motors where the points will be pushed aside. But this is true for many different point motor/operating mechanisms.
Click to expand...
Tried to find them to get a view of supplier and price with no luck, can you post a link please.
JimmyB said:
So I just need a supply, a receiver, an activator, a throw, pipework including unknown joints, simple if installing in a new set-up :)
Click to expand...
Well Jimmy I have installed air in new and old layouts and it is the simplest but let us discuss that on a different forum.
 
GAP said:
Settle down folks!!!
I was just showing what I was doing; not trying get people to rip up their existing systems and switch to another one.
Click to expand...
My apologies GAP, I did mean to disparage what you were doing, it's just that everything in this world of electronics and computers moves far too quickly for me.
 
I've tried using one of those servo controllers to make a servo operate. No matter what I did, nothing happened. I hooked it up just like it is shown in,

 
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