Modifying a Dapol OO motorised signal.

First off, I’ve not started yet, it’s something I’m working on..

but has anyone here done one already and converted to servo power thus giving it a defined on/off when required by setting rather than the random push button it was designed with?

my reasons for thinking of changing to servo is a quicker, quieter and smoother control that offers the bounce (which Dapol’s own motor doesn’t give)

I’ve found this video on YouTube of the guy from Megapoints Controller who has done this.



not sure which is easier, modify one of these or modify a Ratio signal and somehow fit an LED.

The other idea of having a servo is that the arm could also operate some micro switches to then dummy up to the new signal repeater I’ve acquired.

Andy

 

Interesting suggestion.. I’ll have a look at that!
Andy

 

THe SMS one doesn’t appear to do bounce,

However. I think I can do that on the Ardunio board.

Watch this space as the saying goes.

 

Right, we have a plan. I have found someone on Ebay who has already designed and prints a Servo mount for two contact switches, so said mount and switches have been ordered, I already have the servo.

Having watched the video, my intention now is to see what I can do with the Dapol signal to keep it removable from my board (just in case we go to another exhibition, but frankly, its looking rather unlikely in this day and age, where by the signal can be connected to the servo.

here is what we have ordered so far.

the design for the bracket demonstrated with the switches.


and without, showing how they can be adjusted to suit.

And two of these switches. I opted for the loony arm rather than the roller versions.

The plan will be to place the servo in as designed, I'm hoping I can use one of the + shaped arms but chop the top and one side off leaving the bottom end to hit the contacts and the shorten the remaining side arm to move the rod for the signal arm - if all else fails, I can disconnect the wire in to the servo arm if I need to take the signal off. I will then look at adding a small plug for the light feed and wire it in to the current lighting circuit of the layout (probably where power is coming from now)

 

I’m thinking of the servo working off an Arduino board Writing my own scripts re throw as bounce etc.

The lamp can be powered by its origins wires extended and plugged in to ,y current lighting circuit on the layout. The repeater only needs 1 AA battery to work, so can be on its own circuit,or what may be a better option is also power it off the light power circuit and then it goes off with the layout and the needle moves to wrong.

The actual “signalling” is likely to be a dpdt using just one side or a spdt switch

 

It’s annoying that I can only post a video here that I’ve uploaded to YouTube..

but, sat last night and did a dry run with the items. Needless to say, the servo does what it should at the moment, but on a potentiometer.. (this is V1 after all) but having sat for an hour puzzling over which of the 6 contacts over the two switches needed wiring to what, I did get the servo to trigger the signal repeater with the “wrong”
Setting coming up whilst the servo traverses from one side to the other.

I have put in the beginning wire diagram for the arduino that will drive it.


The wiring is temp, so will make more permanent later and much tidier. I may make a mod to the top of the plastic to allow the original signal screw thread to drop in through the top and the nut that secures the signal to the base board sit above the servo and hold it all together.. I will post some photos of the signal soon to explain this more.

 

Ah. Well that plan is scuppered.

here is the bottom of the Dapol signal. The black part is threaded and where the nut is - is about where it needs to be to secure to the baseboard.

The remaining thread would be too long and clash with the top of the servo, which wouldn’t be an issue as can always trim down the threaded part.
But..


As you can see at the top, the servo box has side walls, and they are too narrow to accommodate the nut so couldn’t lock it it off.

I am now considering if I could print my own narrower bottom as it will only need to pass two wires for the lamp and the signal wire. That or I go back to the guy who made this to see if he can design me a bespoke one that is wider?

on another note, I have noticed the actual signal is missing the balance weight at the lower part of the signal post.. shame.

 

https://youtube.com/shorts/i0y1RtxQvus?feature=shared

Here is where we are at this far.. but for some reason I can’t embed this video.

andy

 

And after some soldering and one burnt finger!!

https://www.youtube.com/shorts/a9GPyuPrVL8

 

I’m curious if it’s because YouTube uploaded them as “shorts” ? Got me stumped.

but thank you.

 

I have now moved on to the next stage - taking the signal apart.

As is, from the front and side (like a custody shot! lol)
Sadly, the one thing that strikes as missing is the balance weight at the bottom. Now that would have looked great animated - and actually, it could help as the use of levers here could mean that one wire connects here and the new wire to the servo and also varying proportions. (Ie I can have a bigger throw of the servo arm compared to the small movement that may be required..

now to the inside, looks like Dapol use a motor to drive a worm gear moving the rod up and down.


opened up.

close up. I will removed the circuit and motor. Means I will loose the spring, can’t have everything, although I’m not sure it will need one. What I do need is a small bit of new rod for the signal rod.

 

Due to birthdays and going London last Saturday and then back for 2 evening and 2 night shifts not much has progressed…. Although…

I have been working in the sketch side, but again I’ve had a few issues. It looks like I may either have a faulty servo or I have a 360 servo rather than a 180. Now I have never heard of the difference, but apparently the 180 will only turn through, yes, 180 degrees. So the potentiometer inside that feeds back has a limit. A 360 is obviously different and can go full circle and the rest.. and that’s what mine is doing.


here is the demo where we show three parts of the build. The first part has shows it working on a variable resistor to make the servo move and trigger the switches, then demonstrating the first part of automation with a servo sweep. The last part shows it working on the final sketch code, but for some reason it just goes around and around and around and
Around and around and…

hence why we think it’s faulty or a 360.
So that’s where we are at. Awaiting a new 180 servo in the post, and then once that’s all working as it should I’ll start the signal side.

 

I don’t have a scope. Only a volt meter.

I have spoken with the guy who part wrote the sketch and had my head bitten off by saying I’d not listened when he told me the servo was wrong (suggesting there was nothing wrong with his sketch) so who knows..

see what happens with the new servo when delivered. And then I can go back to him
And see what he has to say.