Megapoints Controller (Point Servos)

[TimberSurf]

When I first saw Peco had introduced a servo controller for point control, I got excited! .......until saw the price! (£12.50 ea point)

I recently discovered the possibility of using Arduino (cheap) nano boards that can be programed to be a controller(£2.50 drives 4 points), but this means some programming (learning curve), soldering and an interface circuit. Although this may still be the cheapest option prorata, the answer could be this http://loolee.org/megapoints/index.html
at £50 per 12 (£4.17ea) its not a bad price and is way easier than developing your own (works out of the box)

Edit: As the product is so successful, the owner now has to charge VAT, so is now £60

[Suzie]

It is a cheap system if you have a lot of points in one area, and you don't need to switch live frogs. Looks like it might be based on an Arduino.

[cowjam]

Arduino is cheap and scalable. Using shift registers you could control as many points as you wanted, but the programming and circuit become more complicated.

I came to this hobby from arduino - I'm (very slowly) building an arduino controlled railway.

[TimberSurf]

I am finally at the point (pun intended) that I am laying track again on my new railway. I am convinced megapoints is the best option with servo's, so I am now developing a mechanism to hold the servo and give local switching. The first attempt included some 10x35 wooden batten with a hole routed in it to accomodate the servo, two microswitches mounted on the top of the wood and peice of wood at right angle to mount with. The fulcrum point for the 1mm piano wire was an issue, too sloppy and will wear over time. I decided to make the head of the tee with aluminium and screw to the wood, but realised it would just be simpler to make the whole thing from metal. A lot of research later and I have found some right angle aluminium bar that is just the right size, some "off the shelf" brass spacers to offset the servo from the face and the design is nearly done! Servo, two microswitches, piano wire, 2 types of screws and the alumminium will total £1.89 per point!
So £2.50 for Megapoint and £1.89 for parts (+20p for servo harness) = About £4.60 per point!

3D conceptual Model

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Watch this space for the pictures of the actual, soon! [just waiting for china to deliver!]

[TimberSurf]

It is a cheap system if you have a lot of points in one area, and you don't need to switch live frogs. Looks like it might be based on an Arduino.

Thats why I am developing a reliable frame to hold the servo so that two microswitches can be added for live frogs/mimmic/signals

[TimberSurf]

OK so some progress, most parts now in stock, production can begin!
I bought two Megapoints PCB's the other weekend, so no excuses now I have something to drive them with! A fair amount of track is down so I can start mounting the servo's to the points soon.
Some close ups of my bracket, showing the duel microswitch's with servo cables soldered on for fast connection/disconnection in the future.

The production line

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[Gordon H]

You seem to have used additional servo cable ends for your microswitch connection flying leads, which is of course a reasonable thing to do on the face of it. However, I would have suggested you use the opposite gender arrangement for the microswitches compared to the servos, to prevent the possibility of misconnecting a microswitch into a servo drive output, which probably won't do the driver circuit much good.

[TimberSurf]

Gordon
I take your point, but as an Electrical Designer, if I get that wrong, I deserve the smoke!
I may not stick with servo connectors on the microswitches, as it does not lend itself to connecting to the 3 free wires from the track for electrofrog, I don't want to end up soldering under the board, so need to find a connector to ease the job cost effectively, watch this space!

[Gordon H]

Gordon
I take your point, but as an Electrical Designer, if I get that wrong, I deserve the smoke!

I was thinking more of situations where fumbling with flying lead connections underneath a baseboard might result in an inadvertent mis-connection.
Given that it is common to sacrifice a servo extension lead to make this sort of extra connection anyway, you have the option to choose either gender.
On a self-contained servo point motor design I am working on, I deliberately use a reverse gender servo connector arrangement for the motor enclosure cable end to prevent the possibility of someone else mistakenly plugging a bare servo into the associated layout cable end.

[TimberSurf]

Not going well! The Chinese "tower" servos are very rough. Only getting 50% that work well!
May have to invest in some HobbyKing servos!

[TimberSurf]

Update, cheap Chinese ain't as bad as I thought!
A voltage converter arrived today, so I can feed accurate 6V to my servo tester, previously I was using 4.5V from a battery pack, the difference is substantial, servos that were struggling to 'make' the micro switch are now flying, with no "stutter"
I can now quality check all my mechanics and get my production line up and running again!
I will tilt the baseboards on their side and fit all the servo's this weekend hopefully

[TimberSurf]

Spent a large part of weekend installing the servos under board, luckily I can turn over, so not a back breaker. All eight installed and wired, except for the Electrofrog, that and engine testing will have to wait until next weekend

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And a temporary Panel to control them (Proper aluminium faced box to be made later)

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[ElDavo]

Neat and simple mounts for your servos. In the first photo it looks as if one of your solder joints on the left-hand microswitch has popped!

Cheers
Dave

[TimberSurf]

Neat and simple mounts for your servos. In the first photo it looks as if one of your solder joints on the left-hand microswitch has popped!Dave

Dave
I left that as the "let's see if they spot the deliberate mistake"
It was like that weeks ago and was my test servo, so got a battering, will fix later, as its just 2x M2 screws and yank the connector and its on the bench for repair!
I will use the other one for eloctrofrog, the second will be for detection (block control and signalling), but that is years off just yet

[TimberSurf]

For those that are interested, I only need two micro switches, one for electro frog and eventually one to give indication, supply to multiple common supply locations as below

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