Are Cobalts too big?

Hi Mike

Servos do need a different mind set from other devices.  As you probably know, they came to fame in the model aeroplane field.

Their "home" position is in the centre, and they are deflected right or left.  Controllers can be as simple as the Brunel Hobbies kit, which uses a simple SPDT (single pole, double throw), toggle switch . . .



. . . or the more complicated Tam Valley Depot eight channel DC/DCC device - which is what I use.



Tam Valley Depot 

Tam Valley also make a Frog Juicer, which eliminates the need for switching the frog polarity.

Servos are in their own paradigm, but like DCC, once you become familiar with them, you never want to go back.

Cheers

I've never read so much about servos! There seems to be three or four main suppliers in the UK. I think these guys look the best… A higher initial set-up cost, but the most flexibility and when divided between the 27 points on Chantley, ends up being competitive on price too…

https://megapointscontrollers.com

Hi Mike

That system seems to be very functional.  However, one important function (which it may have, but I couldn't find), is that the servo needs to switch off once the turnout is thrown.  That was one of the big shortcomings of the ESU SwitchPilot.

The gearing of the servo will hold the point rails against the stock rails without the need for the servo to be running all of the time.

Having the servos powered when not actually being moved can set up buzzing sounds.

If you can't find it in the manuals, perhaps a 'phone call to the manufacturer will clear it up.

Cheers

Thanks Max. The unit has a programming feature where you program the start and end of the throw, so the servos can be tuned to exactly the point (!) needed for each turnout. I guess that is the same as 'turning off' the servo…!?

Not really, Mike.  Most of them leave the servos active.

It will be worth the enquiry.

Thanks Max - I've asked the question by email. I'll see what comes back.

Hi Mike,

I think it's in the manual - the end points have to be set for each servo, which are then remembered. £200 for the controllers plus the servos, that's a £300+ system. Looks a good system though with minimal wiring.

Nigel

The end points are programmable, but Max meant actually turning the servos off when they were not moving. I asked the manufacturer and his response was… "I don't turn servos off ever as it's an anti interference measure." So that is interesting…

The cost is definitely high to start with, but with my 25-ish points, I think it works out about similar to ones where you buy individual servo controllers for about a Tenner… I'll keep looking around though as it's a bit early to commit to a decision.

I went through a process of trying several brands and was always disappointed to end up with buzzing servos - no matter how much I played around with the end points.

The Tam Valley Ocotcoder has been the only one which sits quietly.

It's not as functional as some brands, but the main reason I use servos is for the quietness.  Having the odd one buzzing rather defeats the purpose.

I've been thinking some more… If I stick to my current fiddle yard layout, then there will be 27 points on Chantley.

Taking JUST point switching and frog switching (i.e. no switches, control panels, etc.), then costs will be the following PER POINT:

COBALTS: £14-£15
MEGAPOINTS with RELAYS: £16-£17

So what if I just want the simplest possible servo-based point motor? What if I wanted no frills, and to Max's point, also wanted them to turn off?

I am an IT consultant by trade, so I know how to program microcontrollers. A small board comprising a Picaxe chip, servo, relay, and two LEDs for route selection would give me what I want for somewhere between £6 and £9 per point. It would involve a lot of soldering and a bit of programming, but I already have the programming cable…

Hmm…

Still a couple of months away from deciding, but it's something to think about.

PeterMac of this group has purchased the Megapoints Controller

Thanks Ron. I just went and read his thoughts on it, and saw the video of his panel. Nice.