Using servo's to switch points with RM

[Padders]

Hi

Has anyone managed to replace soleniods for servo's such as Towerpro SG90, to switch points using e-link?

Any feedback appreciated.

Martin

Mod note - as eLink is associated with Railmaster you post has been moved to that forum.

[P-Henny]

Not that I have done it, but you need an accessory decoder designed to operate servos. A servo needs a specific type of electrical driver that produces a variable width square wave control wire with specific pulse timing for servos. A servo is also a three wire device. Two wires are +6volt DC and 0 volt return. The third wire carries the control timed square wave signal. Thus a servo decoder accepts DCC Accessory Commands on its input and outputs the servo specific 3 wire control voltages.

One quite common servo decoder system is made by Megapoints. What you can't do with a servo, is drive it from a pure DC supply like a normal slow action motorised point motor. Yes a servo has a motor but it doesn't operate like a motor does with DC.

Any appropriate servo decoder can be operated by RM & eLink. RM doesn't need to know it is operating a servo, RM is just sending DCC Accessory commands that the servo decoder accepts and converts to appropriate switch left & switch right servo actions.

The Megapoints servo control system has functions to set servo travel limits and configuration actions as part of its own independant operating software. Any other brand of servo decoder will have things that are similar for setting up and configuration.

Hornby do not sell any Accessory Decoder that is compatible with servos.

AFAIK DCC Concepts sell servos with the appropriate decoder built into the servo, I believe they also sell servo decoder boards for use with standard servos like the Tower SG90, but this needs confirming.

[96RAF]

Moderator RogB uses servos with TGG which is similar to RM, so may be able to comment on his controller.

Have a look at the pull down list of controllers in RM when setting up points to see what is already supported.

A quick flag to HRMS will soon tell you if they have anything on the books for servo points.

[St1ngr4y]

@Padders

The DCC protocol for accessory decoders only allows for one of two values to be sent to an accessory DCC address - 0 or 1. So for a set of points they will control left or right, or for a signal, red or green etc. So if you configure your accessory decoder as, for example, a Hornby R8247 decoder, that should be good enough to operate your decoder. On my layout I have a set of level crossing barriers operated by servos and an appropriate decoder. That decoder receives commands 0 or 1 to raise and lower the crossing barriers.

Ray

[Padders]

Thanks all, sounds a bit complex, I think i'll look at GM seep motors as an option to replace Peco.

I have an N gauge layout of Paddington which requires a lot of points to switch between 10 platforms and the GM option seems the most economical with the smaller profile.

Just need to ensure the R8247 can drive them as Peco struggle a bit.

[zeroOneman]

I'm using sg90s & a points decoder I built myself using an Arduino nano. It's not the easiest thing to do, but the results are very pleasing.

https://shedendrly.wordpress.com/points-decoder/

[Barry-350851]

Thanks all, sounds a bit complex, I think i'll look at GM seep motors as an option to replace Peco.

I have an N gauge layout of Paddington which requires a lot of points to switch between 10 platforms and the GM option seems the most economical with the smaller profile.

Just need to ensure the R8247 can drive them as Peco struggle a bit.

 

 

Hi Padders, You could have a read of an earlier thread I made about MP1 point motors

https://uk.hornby.com/community/forum/hm6010-with-mp1-point-motors-354322?ccm_paging_p=1

 

 

They are a servo but operate off standard DC power with their own internal controls.

 

 

I haven't got to buying the Hornby decoder yet, too many other demands on my time, but it is one of my winter projects.

[RB51]

Just seen this. If it’s of any use I use the small sg90 servo motors, from HobbyKing, controlled by a Megapoints controller off, as Rob says, TGG. R-