Is it possible to control points with function buttons?

[JSModels]

I have a query which at first seems simple, but not knowing much about these things the more I think about it the more complicated it gets...

 

The Problem:

 

I have a small shunting layout, with only 2 points. This layout will only ever have one loco on it at a time. My DCC controller is a Roco 'Power Mouse 2' (LokMaus 2) and at the moment, the points are controlled by slide switches with rigid links to the tiebars. Both can be seen here:

 

 

The loco is very basic, with none of the DCC functions in use.

 

I have a loco which is very reliable, as is the automatic uncoupling, so the layout is very 'hands-off', but reaching to the front edge of the layout to change the points seems incongruous and, for me at least, ruins the illusion. So my question is this:

 

Is it possible to control two point motors using two of the function buttons on the controller, without having to change the controller address?

 

If so that would make the layout completely hands-off, with everything controlled very simply via the handset. I'd be very happy with that, but I have no idea how to actually achieve it! Being a shunting layout, it would be far too much hassle to have to change addresses every time you wanted to change a point, then change it back to move the loco, then change to the other point address, etc....

 

My first thought would be to use DCC Concepts Cobalt IP Digital point motors, with both set to the same DCC address, but I don't know if it's possible to program them to respond to different function buttons? I don't even know how these would normally be operated, the instructions on their website just says "Use your DCC system's instructions for changing a turnout"! I have the instruction manual for the controller, but point control isn't mentioned.

 

Alternatively, I guess I could use an additional chip, with the same address as the loco, to duplicate the function switching, but I've no idea how to then use that signal to operate a point motor. I don't even know if the function buttons on this very basic controller are momentary or toggle on/off.

 

Other than my idea to use the Cobalt point motors, I have no preference at the moment as to what type of point motor to use. I'd be open to using any type that would allow me to control them via the function switches!

 

I don't want the solution to be overly complicated, or costly - the cost of 2x cobalt point motors (£50) is definitely the upper limit of what I can spend on this!

 

Any obvious solutions out there?

 

Thanks in advance, any guidance/ideas would be gratefully received!

 

 

JRB

[Crosland]

Theoretically it's possible.

 

Addresses for loco decoders and accessory decoders are in different "address spaces" so loco address 3 is totally different to accessory address 3. An accessory decoder set to the same address as a loco would ignore any function control packets.

 

What you would need is a loco decoder that can drive point motors, set to the same address as the loco.

 

It should be possible with low current stall motors and a few extra components.

 

Some decoders (e.g. some Zimo) can drive servos, so you could set one up to control points using servos. I don't know if they have more than one servo output, however. Nor do i know how the servo output is controlled from functions. More research needed.

 

Solenoids would need even more hardware but still possible.

 

How are your electronics skills

 

[John ks]

As far as I know accessory decoders can't be controlled by function buttons ( some one will correct me if I'm wrong)

What could work will require a mobile decoder set to the same address as the loco

connect  a relay to the function output wire 

the relay will need to be low current so it doesn't  overload the decoder & you should use a snubber diode across the relay to prevent the back EMF from destroying the decoder

Wire the relay contacts (from a 12V DC supply) to reverse the polarity to the point motor(Tortoise or similar)

 

Provider your loco doesn't have headlights you could use function 0 (headlights) but you would need to remap this function to 2 buttons & make them non directional

Or you could use functions 1 & 2 without the need to remap (not sure if your DCC toggles F2 on & off or is set up to be on only while the function button is pressed(like a horn/whistle))

 

John

Edit while I was typing this Crosland posted his reply

Edited January 12, 2020 by John ks

[JSModels]

Thanks to both of you for your replies.

 

I was thinking of a loco decoder, rather than an accessory decoder, so at least I was on the right lines!

 

I've done some further research, and I now *think* that the Cobalt IP Digital point motors can be programmed to use function buttons. I've e-mailed DCC Concepts to confirm a) if that's correct, and b) if 2 point motors can use the same address, but different function buttons. If that's the case, then that would seem to be the simplest solution. If not, I'll have to go down the route of a decoder and relays as per john ks's post, and take it from there.

 

 

JRB

[JSModels]

I've now had clarification from DCC Concepts that this will NOT work. They've said that the IP Digital point motors will only respond to accessory addresses, and will not respond to loco addresses.

 

So now I think the plan is to use a 2nd loco decoder (essentially duplicating the one in the loco) and use each of the 2 function outputs to control a small relay. I can then use the output switch of the relay in place of the push buttons shown here:

 

 

If the function buttons are set up as momentary, then it can be wired as a single normally open relay, wired between pins 7 & 9 (as per the centre one in the above image). If the buttons are latching, then I can wire the contacts as a changeover switch using pins 7, 8 & 9 as per the bottom one.

 

Nowhere seems to have stock of the digital IP point motors at the moment (including DCC Supplies themselves) but in the meantime I need to work out the details of how to correctly wire some micro relays to a decoder without blowing it up!

 

JRB

[JSModels]

I think I've got this sorted in my head now!

 

I've discovered that the function keys on the LokMaus are latching, i.e. press once and it switches ON, press a second time to switch OFF.

 

I can use a Zimo MX617 chip, and wire it as follows:

 

 

This should do the trick, I think? Only 1 shown, but can be duplicated on other output(s) for up to 4 points. Each output is rated 0.8A continuous, so shouldn't have any issue driving a sub-micro relay (one like THIS only draws around 12mA)

 

A couple more questions, if I may? What voltage relay should I use? I really have no idea what the voltage will be on the positive pin of the chip, will it be 12V? Or will it be the DCC rail voltage at around 15-16V? Also, what type of diode should I use for snubbing the back EMF? Would 1N4005 be ok?

 

Is there any disadvantage to using an MX617 or similar chip & not connecting anything across the motor output? Would I be better using an MX681 function-only chip?

 

PS - I looked into the Zimo function chips that can be used to control servos - it looks far more complicated than I'm capable of dealing with!!!

 

I think I'm going to look at other point motor options rather than the Cobalts; other than the price, they're also quite large, and may be too big to fit within the depth of the baseboard. If I can find some other, lower-profile slow-action point motors then that would be great.

 

 

JRB

[Dungrange]

46 minutes ago, jrb said:

I think I'm going to look at other point motor options rather than the Cobalts; other than the price, they're also quite large, and may be too big to fit within the depth of the baseboard. If I can find some other, lower-profile slow-action point motors then that would be great.

 

Most of our club layouts use Fulgerex point motors, which are lower profile than the Cobalts.  

 

http://fulgurex.ch/en/index.html - I can't seem to link to the accessories page directly.

 

I'm not sure about UK suppliers, but DCC Supplies have them listed, albeit out of stock, but they are no cheaper than the Cobalt. - https://www.dccsupplies.com/item-p-100284/fulgurex-single-point-motor

 

As for your other questions - I can't comment.

[John ks]

JRB said

A couple more questions,

What voltage relay should I use? I would use 12V relay

I really have no idea what the voltage will be on the positive pin of the chip, will it be 12V?  Should be about 1V to 2V lower than Rail voltage

Or will it be the DCC rail voltage at around 15-16V? As above

Also, what type of diode should I use for snubbing the back EMF? Would 1N4005 be ok? Yes

 

Is there any disadvantage to using an MX617 or similar chip & not connecting anything across the motor output? No except you may need to program on the main or temporarily connect a load across the motor terminals to get feed back from the decoder

Would I be better using an MX681 function-only chip? Only advantage I could see is if the MX682 MX681 is the cheaper option

 

You can use a split PS (power supply) ( (+)12V, 0V, (-)12v) or use a relay with DPDP contacts & a normal PS ie 12V (+) & (-)

 

 

John

 

 

 

Edited January 12, 2020 by John ks
mistake

[Crosland]

Just to emphasize, the Cobalt IP is an unnecessary addition. John KS shows a better solution.

 

[WIMorrison]

These motors are even better

 

https://www.dcctrainautomation.co.uk/mp1-point-switch.html

 

i have 16 of them now, will be using them for everything going forward

[JSModels]

2 hours ago, Crosland said:

Just to emphasize, the Cobalt IP is an unnecessary addition. John KS shows a better solution.

 

 

I agree, thanks for your input on this.

 

2 hours ago, WIMorrison said:

These motors are even better

 

https://www.dcctrainautomation.co.uk/mp1-point-switch.html

 

i have 16 of them now, will be using them for everything going forward

 

They look perfect! Never seen them before. I'll get a couple of those ordered (they're OOS at the moment).

 

JRB

[newbryford]

 

 

On 12/01/2020 at 17:28, jrb said:

I've now had clarification from DCC Concepts that this will NOT work. They've said that the IP Digital point motors will only respond to accessory addresses, and will not respond to loco addresses.

 

So now I think the plan is to use a 2nd loco decoder (essentially duplicating the one in the loco) and use each of the 2 function outputs to control a small relay. I can then use the output switch of the relay in place of the push buttons shown here:

 

 

If the function buttons are set up as momentary, then it can be wired as a single normally open relay, wired between pins 7 & 9 (as per the centre one in the above image). If the buttons are latching, then I can wire the contacts as a changeover switch using pins 7, 8 & 9 as per the bottom one.

 

Nowhere seems to have stock of the digital IP point motors at the moment (including DCC Supplies themselves) but in the meantime I need to work out the details of how to correctly wire some micro relays to a decoder without blowing it up!

 

JRB

 

The Lokmaus instructions are quite clear that it can only control accessories that will accept loco addresses - hence your issues.

 

A changeover relay won't work on 7/8/9 as the contact change is too fast for the Digital IP to see. It needs a split second or so to see a break before make - but longer than a relay will take.

 

DCC Supplies don't normally stock DCC Concepts Cobalts...............

 

They sent out a newsletter in the past few days - they are back in stock this week/early next week depending on customs clearance.

 

 

 

[JSModels]

15 hours ago, newbryford said:

The Lokmaus instructions are quite clear that it can only control accessories that will accept loco addresses - hence your issues.

 

A changeover relay won't work on 7/8/9 as the contact change is too fast for the Digital IP to see. It needs a split second or so to see a break before make - but longer than a relay will take.

 

DCC Supplies don't normally stock DCC Concepts Cobalts...............

 

They sent out a newsletter in the past few days - they are back in stock this week/early next week depending on customs clearance.

 

Thanks, I did of course mean DCC Concepts, not DCC Supplies.

 

Anyway as Crosland pointed out the Cobalt IP is not needed as I'm now going down the road of using a function decoder, and will connect that via a relay to the point motors suggested by WIMorrison.

[JSModels]

Thanks to all who helped and/or offered advice on this one - I think I've got it sorted now. Most of the bits have arrived:

 

 

The MP1 point motors are brilliant little things (even tinier than I expected!). Just a few more components still to come, then I've got the board to make up:

 

 

The two point motors will be controlled by F1 and F4, due to the way the buttons are laid out on the controller. F2 will switch the building lights on & off (hence the 3V input as well as 12V), and F3 will be spare, with the relay contacts carried to 3-way headers for future connection via servo connectors. The coloured rings indicate where the funtion wires will be soldered (for some reason, FO3 and FO4 don't seem to have an assigned colour, so I've just used purple & yellow).

 

I'm 99% confident that I've not missed anything or made any schoolboy errors with the veroboard layout, but that's usually at the point where someone else points out a glaring mistake!!! (if you do spot one, please let me know)

 

 

JRB

 

PS - I don't think I mentioned it previously, but I did find confirmation that on the LocoMaus the function buttons toggle on and off, and are not momentary (otherwise the above wouldn't work!)

Edited January 19, 2020 by jrb
Put CORRECT wiring diagram in!

[sir douglas]

i dont know the details but yes, our club has DCC layouts that have point control done through the hand held , one of which is Burnroyd works which will be at Pontefract show next weekend

[JSModels]

18 minutes ago, sir douglas said:

i dont know the details but yes, our club has DCC layouts that have point control done through the hand held , one of which is Burnroyd works which will be at Pontefract show next weekend

 

I'm guessing that's done as accessories with a more complex handset; this is to use functions on a basic handset.

 

JRB

[JimFin]

Appreciate the question has been answered and progressed but here is an alternative solution.

 

Use a 4 function decoder with the function outputs set to pulse. Use an ESU Servo Pilot controller but essentially in analogue mode. Only provide a power supply to the power socket, no input to the track socket. Wire the common + to the manual inputs, F1 and F2 to the directional pins for point 1 and F3 and F4 for point 2. Connect the servos and program using the Servo Pilot buttons (per instructions) for start, end, and speed control. 

 

It would have capacity for a further 2 servos, either for points, semaphore signals or other moving accessories if you upgraded to an 8 function chip and you could still make use of the directional light capability and of course connect the motor function to the Meccanno motor and gearbox under the turntable, that's not a joke either, it works on my layout!

[JSModels]

By way of an update/conclusion, I have now succeded in acheiving what I was looking to do. Rather than duplicate content, I've posted the update in my layout thread here:

 

 

JRB