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An Equivalent to the Hornby Sapphire For N-gauge


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  • RMweb Gold

As the topic suggests really, Is there a decoder like the Hornby Sapphire that can be programmed with simple automatic running, but small enough to fit in N-gauge Locos?

 

I have asked Hornby as initially they did say they would be launching a Mini Sapphire, but that went by the wayside and it's not going to happen.

I only need it to run forwards for a few seconds then stop then go backwards so nothing too complicated.

I don't really want to use a standalone system such as the NCE mini panel as the micro layout is almost complete and threading wires from one end to the other will be a nightmare.

 

So is there another decoder out there that can do this?

 

Cheers

 

Ian

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Lenz Silver Mini, but only if you install an ABC braking zone at each end of the layout (5 or 6 diodes to make each ABC brake module, so cost is about £1). Then setup the "auto shuttle" feature in the Silver decoder. (The Gold does it as well, but only worth fitting if you've also space for a Power-1 module).

 

- Nigel

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Ian

A fast response rectifier diode. Current handling of 1amp is more than enough for N.

 

Standard 1N4001 might work, but can be a bit slow for ideal.

 

Diagram on this page, to disable the autostop fit an on/off switch over the rail break. Note that the break at each end is on opposite rail.

http://nigelcliffe.blogspot.co.uk/2009/06/abc-stoppingslowing.html?m=1

 

Nigel

 

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Ian

Here's my version of the Lenz BM1 5 diode module built in various sizes on veroboard...

http://www.rmweb.co.uk/community/index.php?/gallery/image/24940-assymetric-dcc-generator/

Diode spec is not too critical but you need to smartly drop around 2v across each diode to make detection by the loco decoder reliable.

Just follow Lenz ADCC rules for rail breaks (download BM1 info), etc and use any smart loco decoder - Sapphire, Lenz Silver/Gold.

Lenz allows a slow/stop to be made on defined distance whereas Hornby stop is less accurate being time based.

Rob

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Lenz allows a slow/stop to be made on defined distance whereas Hornby stop is less accurate being time based.

 

As I said in my blog article, referenced above, the Lenz constant distance stopping behaviour is badly implemented.

Zimo have done constant distance properly.

ESU might have done it properly, their manuals suggest it is, but I've not tested it yet.

 

- Nigel

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  • RMweb Gold

Hi Nigel,

 

Well I bought two BM1's as it was quicker and easier to just nip up to Digitrains and get them for a trial.....yes only 2 just to test at one length of the straight.

Also got the Lenz Silver mini+ to test with.

 

It works OK as long as it's only the one loco!

I have a two car DMU with the light bar and directional lighting in the non powered coach which is trailing the powered loco into the stopping section this seems to cause problems with erratic braking distance.

Whats the easiest way to overcome this besides using just a single car DMU :mosking:

 

I have a Zimo MX621N so could try that to see if it works any better.

 

Reading the instructions it looks like it may have to be a BM2 to give a braking zone but not too sure.

 

Cheers

 

Ian

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Ian,

 

The BM2 is not relevant. It's also expensive.

 

For the 2-car unit, the lighting unit is bridging the brake zone causing it to reset, so the stopping distance will be when the lighting car fully enters the brake zone. If the lighting car is picking up intermittantly, then the effects will be variable.

 

I can think of a few ways round this (apart from removing the lighting unit!). You could wire the two cars together at the pickups, so the combined unit now has eight axle pickup (or disconnect the light unit from its pickups, and wire it back to the power car, giving four axle pickup). That should make things more predictable. Alternatively, there are ways of switching brake modules when fully inside them, but it will require DIY electronics assembly; there are some notes in the files area of the Yahoo Zimo group.

 

There may be some notes on ABC braking in either Zimo or Lenz manuals to deal with trains not fully inside the section, or with trains where the power car is pushing the train (effectively what you have with a two-car DMU).

 

 

A Zimo decoder won't help. Whilst a Zimo stops better under constant braking distance, it does not include the auto-shuttle capability. Only the Lenz has implemented that detail.

 

 

 

A totally different approach would be to use a PowerCab as the controller, and add the "MiniPanel" to the PowerCab. Wire a track detector into the track at each end of the run, and connect to the MiniPanel. Setup the MiniPanel to reverse the loco. It might need a few tricks to get a "wait" at the station as well, but should be possible. Simplest detector would be a reed switch buried in the track and magnet glued under the DMU.

 

 

 

- Nigel

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  • RMweb Gold

Thanks Nigel!

 

As I suspected.

I did actually try this out last night, I removed the light unit and turned the direction lighting off using the switch on the bottom of the loco, everything worked fine then.

The problem would be when it reverses back and gets to the other end!

 

It looks like the pick-ups for the unpowered unit are at the far end(need to check this first) which as you say means the full two car length needs to be in the braking zone.

I might be able to move/add the pick-ups to the front bogie (or middle) where the two units couple up.

This way the first powered unit and the first bogie of the unpowered unit will all be in the brake zone almost at the same time, which "should" give enough breaking time and distance.

 

The constraint I have is that it's a box file layout, and the box file is on it's side which only gives me a short braking zone.

It's actually quite good as I've used the join between the box files to create the rail gap for the braking zone, I've actually got the loco to stop just less than 5mm from the end of the box file wait for a few seconds then return back to the other end, which needs adding and finishing.

 

post-6745-0-11210100-1338108502.jpg

 

post-6745-0-25314200-1338108500.jpg

 

This is one of the reasons I didn't want to use the mini panel as there would be cables everywhere linking each end together outside of the box files.

I should have thought about this earlier as I could have run extra wires in the through the tops of the viaduct arches.

 

Thanks for the info I will keep on trying.

 

Cheers

 

Ian

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  • RMweb Gold

A quick video showing everything in operation, as can be seen I have taken off the second unit!

 

http://youtu.be/5bdcuIsI5eE

 

This shows the back of the layout and how the loco will creep to a stop to make sure it reaches the constant stopping distance set.

I've set a stopping delay of 1second for this test.

Sorry for the quality of this one I had to compress the video by quite a lot to upload it, although the above one was just uploaded, took a while though!

 

http://youtu.be/BMmXKF1R_c0

 

Just need to get the second track down and have two running backwards and forwards!

 

Cheers

 

Ian

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  • RMweb Gold

Hi Mike, the last creep movement is only when its a single DMU, when I have both together to get the braking distances working correctly I have to have almost no braking distance, so it's a virtual dead stop.

 

Thanks again Nigel for the advice and help!

Works a treat.

 

In the end I just connected the two car DMU together, soldered some TCS decoder wire (32gauge very thin) to the solder pads on the decoder socket in each unit then ran the wires to the coupling up point.

As it's close coupled just removed the perspex glass from the doors and threaded the wire through these.

In case I need to uncouple them I have used some Sound traxx mini connectors:-

 

post-6745-0-15925700-1338641658_thumb.jpg

 

post-6745-0-61177700-1338641673_thumb.jpg

 

I have just pushed these back in to the units two on each side, they are a really tight fit so takes some force to push the pin in!

 

Once the CV's have been programmed this does work, although it does take some fine tuning with the speed control to keep everything it sync!

 

post-6745-0-13280800-1338641948_thumb.jpg

 

And finally everything running in automatic, and yes I know these two would never have run together, but in my world they did xD

 

http://youtu.be/8NcD-uoaWaA

 

Thanks again for all the help and advice!

 

Cheers

 

Ian

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