Signal Project

[mrp]

Hello All,

 

I’ve been working on automated signals for my layout.

 

I thought I’d post some pictures of what I’ve got so far in case anyone has some suggestions, or maybe can spot any common configurations that I’ve missed.

 

I’ve based the configurations mainly on what you can see on the Seibu Ikebukuro line.

 

They’re just bare PCBs at the moment and haven’t been painted or anything, so you have to use your imagination a bit.

 

The system uses interchangable heads for the different light combinations that all plug into the same base board.

 

Here’s a picture of a range of heads:

 

 

And here’s a couple of heads next to a Tomix 5564.

 

 

Here’s a video stepping through each aspect for all of the heads.

 

 

And here’s the list of heads I’ve made so far (in the order they’re shown in the video):

 

1. 2 Light - YR

2. 2 Light - GR

3. 3 Light

4. Dual 3 Light, diverge left

5. Dual 3 Light, diverge right

6. 5 Light Type A - YYRYG

7. 5 Light Type B - GYRYG

8. 4 Light Type A - YRGY

9. 4 Light Type B - YRYG

10. 4 Light Type A with Route Indicator

11. Crossing Warning for Track

12. Obstruction Warning

13. Crossing Warning for Roadway

14. Repeating

15. Repeating with Route Indicator

 

So far everything works as planned, but lot's still to do...

 

[kvp]

Interesting. Do you multiplex the signals or each plug has 7 separate channels (+ground)? Also, is there enough room to fit them between two tracks?

[mrp]

Hi kvp,

 

The mast plugs into a small board - currently 35mm x 18mm, although the final should be smaller when I change to 2mm headers and sockets.  For ease, I’m currently prototyping with standard 2.54mm headers, which are about twice as tall and bulky.

 

 

Here’s how the size compares between the 2mm and 2.54mm headers, with a Tomix signal for comparison.  I think the 2mm size will blend into the layout ok.

 

 

I’m planning for the board to fit between two Tomix tracks at regular 37mm spacing like in this photo.

 

You can chain any number of the boards together in any order using a 4-wire cable - +12V, +5V, Data, GND.  A single board has 6 independent LED outputs that go up the mast, although I’m thinking I may knock up a more complex variation for things like double 4-way heads and triple 3-way heads.

 

Also, you can remotely control the individual level of each LED (using 256 PWM steps) which I’ve found you need for matching LED brightness - at default levels the SMD 0805 jade-greens I use seem to be way brighter than other colours - and so I can have different levels for day and night running.

 

Actually, I’m using the same control protocol as Neopixels from Adafruit use.  I'd expect the signals to work with their Arduino library, although I’m not currently using that - I’m using my own PIC code.  For example, here’s one of the signals connected in series on the same bus with a prototype street light that uses two WS2812Bs.

 

 

 

[The Next Station Is...]

Looks fantastic mrp - I love the fact that you've chosen a variety of different signal types to model!

[kvp]

Thanks for the info! 6 outputs means you are using 2 ws2811 chips in each driver board. (and you have 1 unused output pin, that could be used for polarity keying or to be rotationally symmetric) Since the whole system looks like it's actually a pwm based serial protocol that is using shift registers to store data (like an analog rc servo radio protocol), you have to daisy chain the lights and changing the chaining order renumbers each output. This is good since you don't have to set addresses on the boards, but any change on the layout means new id numbers for everything behind the changed point. Very interesting idea. The signal designs are also great and with the right plastic front cover, they would be great for every modeller. Do you plan to sell them? (with or without the driver chips)

 

ps: Actually i'm designing something similar for an L gauge club layout, but with a conventional 2 wire, bidirectional asynchronous serial protocol (12V, D0, D1, gnd) with a tree topology and preprogrammed addresses in each decoder (similar to dcc). Of course for signals only, this would be overkill, but i would like to support throttles, track sensors, control boards and traction drivers (intelligent dual mode boosters) too.

[cteno4]

Kvp,,

 

Just curious if you've looked at the NMRAnet stuff that captain oblivious was doing a lot with in the last few years.

 

Cheers

 

Jeff

[kvp]

Yes, i've read about it, but i was looking for something less complex and easier to implement. The result is a sequencer based strategy, where a sequencer addresses every device for a message. After the address, the device sends out its message. Every other device can listen to it and process it if it wants to.

 

Examples:

-address 1, device is an input board, message contains a switch matrix of 8 switches, turnouts and signals read it and set themselves

-address 2, device is a throttle, message contains speed and direction settings, a traction controller reads and sets its pwm output

-address 3, device is a block occupancy detector; a crossing gate, a turnout decoder and a led display reads it, the crossing gate activates, a turnout sets itself to a route and the led display lights up

-address 4, device is a throttle device, the dcc central reads it and converts it to a dcc message

-address 5, device is a dcc central with a dcc byte, intelligent boosters read and store it (although it's easier to connect them on a separate high speed dcc bus)

 

Essentially it's just a digital crossbar on a tree topology bus. All logic is provided by the elements. Addressing could be done by eeprom programming through messages (like a dcc decoder) or by jumpers (more simple method). No clock signal is provided and the devices use an unary bus. (pull d0 for 0, d1 for 1, pull both for mark) This is a very primitive solution, but easy to implement on almost any device. Addresses are 8 bits, data is 8 bits and the checksums are also 8 bits. With the mark bits, 26-28 bits time is used for each message and a system running at 20 kbits, it's roughly 4 messages per second for every device on a fully utilised bus. A device is little more than an 8 bit pic micro and some output driver chips. The protocol is inspired by some texas instruments equipment from the early '80-ies that used something similar.

 

The led chains used by mrp is a much more elegant and even more simple solution for an output only system, so for easy signal control from a central controller it's way better. You can even add turnout and mechanical signal decoders to the ws2811 outputs. (by providing a dummy load and reading the output by a microcontroller and driving dc motor controllers, you can control up to 6 bipolar /kato or tomix/ turnouts from a single 2 chip signal unit)

[mrp]

Hi kvp,

 

Yes, I went with 2 common pins and rotationally symmetric (so you can plug in the head facing either direction with just a config change).

 

Funny you should mention plastic covers - my first attempt at 3D printed plastic front covers just arrived today from Shapeways.  The resolution of “Black, Strong & Flexible” isn’t up to it, but the more expensive “Frosted Ultra Detail” covers look pretty good - although they’ll need painting.

 

 

One problem with the covers is that they restrict the field of view to basically straight on (which of course is the point of having a hood!).  That’s one of the things I don’t like about the Tomix signals - I'd prefer being able to see the signal aspect from as side-on as possible.

 

For actual layout automation - throttles, sensors, etc - I’ll be using CAN bus (also like you, 4 wires - 12V, CANH, CANL, GND) - and then I’m planning on having a 4-pin signal output on each controller board so I can just hang a chain of signals (and - like you say - lights, crossings, turnouts, etc) from each node.

 

It seems that everywhere you look in Japan you see a level crossing, so I also wanted to be able to add crossings as cheaply and easily as possible.  I've made a prototype crossing board to plug into the signal chain.  It takes six signal masts - with some restrictions on total lights - and with the control circuit hidden under the track.

 

 

Here it is with a couple of heads plugged in:

 

 

The final version will use the 2mm headers so the black bases won't look as outlandish.

 

I guess I must come from the “more blinking lights is better” school…

 

If you're interested, here's my basic signal base board with the two WS2811 drivers:

 

 

[JR 500系]

Oh wow that's cool! Definitely neat! Planning to sell some of them?

[mrp]

Hi JR500,

 

Thanks for the encouraging words.  And thanks also to “The Next Station Is…” from earlier in the thread.

 

Actually, I’ve been thinking that plug-and-play “prototypical” N-gauge signals like this might generate some interest in Japan.

 

Before starting work on this, I looked around to see if there were products I could just buy.  I wasn’t able to find anything even remotely similar other than a few home-brew systems like these:

http://rfc.at.webry.info

http://www.geocities.jp/kame6001/azusa-model/index.htm

And kits like this:

http://www.mes-ekit.com/?pid=58077835

 

I’m a bit surprised that there’s nothing out there.  I much prefer the look of layouts with working signals everywhere.

Edited September 22, 2014 by mrp

[E6系]

Hello Mr mrp,

 

I am very interested in your signals.  Have you considered making them compatible with the Digitrax signal bases?  Then we could purchase your masts and replace the Digitrax ones.

 

As the Kato DCC equipment is manufactured by Digitrax, some vendors in Japan are selling Digitrax products.

[mrp]

Hi E6系,

 

To be compatible with the SMBK it looks like all you need are the mast PCBs themselves with a few current limiting resistors added and changing to a 10-pin connector (and re-laying the traces to go to the correct pins, of course!).  That would be easy enough to make, although it wouldn’t be “compatible” with my base.

 

From the SEC8 documentation it looks like the brightness of each LED can’t be individually controlled, so I guess you’d need to select appropriate current limiting resistors to get matching output levels from each type of LED.  For example, the jade-green SMD LEDs are a lot brighter than the other colours.

 

Also, I don’t think the way I do Repeating signals would work, since they currently need a +12V common anode to drive 3 LEDs in series, and it looks like the SE8C just supplies 5V.

 

It would be interesting to make some masts to try out, but I’m not sure where we’d start.  For example, I don’t have easy access to any Digitrax equipment.

[E6系]

Hello Mr mrp.

 

My base board is 20mm thick.  If I use your signal base board I must surface mount on top of my boards.  Digitrax solves this by setting the circuit board vertically.  Digitrax includes the necessary resistors on the mast bases.  I am very interested in what you are doing.  Finding an easy way to connect to Digitrax system would be of interest to me.

[cteno4]

mrp,

 

Wonderful work! You may have a great product to eventually sell!! Kudos!

 

Cheers,

 

Jeff

[mrp]

Hi E6系,

 

If you want to continue using the Digitrax Signal Decoder and ribbon cable, then I think the easiest way to do it would be just to make a new set of mast boards the same height and dimensions as the SMBK but with different shaped heads.

 

For example - for the 4 light and dual 3-light - something like this:

 

 

Maybe I can get some sample PCBs manufactured using this design and you could test them?

 

I think it would be best to test one or two designs first and confirm that the dimensions are correct, that the LEDs are wired correctly, and that the masts work in both the A and B/C orientations.  From reading the manual I think I understand how the SMBK works, but I don’t have any way to test here.

 

[Melandir]

Hi mrp

 

I'm interested too in your signal system, please keep us updated on your system develop and if you ever plan to sell it

[macdon]

I guess I'll join the rest of the guys here - color me interested if ever you decide to offer.

 

Your last link above re level crossing kit - loved it!  I dont know if he offers a completed kit as I dont know anything about electronics. I know kato sells one but just a bit out of my reach.

 

Thanks for sharing your vid - great job!

 

Mardon

[Kabutoni]

Same here! I'm very interested! If this could be made as a plug-and-play for DC operated layouts, this would create a huge interest in Japan. DCC is hardly used here, so DC is the way to go.

 

A good marketing strategy would be to come up with a simpleand affordable modular circuit that can be used on any single direction loop and make it expandable to a bi-directional layout. That is, if that would be possible.

[kvp]

 

If this could be made as a plug-and-play for DC operated layouts, this would create a huge interest in Japan. DCC is hardly used here, so DC is the way to go.

Afaik mrp's system isn't DCC based, so you can use any kind of control system (analog or digital) for the trains. Also, i think it's possible to add analog PWM traction controllers to the end of the CAN bus too, instead of a DCC booster. There is no automation in the signalling protocol itself, so you have to throw switches or something similar (like use a touchscreen) to get different signals. This can be connected to the turnout control logic like in the Digitrax system, or into an automatic block protetction system (like the old BTTB systems did) but that is a rather huge piece of automation.

 

Maybe mrp could tell us more about the actual control system that drives the signals, so users don't have to flick a switch back and forth to get blinking lights on the crossing gates. I'm 100% sure he has a working digital control and input system, since the lights work perfectly on the demo videos. I would also like to know if this control system does or will support Tomix TCS sensor inputs for automation?

[mrp]

Hi All,

 

Thanks again for all the comments.

 

It looks like I might have let the cat out of the bag a bit early - maybe I should have built something that actually works first!!!

 

I guess the stuff I’m working on is intended more for DC layouts - part of my larger DC block control plan - since I’m 100% a Tomix addict, so DCC isn’t much of an option.

 

Currently I’m planning on using iTrain for my layout automation.  I find it quite well designed and easy to use.

 

Actually, I just got my prototype iTrain interface board up and running today.

 

Here’s a short video of iTrain controlling the signals - I’m reserving a route by dragging and dropping the loco icon on the destination block and then faking the locomotive running by clicking through the occupancy detectors.

 

 

I decided to use the Dinamo/PM32 protocol between iTrain (running on a Mac) and the controller board because it’s fairly well supported, and already has a block throttle command for DC automation.

 

Here’s the prototype controller board wired up:

 

 

There’s a lot of extra cables connected for debugging/programming including a serial debugging console and the PIC programmer - the final setup would just have the FTDI usb connection to the PC.  Please excuse the board layout, etc - it’s not really intended for publication!

 

I've also prototyped a board for Tomix TCS sensor input and Tomix turnout control - I even found the correct TCS-compatible sockets and plugs (Molex 1.25mm PicoBlade) - but I’m still thinking over how best to integrate all these pieces.

 

It sounds like there might be some interest in a much more light-weight control system - maybe something that can take a dozen or so sensor inputs and control a bunch of turnouts, signals and other accessories.  The problem I think is that you’d soon wanted automated PWM throttles - then your talking about setting up blocks - and by now you might as well do it on a PC.

 

[Kabutoni]

Mac software, USB and Tomix TCS? You have my full attention! :D

[mrp]

Hi Toni,

 

I should tell you what I’d REALLY like to do.

 

In the bottom of Tomix FineTrack are rows of square holes that expose the track:

 

 

The distance from the bottom of the track-bed to the bottom of the rails is about 4.8mm.

 

I’ve been trying to source SMT spring-loaded pogo pins that I could mount on a thin PCB, so that when a piece of track is clipped on, the pins would make the electrical connection to the track.

 

I think I’ve found something (on AliBaba) that just might work, so I’ve ordered a few samples.

 

 

If it works, I can imagine a range of boards that would simply clip onto a piece of FineTrack for signals, turnout control, throttle connections, etc…

 

And no wires!!!!

 

Oh well - I guess I can dream…

 

[E6系]

Hello Mr mrp,

 

Would you have a link to that AliBaba product? I am wondering if it would make a good connector between base boards?

[mrp]

Hi E6系,

 

Yes, of course.  Here is the link:

 

http://www.alibaba.com/product-detail/2-0-5-2MM-spring-pin_950227261.html

 

I guess this company isn’t the manufacturer - only a reseller - but they were the only company I could find on AliBaba that had the 5mm SMT pogo pin available.

 

I would have prefered to purchase through AliExpress - since the suppliers there generally have smaller mimumum order quantities and lower shipping costs - but I couldn’t find this exact size.

 

For example - for a different application - I recently purchased 100 pieces of these 16mm pins for $6.58 and they arrived quickly and without any problem:

 

http://www.aliexpress.com/item/FREE-SHIPPING-100PCS-LOT-P75-B1-15-85mm-Two-Part-Spring-Test-Probe-Pogo-Pin/1857433056.html

 

What do you mean by “a good connector between base boards”?  Can you show a picture or diagram of what you're trying to connect?

Edited September 27, 2014 by mrp

[E6系]

Hello Mr mrp,

 

Very interesting product.  I am concerned that the spring pin Pogo pin does not have enough surface area in contact with the underside of the rail.

 

Regarding base boards, my base boards all join together with Hafele Maxifix connectors.  These are very good.  Each side of each board is equipped with two of these quarter-turn connectors.  A pin goes between them.  A quarter turn with an Allen key locks everything in to place.  I have 40mm diameter dowels and holes for locating precisely.  It is so accurate that I do not use rail joiners between boards.

 

Here is Hafele Maxifix: http://www.hafele.com/us/products/maxifix-connector-bolt-hafele.asp

 

I use motorcycle connectors such as these to connect the wiring between adjoining boards: http://www.ebay.com/itm/9-Way-Electrical-Connector-2-8mm-ALL-TYPES-AVAILABLE-/180363998491?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item29fe88351b

 

The wiring loops through vacant 40mm holes in the boards.

 

Currently, I use different colours to distinguish between trunk DCC power, block power, accessory power, and earth.

 

I am thinking that spring pin Pogo pin could be screwed through the side, mating with similar on the next board.  I might need a row of 30 or so on each connecting side of the board.  Then, when I lock two boards together I won't need the motorcycle plugs.

 

So sorry, no photo on hand.  Will try to arrange.