SPoMoCs (no, it's NOT a joke [or a dirty word!])

[iL Dottore]

Although I am a failry serious person, I do have moments of silliness (such as here: http://www.rmweb.co....arrived-early/) where I came up with idea of SPoMoCs (SelfPoweredMotorisingChipset).

 

Upon reflection, it's not such a silly idea and, I think, one that is achievable with today's consumer electronics technology.

 

If you consider the current DCC setup: Track Power >>> DCC Chip >>> Motor then SPoMoCs would be a variation on this, namely SPoMoC Power Unit >>> Radio Receiver >>> Command Chip (a development of a DCC chip?) >>> Motor.

 

The power unit would be a rechargeable battery (Lithium Ion perhaps?), the radio receiver a derivation of a mobile phone signal receiver (but receiving only), a DCC type chip and a state of the art electric motor (a coreless one, perhaps?). Recharging could be by a pronged cradle (like with the Braun cordless electric toothbrush charger).

 

The setup would certainly fit in a 4mm Loco tender (with the motor in the locomotive), my antique slimline mobile phone is just about the size (height x length not depth) of the new Hornby Castle tender and it has a lot of bits and bobs (colour LCD screen, speaker, keypad, clamshell housing) that would not be needed for a SPoMoC. Stripped down, the entire setup might even fit in a 4mm locomotive boiler - especially if the technology used is a variation/derivation/imitation of that employed in the I-Phone or Blackberry. Based on the available technology today, a SPoMoC would certainly fit in a Class 50 or other diesel.

 

Bump up the battery capacity and you could power a 7mm loco quite easily and with some microelectronics, you may even be able to squeeze the setup into a N gauge 4 car EMU or DMU.

 

The base station (transmitter) could be derived from mobile phone technology

 

Now the difficult questions (for the RMWeb technical experts):

 

• With the current battery, my `phone has a 40 hour standby and 8 hours of continuous (transmitting/receiving) use, of which only a small percentage is with the keyboard illuminated and the LCD screen on. Would this be sufficient to power a locomotive for (say) a 2 hour running session, hauling a reasonable load?
• Could this be assembled using "off the shelf" materials?
• Would anyone know of the approximate cost of the individual components (e.g. motor at ??32 retail) and like to hazard a guess as to cost per complete unit?
• If you could set the specs for the SPoMoC - what would they be?
• If you separate the motor component from the SPoMoC Power Unit, Radio Receiver and Command Chip would this be sufficient to make it backwards compatible?
  
• Any potential drawbacks (technical, technological, mechanical....)?

and finally (and naughtily)

 

• Assuming that a SPoMoC could be brought in at ??50 or less/unit. Would you move to SPoMoCs?

Over to you!:icon_smile:

[Allegheny1600]

Hello or should it be 'Bon journo'!!!!

Thats an intrigueing idea..............

With the rate that mobile phone technology has been and keeps on advancing, i would guess this could be entirely feasable.

One point i would like to make re: recharging.

With todays (let alone tomorrows!) ever finer detailed locos, i would not want to be taking them on & off the track every couple of hours to place on a recharging cradle! How about simply driving the loco to a 'fuelling point' on the layout - which is a section of track where the batteries can be recharged.

This could be a water tower at the end of the platform (in steam days), loco shed, turntable etc or simply a length of track through the station that is powered so the batteries can be recharged 'on the fly'!!!!!!!

Another point is that in todays DCC, i know there are decoders (becoming?) available that can communicate with their base station, exactly why i don't really know as i am a DCC user rather than expert! Therefore, surely your system may require 2 way communication with base, also?

I can't answer any of your technical questions but, unfortunately i can say that if such a system were available, i would not buy it - i simply have too much invested in DCC!

However, for someone converting from plain DC, perhaps....?

Unfortunately if the cost per unit were in the order of ??50 that is a lot of cash to do more or less the same as present day DCC can, at close to ??20 per unit!!!!!

Sorry if i've thrown a dampner on your idea, just giving you my thoughts and YES! I always like new ideas!

Cheers,

John E.

[Adrian Wintle]

It is an interesting concept, but a couple of questions/comments:

 

1. Why limit it to being a reciever? Wouldn't it make more sense to have feedback as well (for programming etc.)?

 

2. The draw for a locomotive in operation is probably a minimum of 10x that of a mobile phone in use and at a higher voltage, so I'd guess that a standard mobile phone battery would last significantly less than an hour if used as the sole source for powering a train.

 

3. You would have to find an open area of the RF spectrum to run this in (more likely the cordless phone/baby monitor spectrum rather than the mobile spectrum) which may affect the size/power consumtion of the system.

 

4. You may find regulatory issues in finding a common frequency to allow production in economic quantities - the same way the model railway manufacturers are having issues with RF wireless throttles in Europe.

 

Adrian

[bertiedog]

It's basically R/C for aircraft transferred to trains and indeed works already in Garden Scales, and there lies the main trouble, the batteries to run the loco......the battery capacity is not enough when brought down to 4mm sizes, it would work, but might not be widely applicable due to the drain on the batteries from the motors on larger models, and smaller ones will not have the space, you are caught out at both extremes.

 

No decoders are needed, R/C channels are enough, but no sophisticated control as such, without using further R/C channels or digital control.

 

It would be feasible to have a standing voltage on the track feeding a re-charge circuit for the power to the batteries, with the R/C controlling the regulator/speed direction etc.

 

There is a side issue of the frequency bands, it is very closely regulated in the UK. Model bands are allocated, and communication bands must not be used for control uses.

 

Stephen.

[ian]

• With the current battery, my `phone has a 40 hour standby and 8 hours of continuous (transmitting/receiving) use, of which only a small percentage is with the keyboard illuminated and the LCD screen on. Would this be sufficient to power a locomotive for (say) a 2 hour running session, hauling a reasonable load?
• Could this be assembled using "off the shelf" materials?
• Would anyone know of the approximate cost of the individual components (e.g. motor at ??32 retail) and like to hazard a guess as to cost per complete unit?
• If you could set the specs for the SPoMoC - what would they be?
• If you separate the motor component from the PoMoC Power Unit, Radio Receiver and Command Chip would this be sufficient to make it backwards compatible?
  
• Any potential drawbacks (technical, technological, mechanical....)?

 

Getting a motor (even a high efficiency one) to do some useful work pulling a train about is a different matter to running an LCD screen.

 

Taking the escap 1628 - which would cope well with the average 'scale' 4mm layout (train set curves, steep grades or 12 coach trains and you'll probably need 2 of them, or a larger motor) - that has a current draw of 250mA.

 

For two hours continuous running that equates to a battery of at least 500mAH. (Don't forget we've got to run the electronics as well.)

 

A typical 11v/550mAH rechargable battery pack would be 6 x 3 x 1.5cm and need to recharge on a suitable charger (connected to a length of track) for about an hour.

 

The reason for sticking to 12V would be for 'backward compatibility' so that you could fit the control unit into an RTR loco without ripping the motor out -subject to current draw, of course.

 

By arranging a constant voltage on sections of plain track (e.g. a DCC controller or straight AC) you could trickle charge the battery whilst the loco is on the layout, only using the battery's charge in electrically dead sections - chiefly pointwork.

 

Linking a Bluetooth chip to a DCC-style decoder would give you your radio control.

 

The system would consist of a Bluetooth device that plugs into your DCC bus (assuming you don't want to re-invent the control system, again backward compatible as your fancy SPoMoC powered model will run alongside your boring old DCC ones). The Bluetooth signal is picked up by the SPoMoC, acted on by the decoder circuitry which then drives the motor using battery power, topped up from the track where available.

 

So, to answer your question iD, yes it can be done with current technology, the electronics bit wouldn't be much more expensive than one of the top end DCC decoders is now, with the added cost of a battery pack (the smaller they get, the more expensive they are) and a quality motor.

 

For those who want to go part way you could just use the bluetooth bit - relying on track pick-up and the existing motor, bluetooth and battery upgrade or bluetooth and motor upgrade.

 

Of course, adding sound will push your current draw up, as will lights, uncouplers, smoke units and steam from the driver's tea mug.

[Adrian Wintle]

The system would consist of a Bluetooth device that plugs into your DCC bus (assuming you don't want to re-invent the control system, again backward compatible as your fancy SPoMoC powered model will run alongside your boring old DCC ones). The Bluetooth signal is picked up by the SPoMoC, acted on by the decoder circuitry which then drives the motor using battery power, topped up from the track where available.

 

The difficulty here is that your standard DCC chip would be expecting a 12-16v square-wave control signal, so you would have to re-design the decoder to run on a DC feed plus a separate control signal (i.e. an integrated reciever/decoder, rather than an add-on reciever). A DCC system would have to be re-designed to know to send some commands over the Bluetooth link rather than onto the track (a fundamental change in the paradigm), although the basic DCC signal could run the charger (and any regular DCC locos).

 

Adrian

[ian]

The difficulty here is that your standard DCC chip would be expecting a 12-16v square-wave control signal, so you would have to re-design the decoder to run on a DC feed plus a separate control signal (i.e. an integrated reciever/decoder, rather than an add-on reciever). A DCC system would have to be re-designed to know to send some commands over the Bluetooth link rather than onto the track (a fundamental change in the paradigm), although the basic DCC signal could run the charger (and any regular DCC locos).

 

Adrian

 

The AC feed would charge the battery and optionally provide the control signal. The DCC decoder circuitry would need to be redesigned on the motor drive, but nothing too complicated. The control signal is a square wave that is converted to +Vcc/0V before it gets to the micro-controller, so for R/C all you would need to do is feed straight to the micro-controller. By providing connections for DCC or Bluetooth input on the controller you can cover both options.

 

A Bluetooth interface would be attached to the track bus. This would pick up the DCC packets and transmit them to the recievers. Again, the circuitry is pretty standard. A clever device could provide RailComm bi-directional signals as well.

 

The Bluetooth loco reciever would be powered from the decoder (in turn either track or battery powered) and pass the DCC signal directly to the decoder (and get one back if RailComm was built in).

 

The Bluetooth datalink is just that, a data link - it uses standard, readily available units to pass data from the device connected to the track bus to the device connected to the loco decoder.

 

Simples

[Dave777]

I'll leave the technical stuff for others, but...

 

Would the market stand a third method of control?

 

and I couldn't see how the power actually gets to the motor - is it via the DCC socket as Ian was talking about here...

 

The system would consist of a Bluetooth device that plugs into your DCC bus (assuming you don't want to re-invent the control system, again backward compatible as your fancy SPoMoC powered model will run alongside your boring old DCC ones). The Bluetooth signal is picked up by the SPoMoC, acted on by the decoder circuitry which then drives the motor using battery power, topped up from the track where available.

 

...in which case all current DCC-ready locos would also be SPoMoCs ready

 

Not sure if you're just talking about having a dabble yourself, but from a commercial point of view the various required bits would need to be fitable as a single unit I would have thought. Also... I'm not clear on what you see as the advantages of this system?

 

 

 

 

 

[The Stationmaster]

There was a chap in the Midlands who had a large 4mm scale layout (in a barn) which used radio control and had the batteries in a vehicle semi-permanently coupled to each loco. I'm not sure how many r/c channels he used but the layout could run several trains at once and the Drivers had to work according to signal aspects as the layouts was also fully signalled - all quite something according to those who saw it.

 

He died some years ago and I don't know what subsequently happened to the railway.

[Dave777]

I vaguely remember that too, I think I saw it (or at least a similar setup) in one of the magazines. The technology at the time meant the batteries (quite chunky, a good 6-7 inches long I seem to recall) had to be kept in the first coach behind the loco which meant it was ideal for passenger services but less for for freight - I seem to remember there were a few goods trains with siphons directly behind the loco!

[ian]

My interpretation (probably completely wrong) is that you could use the radio link (Bluetooth or standard r/c) to get the commands to the loco. The battery would provide power, recharged from powered tracks. By having some plain track powered on a DCC or plain AC bus and leaving points electrically dead you eliminate a lot of the wiring problems.

 

By interfacing to a DCC controller you have the option to add SPoMoCs to an existing layout without converting everything to the new system on day 1, you just wire a SPoMoC interface into the track bus, place a SPoMoC fitted loco on the layout and it would behave just like any other DCC fitted loco.

 

Similarly by making the SPoMoC decoder capable of taking its signal off the track like a conventional DCC decoder you enable a staged upgrade (radio link added later). I'm not sure how useful this would be, but it would be worth considering at the design stage.

 

Advantages? A SPoMoC would be immune to dirty track on a conventional layout and on a SPoMoC only layout would avoid all that nasty live-frog mucking about.

[Dave777]

Ahhh yes, so with no need for the track to provide power that means any compromises on appearance that have to be made from a functional point of view (ie, the need to provide power) are removed and the appearance of the trackwork could improve. You'd still need to switch points, but 'all' it needs to do is provide something for the trains to run over.

 

Okay, I'm seeing that angle at least.

 

 

[34theletterbetweenB&D]

... It would be feasible to have a standing voltage on the track feeding a re-charge circuit for the power to the batteries, ...

This strikes me as key to this development, as it enables the capacity of the battery, and thus its' size and cost, to be much reduced: make all plain track the recharging zone with track voltage at the maximum permitted (24V?) to maximise the rate of recharge, and a very small battery giving only a minute or three of endurance is all that is required. Looking at my rechargeable Dremel which has a motor with the power output required, and operating endurance off the charger base of at least 30 minutes, the components of the device would fit in a typical 4mm tender engine. But they wouldn't fit in a small tank engine / class 08 shunter. Whereas the small battery usually receiving charge set up probably would fit even in very small prototypes.

 

One other thing. Crucial to success of such a concept is something that reliably inhibits operation off the rails (with some kind of defeat available for servicing purposes) to prevent the loco galloping off a workbench, running in a box, etc.

[ian]

Thinking aloud here, with the Bluetooth system - the loco would have to be 'talking' to the DCC interface unit so once that was switched off or out of range the decoder would go to sleep. It would be possible to add a 'lock off' mechanism for storage purposes, perhaps writing a CV that disabled all decoder outputs.

 

For servicing you just need a DCC SPoMoC-enabled system - you don't even need a length of track.

 

As for stopping when it comes off the rails, this is more problematic. The Lenz Power-1 system uses inductance (I think) to detect the presence of the DCC signal even if it is interrupted. This option wouldn't be available if we are adopting the 'don't power the points' philosopy so I suspect you are reliant on pressing the emergency stop button on your handset if you come off the rails.

 

Each SPoMoC, being a Bluetooth device, would have a unique ID. When the DCC interface detects a new SPoMoC within range it would ask if you wanted to add it to the DCC roster. This would mean that you could have two layouts in the same room without any conflict (unless one of the operators was feeling particularly evil...). Once a SPoMoC was paired with a DCC interface it would ignore any other DCC Interfaces unless and until it was out of range, the DCC interface was switched off or the DCC Interface dissolved the pairing.

 

Moving further on, you wouldn't actually need a DCC controller. A PDA or even an iPhone should be able to control a SPoMoC, as long as there was AC power to the track or charge in the battery. Imagine that, you take a loco with you to a friend's layout, put it on the track, pull out your mobile and drive the loco around the layout.

[BrianB]

Funny enough ive been having the same thoughts recently. I'm new to railway modeling, but im a software architect by trade and DCC appealed to me but seemed limited. My thoughts were primarily the use of wireless to expand over and above DCC in a newly architected open format. Imagine finer control, realtime sound from a server, not limited to whats onboard. Telemetry feedback from the train in realtime and with high accuracy, heck even video feeds... micro video cameras anyone. All easy enough within the bandwidth of wireless technology, and to be honest achievable with current chip design architectures based on size. I hadn??™t really considered batteries as being wise based OO scale sizing and battery technology. A better idea would be a Capacitor to allow buffering of power from the rails for moments where track supply dips or in moments where the train is at its limit due to supply. Batteries age??¦ provide not a great deal of benefit to supplying power to rails and add cost.

[PhilEakins]

Has no-one looked at The Red Arrow System which seems to already offer much of what you want out of the box?

 

Phil

[noiseboy72]

Looking into the future, current wireless embedded web-server boards with universal outputs could be shrunk to fit into a loco. This would effectively put a micro PC with the same capability of a current smart phone onto each train. This could report it's position from lineside beacons or even counting sleepers and of course control all the movement, lights and sound. Wireless network control, bandwidth for in-cab video, even communication between trains so that they know how to behave when coupled or run together. Future-proof open architecture with OTA updates of course...

 

Power: How about contactless AC magnetic transmission ? Distances of 5M are now possible, so a few well positioned coils around the layout and away you go.

 

I guess once this technology is adopted for mass market use in Ipods etc, it will be cheap enough for model railways.

 

Anyone say fuzzy logic ???

 

 

[Colin_McLeod]

There is a mobile phone company called ZTC. Perhaps they could develop such a system.