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Brainstorm on going digital

Postby JoostV » Fri Nov 29, 2013 9:43 am

Hi all,

Coming from the scale HO having DCC decoders in the locomotives I was wondering if I could somehow go digital on t-gauge.

As there's no space at all I was thinking following:

- Breakdown the track in blocks
- Create the digital bus (2 wires) which in H0 connects the controller to the track
- Put a DCC train decoder between the digital bus and the track (one decoder for each block)
- Limit output of the train decoders to 4.5v

This in theory would allow me to set the speed on each block independently by selecting the decoder address and turn the knob on the controller

Does above theory make any sense. Any obvious pitfall's?
Cheers,
Joost
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Re: Brainstorm on going digital

Postby JoostV » Fri Nov 29, 2013 2:36 pm

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Re: Brainstorm on going digital

Postby PolarExcess » Fri Dec 20, 2013 3:03 am

JoostV,

One idea might be to replace the decoder wires with the smallest possible gauge, perhaps kynar. Then install the decoder in the non motorized car directly behind the motorized locomotive and place a flexible diaphragm between the two cars to hide the wires. Refer to attached picture.

Others feel free to chime in and keep this brain storm going.

1.png
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Re: Brainstorm on going digital

Postby Slarge » Fri Dec 20, 2013 9:55 am

If you ran "trains" rather than locos (as per the larger scales) I see no problem with the above idea.
If you think about the concept of multiple units as used so far this makes perfect sense. Take the extended HST for example, There are 3 powered units, now I don't know much about DCC I will admit, I presume the decoder would need to be linked to each motor, so taking the above idea there would need to be a wired connection from one end of the train to the other, I would want some kind of micro pin connector to allow the train to be broken down and stored, this connection could also be used for "close coupling" (but what about freight wagons?).
The decoder could be in any of the 6 unpowered cars but the wires would need to pass the central motor at some point. (that leaves 5 empty cars, go crazy, add sound!).
Intresting concept, I look forward to more musings/thoughts.
Shame you can't yet "print" your own decoder, the science/tech isn't that far off the horizon (light years away in consumer terms though).
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Re: Brainstorm on going digital

Postby JoostV » Fri Dec 20, 2013 11:42 am

And how about my initial idea to put the decoder on the track, thus creating block's (like analog block system)?
Cheers,
Joost
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Re: Brainstorm on going digital

Postby PolarExcess » Fri Dec 20, 2013 8:46 pm

Slarge & JoostV,

I have some addt'l thoughts. More later, probably this wkend.






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Re: Brainstorm on going digital

Postby nscaler69 » Sun Dec 22, 2013 1:29 pm

JoostV wrote:And how about my initial idea to put the decoder on the track, thus creating block's (like analog block system)?
Cheers,
Joost

You mean something like using this; http://www.ontracks.co.uk/index.php?page=product&prodID=165499 interestingly this Busch HOf stuff uses 3 volt power and locos has magnetic wheels.
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Re: Brainstorm on going digital

Postby PolarExcess » Sun Dec 22, 2013 11:58 pm

Correct, a decoder would have to be connected to each motor. Though, it is possible to connect a single decoder to 2 motors.

If you ran a T-Gauge steam locomotive, the decoder might fit in the trailing tender.

Slarge, you raise several valid concerns, such as the micro pin connector, etc. My first step would to attempt decoder implementation on the simplest possible scale, such as using only two cars, a motored locomotive and an hollow passenger car to store the decoder. If a proof of concept was achieved, then I'd tackle the multiple unit wiring issues. Sound would be icing on the cake.

One thing to keep in mind is that DCC operates on constant voltage and it is the decoder that instructs the motor on how fast to turn, based upon your command. Therefore transition to a DCC track prevents simultaneous operation of DC (conventional) locomotives, unless they run at full speed.

Input track voltage might be another obstacle. Does the track transformer have enough current to power the decoder? Does the decoder accept AC/DC current or both?

I'm interested in reading additional input on this interesting topic.


Slarge wrote:If you ran "trains" rather than locos (as per the larger scales) I see no problem with the above idea.
If you think about the concept of multiple units as used so far this makes perfect sense. Take the extended HST for example, There are 3 powered units, now I don't know much about DCC I will admit, I presume the decoder would need to be linked to each motor, so taking the above idea there would need to be a wired connection from one end of the train to the other, I would want some kind of micro pin connector to allow the train to be broken down and stored, this connection could also be used for "close coupling" (but what about freight wagons?).
The decoder could be in any of the 6 unpowered cars but the wires would need to pass the central motor at some point. (that leaves 5 empty cars, go crazy, add sound!).
Intresting concept, I look forward to more musings/thoughts.
Shame you can't yet "print" your own decoder, the science/tech isn't that far off the horizon (light years away in consumer terms though).
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Re: Brainstorm on going digital

Postby PolarExcess » Mon Dec 23, 2013 12:05 am

With this block method, could you run multiple independent units on the same track?

What would this block method offer over tradition T-Gauge transformer control?

I like the brainstorming. Thanks for starting it.

JoostV wrote:Hi all,

Coming from the scale HO having DCC decoders in the locomotives I was wondering if I could somehow go digital on t-gauge.

As there's no space at all I was thinking following:

- Breakdown the track in blocks
- Create the digital bus (2 wires) which in H0 connects the controller to the track
- Put a DCC train decoder between the digital bus and the track (one decoder for each block)
- Limit output of the train decoders to 4.5v

This in theory would allow me to set the speed on each block independently by selecting the decoder address and turn the knob on the controller

Does above theory make any sense. Any obvious pitfall's?
Cheers,
Joost
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Re: Brainstorm on going digital

Postby dkightley » Mon Dec 23, 2013 1:41 am

With this block method, could you run multiple independent units on the same track?
No.
What would this block method offer over tradition T-Gauge transformer control?
In train control terms it would depend on the size of the layout. With only two or three "blocks", it would be cheaper to use one of the existing PWM controllers for each section of track....but once you get above a certain number of blocks, the cost of a single digital unit and a number of decoders will be less.

One basic obstacle to bear in mind, though...is what happens when a powered unit crosses the join between one block and the next? With one axle connected to block A and the rest connected to block B, there would be a direct short between decoder outputs through the internal power connection in the unit. Would this cause havoc to the decoder circuitry? And what about where the second block is set to run in the opposite direction? The least likely thing would be a train oscillating furiously back and forth over the gap!

Robins Run has two separate loops powered by separate controllers. There are two cross-over sections, each of which can be connected to either loop....so accidental shorting of the controllers is reduced to a low risk....but not prevented. Where you deliberately run from one block to the next block under power is a different thing!!

And I do like the idea of locating the decoder in a non-powered car. And the bogies on the non-powered cars could also be converted to pick up power....increasing the power pickup reliability!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk
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