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Robin2

Budget Battery Powered 00 Gauge Loco

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One of my potentially challenging conversions is a OO Bachmann Pannier, if I do start converting 4mm stuff. Most of the other 4mm locos can have smaller motors fitted to make more space, and some need a new chassis. I've also got an Oxford Radial, but haven't looked inside that yet. I'd be quite happy to plug the 4mm locos into a charger, so it's only the O gauge ones I'd like automated charging for.

 

I've just ordered a few cheap (for a UK supplier) 6 volt motors to experiment with. No idea if they'll be any good, but hopefully they'll be OK for the learning stage at least.

 

The problem with converting 4mm locos is that I'm working on the Arduino based DC control systems for the layouts as my first project, so by the time I have the RC working, I'll have all the layouts wired for DC. I'm having to reach over a pile of Arduino bits, where I'm assembling the first one, to type this!

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I've just ordered a few cheap (for a UK supplier) 6 volt motors to experiment with.

Would you mind posting a link to the supplier and the models you have ordered. I am always on the lookout for a source for motors.

 

...R

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These:

http://www.ebay.co.uk/itm/132178960000

 

As I said, I don't know if they'll be any good, but wanted something to experiment with. They're wider than OO gauge back to back, so that may limit their use, even if they run well.

 

I couldn't find much available in the UK when I searched today. When I'm not looking I find loads!

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Thanks - much appreciated. I have a few of those in two different voltage ratings. The price is attractive but they are rather on the large size for an 00 Gauge tank loco. On the plus side they have 2mm shafts that are a decent length.

 

The N20 sized motors only have 1mm shafts that are about  3mm long so I have had to make an adapter to bring them up to 2mm diameter and about 20mm long.

 

I have been wondering if a hacksaw might bring the 130 motors down to a more acceptable size :)

 

And, as an update to Reply #14 I think I have figured out how to make the N20 motor run at a sufficiently low speed with a 48:1 gear ratio - by increasing the PWM frequency.

 

...R

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.I can provide the build info but at this stage it may be easier for me to provide you "kits" at the cost price since I have lots of spares.  You will spend less time sourcing components and more time building/using the setup.  It would be very useful if you can provide some feedback on this forum or other suitable place. 

 

 

Michael, I am modelling in 7mm and am keen to develop a BPRC solution - where /when might your design be available to review in more detail and can you provide more information on possible "kits" for the hardware please?

 

Chris

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I'd have probably jumped at the chance of a kit to help me get started a few weeks ago, but as I've got most of the parts I'll need already, or they're in the post, what I need is knowledge. I think the great thing about this technology is that it's not a one size fits all solution, and we can all do whatever suits our particular need. What I've found in my very short time using Arduinos, is that all the information I've needed so far is out there somewhere, and when I want to do something, I can Google it to find an answer that I can copy, and then adapt.

 

I don't think it's quite so easy with using RC on model railways, or I haven't found it yet, so I think all of us sharing what we know is a good way to go. I'm certainly happy to do it once I've achieved something. I just need a bit more knowledge to get started.

 

Although I was planning to use RC just for my O gauge, the idea is spreading! My OO layout is the most complex layout I'm building, with the huge total of seven points. I wired the frogs while I was track laying, but now I've decided to changed from Peco point motors to Arduino controlled servos, I'm thinking I may as well forget finishing the wiring and go for RC instead. So OO gauge locos are now interesting me more. I'll need to convert a Bachmann Pannier and a Mainline 56xx 0-6-2T. The 56xx was bought on eBay for around half the usual secondhand price, so I'm not bothered about doing a total chassis rebuild if necessary, maybe with a 6 volt, or less motor. If I can convert the Pannier chassis to EM, I may just build a new chassis for that, as my EM and P4 layouts will stay DC. The exception on the OO layout is my Heljan Railbus, that I'm reluctant to mess around with, at least for now. I can wire the track that will run on for DC, with only one switchable frog, and the other points it runs over can be wired to run DC is just one direction.

 

I think the opposite may apply on my planned O-16.5 layout, that I still intend to run on DC, but it would be useful to have one RC loco for shunting around the station, as it reduces, or may totally eliminate, the need for section switches.

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I just realized I forgot to include a link to the Deltang website in my original post. If you don't mind spending a little more those wireless modules are really small and will easily fit into an 00 Gauge loco.

 

...R

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A "little more"!!!! I got into Arduinos because of your £8 Rx, compared to over £30 for Deltang. At Deltang prices I'd almost definitely, but not quite, decided to use RC for my O gauge, but it's only spreading to 4mm scale as well because of the DIY prices!

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A "little more"!!!! I got into Arduinos because of your £8 Rx, compared to over £30 for Deltang. At Deltang prices I'd almost definitely, but not quite, decided to use RC for my O gauge, but it's only spreading to 4mm scale as well because of the DIY prices!

 

Not only price.  As there is generally more railway traffic going on 4 mm scale layouts the nature of the TX is very important: it determines how trains are operated.  Do you want cab control or one master computer controller, or both?  A low-level approach gives this flexibility whereas I believe the existing products, particularly because they are closed-source, do not. 

 

However, please correct me if I am wrong!

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Not only price.  As there is generally more railway traffic going on 4 mm scale layouts the nature of the TX is very important: it determines how trains are operated.  Do you want cab control or one master computer controller, or both?  A low-level approach gives this flexibility whereas I believe the existing products, particularly because they are closed-source, do not. 

 

However, please correct me if I am wrong!

I totally agree. All my layouts are small, and of the one engine in steam variety, so complex operation isn't a requirement, and DCC is unnecessary unless I want expensive sound. A DIY approach to RC means that I can integrate it into the rest of the system. The system can send commands to the loco, as well as the human operator, and potentially receive feedback from it. I can do things like having an automatic stop in the fiddle yard, where I may not be able to see where the train is, and dead track sections are no use. I'm hoping I can develop the skill to have a fully automated fiddle yard on one or two layouts, where the system will need to drive the loco itself. I'd also like to work towards full layout automation, that I can switch to when I don't want to control it manually. The RC just becomes part of the system, rather than something separate from it. I suppose DCC can do that too, but only with masses of wiring.

 

I'm planning wireless remote control on a couple of the DC layouts that are ready to get working. To start with I'm going to use infrared, but hope to change that to RC later, so the RC handset will need to be a complete handheld control panel. I've built handheld panels in the past, but attached to the layout by a ribbon cable, with no electronics. This makes me think that I need separate RC links from handheld controller to the layout, and from the layout to the locos. What I like is being able to break a lot of this down into small modules, that are linked mostly by software, and just a few wires. The modules may be ones I build myself, or an off the shelf board, or combination of boards.

 

The potential is limited only by our imagination, and by the skills we can develop, and only a little bit by money!

 

I've got a long way to go though. I'm currently on my first project, which is building the controls for Abbotsbridge. I've worked out that the system I need for two other layouts is almost identical, so I'm building a standard system that suits all three of them. The first is going very slowly, but hopefully once that's done I can build the others quite quickly. The main difference in them is the number of points they control. This is all DC, and not wireless. Wireless and RC comes soon I hope!

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A "little more"!!!! I got into Arduinos because of your £8 Rx, compared to over £30 for Deltang

OK. Don't eat me :)  I just wanted to make sure I had covered all the options.

 

In the same spirit most of the Deltang units use Atmega328 microprocessors and, with a bit of effort, can be programmed using the Arduino system. I built a PC train control system using one of the Deltang units connected to my laptop to talk to the other units in the locos.

 

...R

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The 99p L298 boards without heatsinks I ordered from China arrived today. They're about 25mm x 20mm x 7mm, so may be small enough to fit in some locos. The ones with heatsinks are 43mm x 43mm x 32mm in comparison.

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I think you will need to add heatsinks. But maybe to a more convenient shape than the "standard" ones.

 

...R

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I ordered them for loco controllers, but will probably try them for other things, like stepper motors, where they won't run for very long. I though they were worth mentioning though, due to the size.

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Being a cheapskate, I searched for alternative DRV8833 boards to the Polulu ones that Robin is using, and found some on Aliexpress for £0.95, about ¼ of the price of Polulus. Being my first Aliexpress order, I paid extra for tracked delivery, and they arrived very quickly. I don't know how they compare for quality.
 
This is a size comparison, from left to right:
Outline of Polulu DRV8833 - https://www.pololu.com/product/2130
Aliexpress DRV8833 - https://www.aliexpress.com/item/DRV8833-2Channel-DC-Motor-Driver-Module-Board-1-5A-3V-10V/32709812962.html
L298N - http://www.ebay.co.uk/itm/311622397429
L298N with heatsink - http://www.ebay.co.uk/itm/142286764490
 
post-7091-0-12101900-1494500034.jpg

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I like to support local suppliers.

 

Note that the DRV8833 has a max voltage of 10v IIRC - and also a low minimum voltage so it can be used with a 1S LiPo.

 

...R

Edited by Robin2

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I need to support my bank account!!

I have no wish or intention of criticising your (or any other person's) personal spending behaviour.

 

However I am always reminded of the many people who complained when their local mom-n-pop grocery store closed precisely because the people who were now complaining had chosen to shop in the new superstore to save a few pennies.

 

Another example was the delegation of members of parliament who came to see the Transport Minister to complain about the closure of their local train service. But the entire delegation had travelled to the meeting by car.

 

It won't be long before manufacturing costs China are similar to those in Europe or the USA but the ability to manufacture products in Europe and the USA will have been lost and there will be no competition to keep Chinese prices down. When I first travelled to Brussels as a junior Irish civil servant the prices in Brussels seemed incredibly high. By the time I retired Dublin was dearer than Brussels.

 

...R

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Having lost a lot of money in my failed attempt to help people and make the world a better place, I've got to look after the pennies so they last until I'm pushing up the daisies. I've tried to do my bit to support local economies, even if it wasn't successful. Until I get my life back on track, the modelling I'm trying to do is about all that's keeping me sane, but I have to really try to keep the cost down. I'm actually buying quite a lot from UK based eBay sellers, when I need things quickly, and buying the stuff there's no rush for from China.

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Until I get my life back on track, ...

I do have some experience of that.

 

And perhaps it is reflected in my cheapskate approach of trying to build locos rather than buying them. I am amazed at the enthusiasm to splash out £150 on every new thing that comes along just to admire all the fine detail that makes each successive model more expensive. There does not seem to be any sense of achievement in that.

 

...R

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And all these £150 locos are made in China, along with lots of other model railway stuff. Buying them in the UK does support sales businesses, but does nothing to support local manufacture. Buying a few sheets of mount board in the local craft shop doesn't do much for our economy either!

 

I've bought some new RTR locos, but don't intend to buy any more. Other locos I've bought have been mostly secondhand on eBay, for bashing into something else.

 

Anyway, are we all going to carry on discussing how to make locos run off little Chinese made bits of electronics with no wires? I've now got transceivers and motor drivers, and can connect them to an Uno, until my Pro Minis arrive (from China!).

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 I've now got transceivers and motor drivers, and can connect them to an Uno,

Have fun

 

Must go and re-program my Attiny and see if I can get good low speed running.

 

Although it is not specific to BPR/C it occurred to me while doing some testing that running at a too-low speed is just as unrealistic as running at a too-high speed. It reminded me of how film directors compress time - films do not normally run in real time but we think they do while we watch each scene.

 

...R

Edited by Robin2

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I won't be doing much to it for a while, as I've got a desk covered with a part built control system for a DC layout. When that's done, I've got two more very similar ones to build. Then I can start playing with RC.

 

It's odd that we drastically compress the length of our layouts, so that a loco travelling at scale speed gets from one end of the station to the other much quicker than in real life. Then we speed it up even more!

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Hooray. (referring back to Replies #14 and #29)  I now have my loco working nice and slowly with the small N20 motor.

 

What had been preventing slow running was the 0.1µF suppression capacitors that I had connected to the motor terminals. In earlier trials they had appeared essential to prevent interference with the motor speed detection. I'm guessing that the capacitors were damping the effect of the PWM and this was even more pronounced when I increased the PWM frequency.

 

...R

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Xc=1/2PifC

 

Xc is reactance or the effective capacitors resistance to AC wave forms.

 

As you increase f (the frequency) then you are effectively reduce the reactance across the motor terminals.

(Just as if you you put a low value resister across the motor so that it took all the current instead!)

 

 

Hows the motor temperature with the higher frequency PWM?

 

 

Kev.

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