Budget Battery Powered 00 Gauge Loco

[Robin2]

If you have to extend the motor shaft, you can do this with a piece of brass tube with a suitable internal diameter - if of course you can find a suitable size.

 

The little motors I am using have a 1mm shaft and in spite of having a range of small tube sizes I have none that is a sufficiently close fit to be concentric - hence the drilling.

 

It is probably slightly easier to drill out a tube to a slightly larger size than drilling a concentric hole in solid brass bar. However if the bar is rotated and the drill held steady the hole is pretty much guaranteed to be concentric - or the drill will break

 

...R

Edited June 12, 2017 by Robin2

[BG John]

I had a rather frustrating day today, trying to get nRF2401s to talk to each other. I followed the simple example in Robin's Arduino Forum topic, but couldn't get it to work. I eventually traced it to the sketch hanging while trying to send a message. A number of other people have reported the same problem in the topic, with a variety of causes suggested. The most likely one seems to be an incompatibility with my cheap Chinese Unos. The only other Uno I have is a Geekcreit, so I tried that, and it seemed to work, but as I've only got one, I couldn't get it to talk to another one that works! I'll try it with a Nano, or the two makes of Pro Mini I've got, but need to clear some space so I can solder the headers on them first.

 

Anyway, if there's likely to be compatibility problems, I'm tempted to try Robin's approach, and use just an ATTiny or ATMega chip. It means I can fit them in a smaller space, and it's something interesting to learn. There's useful information online about how to do it. As Robin suggested, I'll probably start with an ATMega328P, as they're big, then work my way down in size until they get too small for me!

 

At the moment I'm building the electronics for one of my DC EM layouts, that I want to operate from a wireless control panel. It's a good place to start, as it has all the elements of an RC loco, except the battery, but on a bigger scale. To start with, I'm using infrared control, and will add radio later, when I've got the layout working. I just wanted to get an nRF2401 working so I could attach it to the Nano I'll be using, and get everything else connected to the right pins. I'm now inclined to make the Rx a separate item, with it's own microcontroller, so all I'll need at the moment is to reserve one pin on the Nano for an input from the Rx. It only needs to send brief codes that are mostly the same as those from the IR controller, and the Nano can run the same sketch to handle either. I think the only real difference will be loco speed control, where the RC handset will have a potentiometer, but the IR one uses + and - buttons to change speed. I've got that bit working, but it's not as user friendly as a pot would be.

 

The problem with making the Rx smaller, is that I'll be tempted to put it in more things! RC was just going to be for my O gauge layout, but I'm tempted to use it on the O-16.5 one I'm planning, plus some of my 4mm layouts. And then there's road vehicles in 4mm and 7mm scales!

[Robin2]

It's probably easier to help with the programming and nRF24 if you start a question on the Arduino Forum. The examples should work.

 

...R

[BG John]

It's probably easier to help with the programming and nRF24 if you start a question on the Arduino Forum. The examples should work.

 

...R

I'm sure it does work, but apparently not with all Unos! You didn't reply to the comments on the problem on the topic you started . I see you've now closed the discussion.

[Robin2]

I'm sure it does work, but apparently not with all Unos! You didn't reply to the comments on the problem on the topic you started . I see you've now closed the discussion.

Sorry about that. The problem is that I don't have time to monitor every section of the Arduino Forum and I had thought all along that the tutorial Thread was locked. If you post a question in the Networking section I will see it.

 

The reason for locking the tutorial Thread is to stop it becoming an unwieldy length - a lesson that could usefully be learned for some of the Threads on this Forum - for example about the Silhouette cutter .  There is no intention to close discussion about the nRF24 - the more the merrier.

 

...R

[BG John]

I think I've got a revised plan for my current project, so I'll get on with building it with just an input available for messages from the Rx. I'll do some more experimenting to see if the nRF24 works with cheap Nanos and Pro Minis. If it does, I'll use them to get started. If not, I'll get the bits together to program ATMegas and ATTinys. If I build a separate Rx for this project, it will be a step towards RC locos, rather than just being integrated into something bigger.

 

I don't think there's anything I need to ask at the moment. I posted my comments more as a warning that the nRF24s don't seem to work with all Arduinos, which might save someone wasting time trying to get them to work, when it may be the hardware and not them.

[BG John]

I've got my Geekcreit Uno and a cheap Nano talking to each other, using Robin's simple sketches. No luck with the Pro Minis yet, as I'm having trouble programming them. That's at least partly due to buying the wrong wrong USB to TTL external adaptor though, so I'll wait for another one to arrive before I try again. At least it's progress, and I'm a bit nearer to getting a loco running!

[Robin2]

That's at least partly due to buying the wrong wrong USB to TTL external adaptor though

What's wrong with it?

 

I got some new ones from Hobby Components today but I have not tried them beyond checking that my laptop recognizes them.

 

...R

[BG John]

It doesn't have a DTR connection, so doesn't reset the Pro Mini when it's supposed to. Some people seem to get round that by pressing Reset at exactly the right time, but it won't work for me. It also won't be much help when the thing is buried inside a loco, and I want to update the software! The error message I'm getting is about the programmer not responding. It seems logical to deal with the hardware issue before sorting any other problems, so I've ordered one from the UK rather than China, so I only have to wait a few days.

[Robin2]

It doesn't have a DTR connection,

My new ones have DTR but the older one doesn't. However it has RTS which causes the reset and which the new one does not have.

 

I will explore them tomorrow.

 

The trick with the reset button is timing   You need to press it just as the compile phase finishes.

 

...R

[BG John]

Inspired by getting two nRF24L01s to talk to each other, and the title of this topic, I thought I'd start off by using RC on my OO layout, so I don't have to bother finishing the wiring, and fitting switches to the point servos. In fact, it would be fully operational right now (with hand operated points) if I had a RC loco!

 

So I dismantled my two OO locos, to see what I could do with them. My Mainline 56xx 0-6-2T seems to have room to get everything in, and looks promising. The only concern is the non standard motor, and what voltage and current it needs. Small 3.7v step up convertors don't produce a lot of amps at 12v, and those that do won't fit. I didn't want to build a new chassis for it. Then I looked inside my Bachmann 57xx, and there's no room to get anything in. I don't think I could cut out enough of the chassis casting, and remove enough of the other weights in the body, to make it work. That definitely seems to be a new chassis job.

 

I could try to use both chassis in O-16.5 locos, if I can build some that are big enough to get the RC gear in, and make new chassis for the OO locos, but that pushes up the cost, and creates extra work. So I'll need to think about it. Both locos have split chassis, and although they'll no longer serve the purpose of picking up track power, I'm not sure they'd survive a major rebuilt so I could fit low voltage motors.

 

Has anyone tried to convert these locos, or anything similar?

[fallen]

I have converted an old design split chassis Bachmann Stanier 2-6-2T (OO). I carved enough out of the weight in the side tanks to fit a 150mAh (I think, or thereabouts) battery on each side, giving me a 2S setup, which was Ok to power the original motor. The receiver went in the cab and the switch and charging connector under the cab floor hidden by the steps to the cab - my usual place to put these.

 

The tricky bit with the split chassis was that the two chassis castings clamped the motor and made contact with the motor terminals via short springs. I cut away enough of the casting to break the contact without cutting so much that the motor became loose. This allows the receiver to be wired directly to the motor terminals.

 

It looked good when finished and ran at a nice speed for an hour or two on a full charge. I tested it on a club layout as I don't have an OO layout myself.

 

I'd suggest trying various voltages with the chassis to see how many batteries you need, and take it from there.

 

Frank

[BG John]

I was thinking overnight that I'd reassemble both chassis, and put them on my rolling road, where I can connect them to a test setup of an Arduino and motor controller. I can then run them at various voltages and measure the current. I could even do clever stuff like reading the speed of the driving wheels, to get a voltage that suits my planned use.

 

The main problem with the Bachmann loco is the pannier tanks, as they don't have as much space as side tanks. The space is filled with a U shaped weight that wraps round inside the smokebox. It must have been fitted before the body was assembled, and I'm not sure there would be space for batteries of circuit boards if I do the necessary surgery to remove it. I'm thinking that building a new chassis might be easier! With the 56xx, I think I just need to find out what voltage and current it needs, and there may well be room for the necessary batteries. I was hoping to keep my first locos to a 1S setup for simplicity though.

 

I haven't mentioned the Heljan railbus yet!

[Robin2]

If you are not relying on electrical contact with the track a lot of the weight is probably unnecessary and counterproductive.

 

 

...R

[BG John]

It's only a shunting layout, so I don't need a lot of adhesion for pulling long trains either. I think it's more a question of how much weight I can remove without the chassis falling apart! Both locos are pretty heavy, and have big weights in the bunker that take up a lot of potential battery space. It's getting them out without trashing the body that's the challenge! It's a shame I haven't got an oldish Hornby loco to run on this layout, as it could be much easier.

[fallen]

HobbyKing do some round cells that might fit in the pannier tanks, depending on how big they are of course. They are more the shape of a pannier than the flat ones. If you can get the weight out!

 

Eg:

 

https://hobbyking.com/en_us/turnigy-nano-tech-270mah-1s-15c-round-cell.html

 

It you are setting up some tests it would be useful to measure the current if you can. This will tell you how big a bettery you need.

 

Robin is right, most locos need weight as much for electrical contact as adhesion, with radio control this isn't an issue so the locos can be lighter.

 

Frank

[Robin2]

@CME and BottleWasher sent me a PM with the following question and agreed that I could post the question and my reply here in case it is of interest to others

Question...

What type of batteries have you settled on using and if they are LiPo or LiIon, do you charge them onboard the loco?

 

Reply ...

 

I have decided to use 1S LiPos after dabbling for a while with the idea of using 2S LiPos. But I want a simple charging system so I can drive a loco into a "top-up" siding and I figured the balanced charging of 2S LiPos was going to be too much trouble with a too great risk of short circuits.

 

Using a 1S LiPo also gives more choice about battery size.

 

The downside is that I need to use a suitable low-voltage motor.

 

I haven't got details of the onboard charging figured out yet - as usual I am easily distracted - so I have just been charging the battery out of the loco.

 

With earlier N-Gauge trials I was picking up the charge voltage with the wheels but that meant I needed a bridge rectifier in case the loco was put on the track the wrong way round and it meant that the loco would be incompatible with a regular club layout. My present thinking is to have no pickups from the wheels.

 

...R

[BG John]

HobbyKing do some round cells that might fit in the pannier tanks, depending on how big they are of course. They are more the shape of a pannier than the flat ones. If you can get the weight out!

 

Eg:

 

https://hobbyking.com/en_us/turnigy-nano-tech-270mah-1s-15c-round-cell.html

 

It you are setting up some tests it would be useful to measure the current if you can. This will tell you how big a bettery you need.

 

Robin is right, most locos need weight as much for electrical contact as adhesion, with radio control this isn't an issue so the locos can be lighter.

 

Frank

I've got a round battery, but it's disappeared into the pile of stuff on my workbench! When I find it, I'll see if it fits. I bought it to fit in the boiler/smokebox of another loco I was thinking of converting.

 

I've got a MAX471 current measuring board waiting for the header pins to be soldered on, sitting on the breadboard I'm putting the tester together on .

[BG John]

 

@CME and BottleWasher sent me a PM with the following question and agreed that I could post the question and my reply here in case it is of interest to others

Question...

Reply ...

 

I have decided to use 1S LiPos after dabbling for a while with the idea of using 2S LiPos. But I want a simple charging system so I can drive a loco into a "top-up" siding and I figured the balanced charging of 2S LiPos was going to be too much trouble with a too great risk of short circuits.

 

Using a 1S LiPo also gives more choice about battery size.

 

The downside is that I need to use a suitable low-voltage motor.

 

I haven't got details of the onboard charging figured out yet - as usual I am easily distracted - so I have just been charging the battery out of the loco.

 

With earlier N-Gauge trials I was picking up the charge voltage with the wheels but that meant I needed a bridge rectifier in case the loco was put on the track the wrong way round and it meant that the loco would be incompatible with a regular club layout. My present thinking is to have no pickups from the wheels.

 

...R

 

I've got some of these TP4056 boards to try. I'm hoping to be able to use 1S LiPos to keep charging simple too. If these work I can just plug in a USB cable. I seem to have picked two difficult locos to start with, where fitting a low voltage motor involves a major chassis rebuild!

[CME and Bottlewasher]

I've got some of these TP4056 boards to try. I'm hoping to be able to use 1S LiPos to keep charging simple too. If these work I can just plug in a USB cable. I seem to have picked two difficult locos to start with, where fitting a low voltage motor involves a major chassis rebuild!

Hi Guys,

 

Thanks for Posting my PM.

 

I wasnt getting updates to this fascinating Thread, so Im catching up.

 

Charging onboard is a must AFAIC as taking detailed locos apart will be a chore/risky (damage to model). I have recently purchased a charger/conditioner for my RC cars/boats-mind you one appears to need a degree in electronics to be able to operate the thing-so fly/charging leads may be an option (it caters for NiCad/NiMh LiPo and LiIon) and using well made patch leads etc helps reduce the risk of shorts. But then there is the problem of heat generation during charging with the battery in situ as well as not being able to charge it on a metal plate/in a metal box (as advised by many). Having said this Im attempting to type this on a mobile phone, whilst its being charged and it's made mainly from plastic!

 

Confussed?? I am!

 

Kindest to all,

 

CME.

[BG John]

The scary warnings about charging Lipos in fireproof bags worry me, especially after seeing one go up in flames on YouTube. And we put these things inside our plastic models inside our house .

[Robin2]

But then there is the problem of heat generation during charging with the battery in situ

The R/C car, boat and plane fraternity usually want fast charging and that is what causes the heat. With slow charge rate (perhaps 1C) there is unlikely to be any significant temperature rise. It may be that the charger you have is not ideal for in-situ charging of model trains.

 

...R

[CME and Bottlewasher]

The scary warnings about charging Lipos in fireproof bags worry me, especially after seeing one go up in flames on YouTube. And we put these things inside our plastic models inside our house .

Hi John

 

Yes and we have them in phones, vacuum cleaners, garden equipment, computers etc....so a calculated risk?.........

The R/C car, boat and plane fraternity usually want fast charging and that is what causes the heat. With slow charge rate (perhaps 1C) there is unlikely to be any significant temperature rise. It may be that the charger you have is not ideal for in-situ charging of model trains.

 

...R

Yes Robin, those are very good points, I believe that my new charger is fast or slow at the flick of a switch.....havent had time to check it out though....Im usually okay with tech, but the flow-charts in the handbook have gone over my head.....life used to be so much simpler!

 

Circling back to John's comments again, the batteries Ive seen go for a burton, are often due to shorts caused by a nest of DIY wiring, instead of decent connectors/wiring practices. I also wonder if battery quality plays a part too?

 

ATVB

 

CME

Edited July 10, 2017 by CME and Bottlewasher

[BG John]

Lipo batteries in consumer products are (hopefully) designed and built by experts, and the companies have product liability insurance! I'm going to be very cautious fitting the first few .

[Robin2]

Lipo batteries in consumer products are (hopefully) designed and built by experts,

Like Samsung and Boeing?

 

...R