RC for a little diesel

[gregh]

A GOOD friend has just given me a little diesel loco. It?s so ugly, it?s cute. It?s been scratchbuilt on an LGB motor block labeled 2317/6 which seems to be a block from a powered Tender. The builder obviously used an LGB steam loco cab and added a diesel hood. The cab arrangement is weird in that it has 2 side doors with seats behind them and then an open rear as per a steam tender loco. I have to decide whether to block up that rear opening or not.

Anyhow, I like it, so I need to do some battery power?.

Now the real problems are:-
There's no room for a speaker, except maybe in the cab roof.
All the 'cavities' are just too small for AA batteries. The space under the hood is only 90Lx40Wx48H. The 90mm long dimension is just too short for two cells along. It?s 48mm high where 55mm would have allowed cells to stand up. etc, etc?.
(That?s why when I build my own locos, they are dimensioned to fit batteries! )

I figured I had two options:-

A. Just use a simple forward/off/reverse switch. I measured that 5 cells will be sufficient to give about 25kph. I can fit the 5 batteries and switch in the hood OK.

B. Go for 2.4GHz full RC. If I use an existing transmitter, I only need a Receiver, ESC and servo+switch for direction. I?d need min 6 cells for this. But I can?t fit all that in the hood with the batteries. So I?ll have to put 3 cells in the cab disguised as tanks or something. Two more mounted vertically in the little side ?cupboards? ? I need to drill holes in the baseplate so they extend below the base. That leaves one or maybe 2 or 3 cells under the hood. If I can fit 3, I?ll have my standard 8 cells arrangement with simpler charging.
I even went searching the Internet for LiPo batteries which would fit better, but no luck.

In both cases, if I can fit a speaker in the cab roof, and it has enough volume to be worthwhile, I can use my home-made Picaxe sound system and it should fit in the hood in both cases. That will come later.

For the extra $25, full RC seems the way to go. So this is how it MAY fit.

More to follow?????

 

[gregh]

I finished up with only 1 cell under the hood for a total of six, or about 8V. The Polyswitch ?circuit breaker? is soldered to the negative cell.

I expoxied the DPDT reversing switch to the servo and the servo to the receiver.
I made up the operating cam from white styrene ? this always takes a bit of trial and error.

I then glued the ESC to the side of the Rx/servo for a compact unit.
See my webpage for more general details.
http://www.members.optusnet.com.au/satr/2point4GHz.htm


I made copper door handles to be the charging lugs where I attach my charger?s alligator clips. You can see the pos one in this pic.

The big mistake I made was connecting the switch between cells 3 & 4 as it was ?easy?. (usually the switch is in the positive wire.) I figured it made no difference. It doesn?t EXCEPT that now I have to have the unit turned on to be able to charge. So next time the thing?s disassembled, I?ll rewire it.

There?s still no sound until I can find a small enough speaker.

I?m still trying to decide what to do with the cab rear opening ? maybe a wooden gate like this ??

 

[Andrew]

Hello Greg, looks good, I like the wooden gate.
On a seperate question, What value do you suggest for the poly switch circuit breaker? Or is it not a factor as it would work regardless in anything up to 12 volts?
Can it be soldered onto the positive or negative side of batteries or it won't matter as long as it is there?
Regards Andrew
Sandbar & Mudcrab Railway

 

[Moonraker]

Greg,

I have a small speaker shown below which sells for A$6. The size is 32mm long x 28mm wide x 15mm high and it can be used with the MyLocoSound diesel soundcard which is 64mm x 38mm x 13mm. Further details are at http://www.mylocosound.com/ < Link To www.mylocosound.com.

Regards
Peter


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[gregh]

Hello Greg, looks good, I like the wooden gate.
On a seperate question, What value do you suggest for the poly switch circuit breaker? Or is it not a factor as it would work regardless in anything up to 12 volts?
Can it be soldered onto the positive or negative side of batteries or it won't matter as long as it is there?
Regards Andrew
Sandbar & Mudcrab Railway

I use a 3.7Amp Polyswitch for most of my locos. Which is plenty for the typical 1.5A max most locos take. It's only to protect against short circuits which will give 10s of amps.
They can be mounted in positive or negative as long as close to battery (to detect ALL shorts), but I try to solder mine on the negative battery terminal. This is just one of those belts & braces ideas that may not be useful, but I have had the dreaded ' black wire corrosion" in some locos. It seems to start on the negative and progress along the PVC insulation. So I reckon if I put a polyswitch in it can't 'creep'.

 

[gregh]

Greg,

I have a small speaker shown below which sells for A$6. The size is 32mm long x 28mm wide x 15mm high and it can be used with the MyLocoSound diesel soundcard which is 64mm x 38mm x 13mm. Further details are at http://www.mylocosound.com/ < Link To www.mylocosound.com.

Regards
Peter

Thanks Peter. It looks like it's one of those 1" mylar units, is it? Or is it a 'real' speaker. The mylar types never have enough volume for the great outdoors for me. But maybe I should try one in a box like your pic. I can probably get a real speaker from Jaycar, just havn't got there yet.

 

[Andrew]

Thank Greg. Cheers Andrew.

 

[Moonraker]

Greg,

I agree that, if you want high volumes outdoors then the speaker I suggested is not the one to go for. We normally use them for indoor H0/00 railways because they fit in the rolling stock and give a good quality sound.

For high volumes outdoors, I normally use iPod extension speakers...they're great but rather bigger of course.

Regards
Peter

 

[Bram]

It might seem a daft question Greg, but what is the servo for?

 

[whatlep]

Excellent article. Neat job too. I especially like use of the pallet to block the rear access. Exactly what I imagine an impoverished industrial line would do!

 

[gregh]

It might seem a daft question Greg, but what is the servo for?

I use a servo with a DPDT switch glued to the side of it to do reversing. It's a very simple and cheap way of doing it. See my pages here for a better description.
http://www.members.optusnet.com.au/satr/2point4GHz.htm#direction

I know there are electronic ways, but they cost lots more AND you get more voltage drop through them. As I try to use the minimum battery voltage possible, I don't want to waste any volts! And I'm a cheapskate!

Excellent article. Neat job too. I especially like use of the pallet to block the rear access. Exactly what I imagine an impoverished industrial line would do!

Thanks. I can't even take credit for the idea. I was bemoaning the fact to a mate that I'd have to block the opening with styrene and then try to match the paint colour, and he suggested a gate. I think it's a perfect solution and much easier too.

 

[gregh]

Greg,

I agree that, if you want high volumes outdoors then the speaker I suggested is not the one to go for. We normally use them for indoor H0/00 railways because they fit in the rolling stock and give a good quality sound.

For high volumes outdoors, I normally use iPod extension speakers...they're great but rather bigger of course.

Regards
Peter

I made up a twin Mylar speaker unit in a styrene box. I stuck a piece of sheet steel to the roof of the cab and the speaker magnets hold it in place! Still not great volume. Low frequency diesel sounds are much harder to reproduce than steam sounds.