2.4 GHz RC Garratt

gregh

electronics, computers and scratchbuilding
1 Nov 2009
3,137
263
Sydney, Australia
www.members.optusnet.com.au
Best answers
0
Country flag
I built this Garratt back in 1998. It was my first attempt at scratchbuilding.
73c2d879d87343d9a815e29ea4f8dacd.jpg

5375b6b7c36c45feb4b5d38dbeabc94d.jpg

(note the 2nd Big Blue Garratt behind ? I like Garratts!)

It is based on two Bachmann 2-4-2 Lynton & Barnstaple ?Lyn? locos. It turned out these motors are quite low voltage but high current types. Each motor takes 1.5 amps but only needs about 6V or so for reasonable (Garratt) speed. When I built it I had no track controller capable of providing 3 amps, so I wired both motors in series. I put in a 7V NiCd battery to power the sound while stopped. But over the years I converted all my locos to battery power RC and the Garratt became an orphan and for the last few years it sat on a shelf in my shed.

When I went to use it recently, ALL the wiring had been affected by this horrible black corrosion. Apparently it starts on the negative battery terminal and works its way along the wires.

Anyhow, while rewiring, I decided to put in RC using my now standard Hobbyking 2.4 GHz stuff.
The 2 tanks already had the 2 sound units in them, so I had to put the batteries and RC stuff in the boiler. I had planned to use two parallel banks of four NiMH cells and put the motors in parallel, BUT luckily I realised in time that this 6V would not be enough for loud sound. So I used 10 cells in series (13V) and left the motors in series.
The 2.4 GHz Rx, ESC and servo for reversing, as well as the batteries, are mounted on a sheet of styrene.

A HobbyKing 6 channel RX, 20A ESC and micro servo with DPDT switch are used. The reversing DPDT switch is superglued to the servo and another SPDT switch glued to it for the head/rear lights control. All 3 elements are hot glued to a piece of 1.5mm styrene. (right end of pic)

The battery cells are all soldered together, but to try to stop the black corrosion I used a 1 cm long brass rod on the neg terminal and put the Polyswitch (?fuse?) in the negative, and covered well with Vaseline. Only 5 years will tell if it works !
As you can see from the pic, I am not the most tidy electrical wirer.
b59dfabde3e247099a94fbf4d3cf7fe7.jpg


The 2300 mAh cells will probably only give about an hour's continuous run, but it meandered around on and off for 2 hours today. Better than sitting on the shelf!

There?s a short video on Youtube here:

http://www.youtube.com/watch?v=le8quQV2YOM < Link To http://www.youtube.com/watch?v=le8quQV2YOM
 

Steve

I didn’t say it was your fault, I said I was b
1 Jan 1970
29,027
285
D.I.L.L.I.G.A.F
Best answers
0
Country flag
Wow , and that was your first scratchbuild , brilliant .
 

corgi

Registered
24 Oct 2009
776
0
Melbourne, Australia
Best answers
0
Greg, that's a pretty good looking Garratt. Is the second blue one a garrett also?

Hope your Lyn motors don't decide to give up the ghost.
 

gregh

electronics, computers and scratchbuilding
1 Nov 2009
3,137
263
Sydney, Australia
www.members.optusnet.com.au
Best answers
0
Country flag

gregh

electronics, computers and scratchbuilding
1 Nov 2009
3,137
263
Sydney, Australia
www.members.optusnet.com.au
Best answers
0
Country flag

eye-kay

Trams, narrow gauge, and anything else on rails
26 Oct 2009
326
0
Warwickshire
Best answers
0
Country flag
gregh said:
Don't know what the youtube link problem is. Worked OK when I uploaded the topic yesterday.
So I'll try again

http://www.youtube.com/watch?v=le8quQV2YOM

Great video Greg. I'm guessing the sound is the Picaxe based one mentioned on your website, with the sound chip for the whistle. Sounds effective. Another thing for me to put on my project list.

Ian
 

gregh

electronics, computers and scratchbuilding
1 Nov 2009
3,137
263
Sydney, Australia
www.members.optusnet.com.au
Best answers
0
Country flag
eye-kay said:
Great video Greg. I'm guessing the sound is the Picaxe based one mentioned on your website, with the sound chip for the whistle. Sounds effective. Another thing for me to put on my project list.

Ian

Thanks. Yes, there's two Picaxe sound units running at slightly different frequencies.
 

robsmorgan

Registered
5 Feb 2010
1,655
0
Ceredigion, Mid Wales, UK
Best answers
0
Good Job Gregh!
Your comment about the electrical deterioration on the negative lines reminds me of a local electrician who used to reckon that the screw securing the negative connection in (any brand) UK power plug had a tendency to become loose over time.... it often is the case whilst changing a fuse, that I find the neg terminal isn't fully tight!
With your professional background you might know if this is possible!

Regards
Bob