Large Scale Central

Servos

In the September issue of Classic Toy Trains, there is an article on using servos to animate items on our layouts. I understand the manual setup using a servo driver. What I would like to learn is how to control a servo remotely using radio control.

Dead easy.

Just plug a servo into a standard Rx. One channel per servo.

You will need 4 x dry cells or rechargeables or a 5 volt UBEC to power each servo position.

Where are these servos located??

I have couplers in engines controlled by servos which are part of my DCC decoder.

Kadee and Phoenix sell systems for the Kadee uncoupler which is a servo controlled coupler. I used one of the Kadees on my Zimo engine decoder and it works perfectly. I then figured I could just use a servo and chain and control a standard Kadee for much less $$.

My largescale engine decoder can control up to 4 servos.

2 servos and a pair of kadees cost less than $20 and I have remote control of these in an engine.

Ok guys do you realize we can’t just say “Dan P.” now? He he he (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-surprised.gif)

So, Dan Padova, Yes I’d have to agree with the question posed by Dan Pierce, it still depends on your application. If you are controlling a loco and it’s accessories then I use a DX6I Tx (Transmitter) and have 6 channels to play with. In this system you just plug each servo into the Rx (receiver) as tony said, and you are ready to go.

For static point on the layout you may be better of with decoders as Dan Pierce suggests. I have no personal experience with decoder use, but can see their advantage in this situation.

Thanks Randy, that’s a start. I do have a Spectrum Dx5 I believe that I use to control my G Scale Graphics Railboss Hobby. So if I take one of the extra receivers i have and plug the servo into it, then bind the receiver to the transmitter, will that get me started ?

By the way, I use servos for animating projects. I’ve built freight cars that dump logs, etc. Until now i had dismantled the servo circuit boards and simply used one of those inexpensive Chinese R/C set-ups to control the servo motor directly. The issue with doing it that way is that you can damage the servo motor if your not careful, depending on the application.

Go to 7:48 in this video. The pipe carrier uses a servo without it’s circuit board to raise the dump bed. In this application not much damage can happen to the servo since it merely rotates 360 degrees. But this video will give you an idea of what I do with servos.

https://youtu.be/nig_ia3X5T4

Now in this application the servo must return to it’s resting position once the pipes are dumped. If I press the transmitter button too long, the motor could possibly be damaged. For this film I simply connected the wires to a power source and changed clarity to bring the servo motor back to resting.

https://youtu.be/HWHF-i-Ef6Q

Dan

For the pipe dump function you could use a receiver driven servo, with the servo connected to the channel on your transmitter that has a self centering stick (spring loaded).

From memory the US use mode 1 so the stick will be on the right, mode 2 its on the left.

Just set up the servo so that in neutral (stick centred) position the pipes are not being tipped, then move the stick to set the tipping position.

To dump the pipes just move the stick either left or right and when the pipes dump release the stick, it will return to centre and the servo will move back to its original position.

You could also use the other stick position to dump the pipe from the other side of the wagon.

Hopefully that makes it a bit clearer and I haven’t confused you to much.

Since I am DCC track powered with Radio control I can make use of my decoders in engines with built in servo control.

I also modified the LGB Dump cars that used their pantograph style drive to work with a digital decoder plus drive status lights.

No more need for LGB’s special track to activate the dump, I can now dump loads anywhere. (maybe lollipops at a show).

Graeme Price said:

Dan

For the pipe dump function you could use a receiver driven servo, with the servo connected to the channel on your transmitter that has a self centering stick (spring loaded).

From memory the US use mode 1 so the stick will be on the right, mode 2 its on the left.

Just set up the servo so that in neutral (stick centred) position the pipes are not being tipped, then move the stick to set the tipping position.

To dump the pipes just move the stick either left or right and when the pipes dump release the stick, it will return to centre and the servo will move back to its original position.

You could also use the other stick position to dump the pipe from the other side of the wagon.

Hopefully that makes it a bit clearer and I haven’t confused you to much.

OK, what I am thinking is that I need a power source at the servo. Shouldn’t there be a receiver at the servo location ? Then I should bind the receiver to the transmitter using the usual binding method, correct ? Never having played with R/C trucks I have little knowledge of how it all works. As I mentioned, the only experience I have with the Spectrum type transmitters and the little receivers is through my experience with G Scale Graphics Railboss Hobby set up.

Dan (Padova) yes, you need 4.8-6Vdc for power, and a receiver. I have used Orange rcvrs (cheap) just make sure it is an aircraft type. Bind it and plug the servo in to whichever channel you like.

Thanks Pete, that seems like it may penetrate my dense skull. I’ll possibly have time to mess around with it today.

https://www.youtube.com/watch?v=GmC4WoLkvBs

instead servos you could use this:

Since my track is DCC powered and radio controlled DCC, I can tap into the track anywhere to operate a servo decoder.

I only have done uncouplers in engines plus the 2 dump cars so far.

If you want total flexibility, and don’t mind doing some light programming and circuit assembly, the Arduino is a great tool for driving servos. The NmraDcc library provides the ability to receive and parse DCC packets, and then you can do whatever you want with the information.

Below is a little video of an Arduino Pro Mini (the blue board in the center of the green protoboard) that I’m using to drive two Kadee 11220 couplers, based on function on/off DCC commands. This tiny board could potentially drive 17 servos.

Hmm another electronic geek … Dave watch out!

Sean McGillicuddy said:

Hmm another electronic geek … Dave watch out!

Thank goodness. The more the merrier :slight_smile:

Martin

http://martinsant.net/