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.
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Seems to me the hobby servo application started with radio control (RC) planes/cars - wireless by necessity. I think your best bet would be the vast literature/tutorials and product choices in RC servo transmitters and receivers.
If You could tell me exactly what your wanting to animate I can then probably tell you what you will need and how to go about doing it. To use a servo with a radio you'll also need a receiver to link the radio to the servo also you will need to figure out what kind of servo you need RC or robotic? I've been in RC for years. I currently have almost thirty giant scale airplanes, a DJI Phantom 3, 1/6 scale
race boat and a 1/16 scale military tank.
Servos even have their own magazine. Here's a link. I read their sister magazine, Nuts & Volts. A lot of it is over my head, but occasionally something sticks. They also have some interesting projects and I think Servo does too.
I haven't looked at one of these for a while, but they may have some info on their website. Possibly a starting point and also asking RustyRail above?
Better to control them with a micro-controller, and a switch. Then work on interfacing the micro-controller with the command systems. Currently working on a servo switch machine project. That will end up being controlled wirelessly through the DCS handheld via the AIU.
There are a lot of ready-made products from the RC Auto/Plane/Boat market that would give you remote control of a servo and likely do a very good job of it.
For my money, however, I find it hard to beat using inexpensive micro-controllers such as Arduino clones, and the even less expensive radio boards that can be used with them. For most servos you could get by with a small buck converter power supply($1.50), an Arduino Nano clone($2.25), and an nRF24L01+ radio($1.00) on each device you want to control. In your remote or control panel you would need an additional Arduino and nRF24 radio. For something as simple as this one could easily modify the example code that comes with the radio's library. There is an example there that uses 2 potentiometers on one end to control 2 servo's on a second Arduino, if I recall.
Also, if you have several devices near each other a single set of power supply, micro-controller, and radio could be used to control a dozen servos...(or more if you used a larger micro-controller board.)
In open air the nRF24 radio is good for at least 100 feet, however in the real world they will perform pretty much identical to LionChief locomotives for effective range. They also make this same radio in a more powerful version with an external antenna that has been proven to work at ranges over half a mile, though these versions cost about $10, and are a bit larger.
JGL
The pieces are cheap John, but then you have to do all the software to actually use this setup. 
Well, Like I said, if it were me, I'd just modify one of the examples included with one of the libraries for these radios. Yes, one would need to have a basic understanding of how to program these things, but beyond that, there is not much to it.
Also, as is the case most times when I suggest using Arduino for something, I put the info out there of what can be done, then will be happy to go into further detail on how later on, if there is interest in it as a solution. No point in writing the code if no one wants to use it.
JGL
Well now, if you're going to write the application... 
Whether wireless or wired, a handy tool for messing with servos to adjust linkages, arms, etc. to get the motion "just right" is this $1 (free shipping from Asia) servo tester I described in this previous servo thread:
https://ogrforum.com/topic/making-things-move
As previously requested additional info on exactly what is being attempted would focus responses. For example, if the only function of the "wireless" servo link is to open/close a door or to throw a turnout straight/curved, that could be fairly simple/inexpensive RC components.
I bought that very tester, it is useful for tuning the servos. For my Tie-Jector command upgrade, it was useful to test my actuator before I committed to my simple timer board.
gunrunnerjohn posted:...For my Tie-Jector command upgrade, it was useful to test my actuator before I committed to my simple timer board.
Exactly. IIRC you used a 555 generating one of two pulse-widths? Hard to believe they are down to 7 cents each now!
I realize your Tie-Jector (a clever use of the fast servo speed) is under command control but illustrates the point that depending on application, "wireless" or remote control of servo action may be a on/off, left/right, up/down, eject/retract, etc. which can be a simple/inexpensive RC circuit (no programming required).
I believe for many train-related servo applications you don't need to mess with an Arduino and programming which is not in everyone's comfort zone. I believe there are some guys who will (perhaps reluctantly) solder/assemble a circuit before writing a program.
Just as there are many sample/example Arduino programs for servo control, there are many sample/example no-programmming-required electrical circuits for servo control. Best to first define the requirements (the WHAT) before proposing a solution (the HOW)...cart before the horse, measure twice cut once, etc.. 
Defining the scope of the problem is clearly the first thing to do, you couldn't be more correct! In my case, it was a dirt simple circuit to simply toggle between two pulse widths, the 555 was the perfect solution. In a way my upgrade was wireless, I use the Legacy remote to control it.
There's a lot you can do with the simple three-wire servos, and they're another item that's dirt cheap if you look. For less than $2/ea shipped, you can have this little guy complete with several styles of actuating arms.
Dan Padova posted: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.
The OP seems to want to control the servo via a hand held RC radio. If this is in fact the case I can steer him to exactly what he will need and not waste any money in the meantime. What's needed is radio, receiver and a BEC to regulate voltage down to 5 volts. Plug power to in side of BEC, plug out side of BEC to receiver, plug servo to any numbered channel port on receiver, hold bind button down on radio while turning power on to radio, continue to hold bind button on radio and radio will say binding in process. After a few seconds the radio will say binding process successful. Turn radio off then back on and you should be able to move the servo with one of the radio sticks. If you want to be able to adjust the speed at which the servo moves you will need to program the servo to the flaps channel on the radio then you can adjust how fast or slow the servo moves as well as how far the servo moves in each direction.
I didn't really consider the servo control it's self here, more the radio control. Controlling a servo with Arduino is so simple as to not really have been considered. ex: " myservo.write(value); " where myservo is the name of the servo you wish to control and value is the number of degrees of rotation you want it to turn to. If one only needs servo control, and doesn't mind cobbling a couple simple components together, then the 555 is probably the way to go, if you need to save every penny possible. However, given how intimidated many folks here seem to be about things as simple as LED lighting for passenger cars, I'd think a solution that requires no soldering of components might be appealing.
JGL
Dan Padova: I wrote the Sept. CTT article on servos. I have written over a dozen articles on servos for model railroads in five magazines. I described a very simple RC control system for servos in the August 2012 SERVO magazine. There was a comprehensive article on servos for model railroad applications in the May 2014 SERVO magazine. The December Lionel Collectors Club magazine has one of my latest efforts, a servo animated passenger station. Let me know if I can help.
Sadly, most of us don't have access to issues of various magazines to check out the previous works.
I was reading this just tonight...
http://www.trainelectronics.co...Player-MP3/index.htm
This guy also has a fantastic tutorial for smoke using an E-cigarette.
He's doing a lot of neat stuff, nice site!
rogerpete posted:I was reading this just tonight...
http://www.trainelectronics.co...Player-MP3/index.htm
This guy also has a fantastic tutorial for smoke using an E-cigarette.
Yes, Dave has some good stuff on his website and YouTube channel. I was just getting ready to mention that.
I also second using a micro controller. If you are going to use one of the smaller Arduino boards like the nano. Just note they are run on 3.3v and not 5v. I think servos can run on 3.3v, but make sure.
Also, if you want remote control you can always use one of these https://www.adafruit.com/products/389 and Adafruit has written a library (see link at the bottom of the product page) for the arduino to decode the button presses and Dave has used these remotes in some of his projects. This way you can run multiple servos. You can attach an LCD to the arduino to see what commands are received. You may want to use an Arduino Uno or Mega depending on how many you want to control.
I recommend starting small using examples in the arduino software and expand your system as you succeed in order to learn the code. Also, there are many websites, YouTube channels, and more that will help along the way. Here are some resources:
Jeremy Blum's Arduino Tutorials (YouTube)
There was also articles in the lastest edition of Model Railroad Hobbyist Magazine (free on-line subscription) about Arduino and Model Railroading. There was one on servos and they have example code for download.
I love Arduino and have several projects I'm working on for model railroading.
Hope this helps.
Chris
Sorry to be so long in getting back to this topic. It seems that the Spectrum transmitter and some extra receivers, the small orange type, that I have on hand may work. If I use a servo on an animated project, like a freight car, and have a power source for the receiver, I can use the transmitter to control it.
One of the members on Large Scale Central posted what seems to be an answer even I can understand. He wrote the following; "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".
Here is a sample of what I have been doing using servos that I gutted the PCB from. It's simply a servo motor less the PCB. I control the servo motor using an inexpensive Chinese receiver and transmitter. The only down side in the case of this unloading car is that I cannot keep my finger on either the unload or the button that allows the cradle to come to rest, lest I damage the motor. The good part of these cheap R/C set-ups is that you have a choice of momentary or latched transmission.
Dan Padova posted:Sorry to be so long in getting back to this topic. It seems that the Spectrum transmitter and some extra receivers, the small orange type, that I have on hand may work. If I use a servo on an animated project, like a freight car, and have a power source for the receiver, I can use the transmitter to control it.
One of the members on Large Scale Central posted what seems to be an answer even I can understand. He wrote the following; "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".
Just so I understand, you found a solution to your wireless radio-control servo question - a Spektrum transmitter and Orange servo receivers. It was not clear to me if the requirement was something integrated with an existing train remote control system (TMCC/Legacy, DCS, DCC, etc.) or if a stand-alone/independent control system was acceptable.
Dan Padova posted:Here is a sample of what I have been doing using servos that I gutted the PCB from. It's simply a servo motor less the PCB. I control the servo motor using an inexpensive Chinese receiver and transmitter. The only down side in the case of this unloading car is that I cannot keep my finger on either the unload or the button that allows the cradle to come to rest, lest I damage the motor. The good part of these cheap R/C set-ups is that you have a choice of momentary or latched transmission.
And that this sample is a separate discussion from the above radio control servo issue. That is, if you gutted the PCB from the servo you are really left with just a small DC gearmotor; it's no longer a servo per se. So without the angle/position feedback of a servo, you are left with basic "on/off" or "fwd/rev" DC gearmotor control. That is, I see only 2 wires going to the mechanism which are going directly to the 2-terminals on the DC motor within the servo case?
Then, by "inexpensive Chinese receiver and transmitter" you are referring to something like these? These offer low-cost simple on/off (e.g., forward/reverse or dump/reset log cradle) momentary or latched radio control.
So as I see it, there are possibly 2 outstanding issues.
1. If you are asking about integrating the activation with an existing train control system so that you don't have multiple radio-control remotes to fuss with.
2. If we ignore the radio-control issue and clarify your comment about damaging the DC gearmotor. Are you saying you did not remove the angle-limiting mechanical stops (e.g., the feedback potentiometer) within the servo case and you are concerned about the motor stalling (and drawing large current) when it reaches the end-of-rotation in each direction?
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