Remote Control Explanation

[Michael]

Remote Control is something new to me and I always like to know how things works. Could someone please explain how RC works at an electrical level? Taking the Spektrum DX5e for example, what do you get for your 5 channels, is it the 4 movements on the 2 joysticks plus a switch for the 5th channel? How does this relate to the voltage levels on the receiver electrically, that is what happens at the receiver output when the joystick is moved up and down.

Thanks

Michael

 

[Steve]

Hi Michael ,

Starting point on here would be -

Tony Walsham
Johnsaintjim
Doug

I am sure there are many more but these three would be able to help you.

 

[chris m01]

Apologies if this sounds picky but I think you should head this thread radio control. Remote control doesn't necessarily mean wireless whereas radio control does mean - well by using radio waves.

 

[coyote97]

Hi Michael,

im using a spectrum RC, so if there are any further questions, u can PM me everytime.


The basics:

first:
with RC there is one mainthing to know:
the current state of technics is 2,4 GHz twinchannel.

The "normal" RCs (27, 35, 40 MHz singlechannel) are in need of some free space arround the model, and there are many bugs with modelrailroading due to the landscape or nearby housewalls, fences and things.

second:
with conventional track power, your control unit is fixed and gives the power to the tracks. The drive-control is in your hands so to speak.
For RC u need to have the controler onboard. Normal car-or truck controlers work fine, special products for RR offer special features. But they are too expensive in my eyes.
DONT use cheap 1-3 Ampere controlers, they wont last...

third:
the RC receiver needs a voltage with about 4,8 till 6 V. simply use a BEC-controler, that gives out the needed voltage to the receiver and so no separate supply for the receiver is needed...its taken out of the big drive supply.

fourth:
ME, i use 12V lead-accus by now, but they seem to be overcome by LiPo-accus.
LiPo´s are told to be a bit dangerous with charging and under heavy power, but they are extremely powerful regarding the weight.
DONT use cheap NiMH Accus! They dont last and cant stand the current needed for locos!
Thats the advantage of lead-accus: they dont have the big capacity, but are good to handle, stable and not dangerous in any way: i use panasonic-fleece-ventile--blablabla--the hell accus that can be used in every position.

fifth:
there is a better way to controll with standard RC than the sticks. I use a jamara-RC that provides 3 turning-knobs and are furthermore programmable.
That makes it possible to controll 3 locos from one RC station at the same time.
Jamara has receivers that allow tho bend on the station EACH seperatly. U just have to put the "drive" channel in each loco to another RC channel and u can controll 3 locos like on digital: completely independent.
Only thing a bit difficult is that the timewindow to switch them on is only 3 seconds. there u have to switch on the station and the locos. after that, no new receiver is allowed.
The jamara has an inbuilt failsave that stops the loco. If there is any rubbish in the air, the locos dont dance arround silly, they just stop.

Regularly, i had to take them back to control by turning the drive channel to "0". wait a second or two and the it starts over.


sixth:
with taking the drive away from the stick, u can use them for functions.
While the spectrum DID work with a Conrad-Multi-switch, the Jamara DIDNT....***grumble*** but there ARE multiswitches that allow to use 2 RC channels for 7-16 functions. So u can use one stick for the functions of loco 1 and 1 stick for the functions of loco 2. Like this, u can even whistle and bell and uncouple completely independent.


driving doubleheaded:
The jamara makes it possible to drive doubleheaded. but not by controling two locos parallel the same!
U control EACH loco seperatly..2 of the 3 turning knobs are in "fingerwide" neighbourhood.

Thats great fun!

switching and shunting with two locos, coupling and then doubleheading. U have to have a fine feeling for the control to see what loco needs more or less power. But no problem to push a train with a fast 4-4-0 up an incline with a slow shay!!!


I added a supply-wire to each loco, just leave me a note when u are interested. Allows to take power from a accu-car, in case the accu is off on line.....


Frank

 

[Doug]

Remote Control is something new to me and I always like to know how things works. Could someone please explain how RC works at an electrical level? Taking the Spektrum DX5e for example, what do you get for your 5 channels, is it the 4 movements on the 2 joysticks plus a switch for the 5th channel? How does this relate to the voltage levels on the receiver electrically, that is what happens at the receiver output when the joystick is moved up and down.

Thanks

Michael

Each Tx has a different way of providing the channels, some use sticks, some rotary knobs, some of the smaller ones use button to press. The best way to find out is to find someone with a set and try things out. A model aeroplane shop is also a good place to try things out.

At the electronic level - its mainly smoke and mirrors. Don't worry about it, you just have to understand that moving something on the Tx results in a servo moving or an electronic controller changes the speed/direction of the model. You just need to find the Tx that suits you.

In a recent 16mm Assoc magazine there was an article on how the 2.4GHz systems work - about 4 sides of A4! Servos uses a fairly stand pulse technique to control their position.

 

[Del Tapparo]

Remote Control is something new to me and I always like to know how things works. Could someone please explain how RC works at an electrical level? Taking the Spektrum DX5e for example, what do you get for your 5 channels, is it the 4 movements on the 2 joysticks plus a switch for the 5th channel? How does this relate to the voltage levels on the receiver electrically, that is what happens at the receiver output when the joystick is moved up and down.

Thanks

Michael

In simple terms, this is how the electronics work: The receiver receives a string of pulses from the transmitter via radio link; one pulse for each channel. The width of the pulse is directly proportional to the position of the stick on the transmitter. Hence a narrow pulse at one extreme, fat pulse at the other. The receiver then steers each channel's pulse to the a proper channel connector. The ESC (Electronic Speed Control) looks at the channel and measures the width of the pulse, and therefore knows the position of the stick.

 

[Michael]

Thanks for all the replies and advice and Del thanks for your explanation, I understand it better now.

My ESP arrives soon but I haven't chosen a transmitter yet. I'm surprised that there aren't any specifically for rail rather than the joystick ones.

and yes I love the warning messages for the Li-Poly batteries.


Michael

 

[gregh]

Remote Control is something new to me and I always like to know how things works. Could someone please explain how RC works at an electrical level? Taking the Spektrum DX5e for example, what do you get for your 5 channels, is it the 4 movements on the 2 joysticks plus a switch for the 5th channel? How does this relate to the voltage levels on the receiver electrically, that is what happens at the receiver output when the joystick is moved up and down.
Thanks
Michael

Del Tapparo gave a really good explanation, but maybe I can add a bit.

Here’s a pic of my 2.4 GHz transmitter. These are bog-standard model plane controllers and the names used are things like elevators, rudder and throttle. Forget all that.

You get 2 sticks that can each move up/down and left/right. That’s 4 channels you can control. Three of these sticks are spring loaded so they sit in the centre when not pushed up/down/left/right. The 4th stick is the throttle and is NOT spring loaded – when you push it up part way and release it, it stays put. In the pic, it’s the right stick – you can see it in the zero speed position.
All these 4 controls are ‘proportional’. This just means that if the stick is halfway up the signal being received tells the servo or motor controller to ‘go to halfway’.
The usual ‘thing’ on the receiver output for planes is a servo motor. They just plug into the ‘channel’ outputs of the receiver.
See pic.

It is just a very low geared motor that has a rotation of only 90 degrees. If you move a stick from its centre to top position, then the motor moves through 45 degs in one direction. Pulling the stick down from centre, moves it through 45 deg in the opposite direction.

You can buy electronic speed controllers (ESC) that plug into the throttle channel output on the receiver. They just put out a voltage that is proportional to the throttle stick position. They are often rated at 20 amps or more which is more than enough for our trains. So if you push the throttle stick up 30% of the way, you’ll get 30% of battery volts on you motor. I don't see why people would want knobs to twiddle as a throttle. Sticks are really simple and easy to use.