Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: jonas on December 24, 2005, 04:31:26 PM

Title: r\c control \computer control
Post by: jonas on December 24, 2005, 04:31:26 PM
First of all thanks for all the info on the main site very usefull.  Second of all a question, how could I make a robot with r\c control, then have its main program run off the computer. 

Like the computer tells it to go forward it starts going forward then the robot send back theres and obsticle then the computer tell what to do next.  I'm I making since?  I want a romote controll unit hooked up to a computer and a joystick.

Just let me know if I'm not making since and I'll say it different!
Title: Re: r\c control \computer control
Post by: Admin on December 27, 2005, 08:51:28 AM
Hmmm several ways to go about this . . .

1) Get an R/C reciever and remote. Open up the remote, hack it, and attach it to a computer serial port. Attach the reciever to a microcontroller (or just servos) on the robot. When the robot recieves a certain signal, it can do a preprogrammed motion.

2) Buy a wireless robot communication module. They sell a few online, but I have never personally used any. Probably the easiest but most expensive method.

3) If you really do not need wireless, just control it by serial port connected between both your computer and microcontroller.

4) If you really do not need a computer for computation expensive calculations, get a regular R/C remote control. Hook up a reciever to your microcontroller. When you send a certain signal to the reciever, the microcontroller can interpret it however you want - like a complex set of actions (great for remote controlled walking robots).

Sorry I couldnt go into more detail. All of these methods are a little complex, so just look into them for awhile and see what you can come up with.
Title: Re: r\c control \computer control
Post by: jonas on December 30, 2005, 05:19:37 PM
Thanks step 1 would be how I would go.  would it be possible to take the r/c control box remove the joystick and attach a game pad to it(for more buttons)?  Then would I need to replace the other joystick place with the serial connection, or were do I attach it.

the reason I go with option 1 is I have a r/c car that don't work, but the motors work and the remote.
Thanks for help.
Title: Re: r\c control \computer control
Post by: Admin on January 03, 2006, 12:10:03 PM
Hmmmm what you are asking for requires a lot of hacking and is somewhat complicated so I cannot really go into much detail. I will just tell you the general method and you can investigate further.

It is possible to take the R/C controller and basically attach a game pad to it. Unfortunately you are not allowed any more buttons than the R/C remote already has.

Open up the R/C controller, and inside you will notice that attached to each 'stick' is a little potentiometer (variable resistor). This potentiometer sends a signal to some other circuitry. To control your R/C controller, you either need to control the potentiometer, or mimic the signal sent with the potentiometer. If you want to control that signal through a computer, you would need to hack up some type of interface.

There are several options you have.

1) Break open the R/C controller. Attach servos ( ) to the potentiometers. Find and download some software online that lets you control servos with your computer (example - ).

2) Send commands to a microcontroller ( ) with your computer. Have the microcontroller then send the proper signals to the R/C controller circuit (which will then be sent to your robot).

Note that you can attach your joystick to your computer, and use a program that reads what your joystick is doing.

Just remember, keeping things super affordable also makes things much harder. Good luck!
Title: Re: r\c control \computer control
Post by: dunk on January 29, 2006, 08:05:26 PM
i reacently completed a similar project Jonas.
i wanted to be able to controll a bot over the internet. (i realy must get round to documebting the ptoject.)
the bit you will be interested in is the controll link.

most micro controllers have a UART which is very similar to your PC's serial port.
with a small bit of circuitry (a MAX232 and a few capacitors) you can connect the UART to the serial port.
then in hyper terminal (comes free with windows) you can type charicters to be received by the micro. (and vice versa if you require.)
switch on and off pins depending on what tou type.

once you have that working you can replace the wire link with a transmitter and receiver fairly cheaply. these are not the cheepest but you will get the idea from their data sheet:
for one way communication you will only need a TX and a RX.
for 2 way you will want a pair of receivers.

hope this helps. the tough bit is getting the UART on your micro working.
the wirless bit is easy enough after that.

Title: Re: r\c control \computer control
Post by: jonas on January 29, 2006, 10:30:02 PM
I know that you can use an Oscillator to send the signal and I know how to do that but I will have to find out how to make a good receiver.

Thanx,  I would be interested in finding out about your project.
Title: Re: r\c control \computer control
Post by: dunk on February 01, 2006, 04:04:15 PM
yea, i spent a long time trying to make my own transmitter and receivers. they kind of worked for low data transmision rates.
eventually i just bit the bullet and bought one. they are quite cheap, simpler, smaller and *far* more reliable.

you need a transmitter and receiver on the same frequency. simplest if you stick to the same manufactorer for both.
for an example of a pair that will do the job go here:
and search for this transmitter: fm-rtfq
and this receiver: fm-rrfq
(i don't think farnell's site works if i link straight to the product.)

there are a few different manufactorers making units like this.
they contain all the electronics for the transmitting and receiving. you just need to supply 5V and connect a small length of wire for on arial.

i used a tranceiver from these guys in my project: ( supply these as well i think) because i wanted 2 way comunications. (i wanted the bot to be able to give feedback on batery level, temperature, etc.)
a tranceiver contains a transmitter *and* a receiver in the same module.
i can thourghly recoment those modules that i used if you also need 2 way comms but if you only want 1 way there are far cheeper companys providing similar.

happy buiding!

Title: Re: r\c control \computer control
Post by: Admin on May 02, 2006, 10:49:52 AM
Just found this usb radio telemetry module thingy:

and this cheaper one
Title: Re: r\c control \computer control
Post by: Kohanbash on August 06, 2006, 01:41:16 PM
If your familiar with Linux and basic programming it is fairly simple to get a generic wireless controller(for PlayStation etc..) to work. When it gets plugged into Linux you can open up the dev file and see the bit pattern. using this it is easy to program based on the bit patterns. i like PlayStation remotes due to having a lot of buttons, 2 analog joysticks, and the digital pad.
Title: Re: r\c control \computer control
Post by: dunk on August 06, 2006, 02:44:00 PM
hi sdk32285,
very interesting.
i can see that being very usefull to anyone who wants to feed information into a computer with a USB port.
usefull for sensor input and stuff.

what about actually controlling devices this way? i'm currently working on a USB motor controller for my latest bot and it hadn't really occurred to me there might be a product out there this easily hackable.
do any of these controllers have LEDs you can switch on/off from the PC? i know some of the non wirless ones have those vibrating packs right? that means it's possible to controll at least one device using them.

i'll probably keep working on my own controller but still interesting to hear different ways of doing things.

Title: Re: r\c control \computer control
Post by: Kohanbash on August 06, 2006, 05:43:23 PM
Hi I usually attach serial motor controllers and other devices to the computer. For other devices you can either use multiple pins on the serial/parallel lines or in my case with a pc104 I have an I/O card and a relay board that can be used.
With the USB controller you just send your signal using the RX pin. If you don't need feedback you can theoretically mod the TX line to also provide output to a controller.
The LED's on the controller are usually not able to be used for output. they just act to modify the bit stream(IE pressing Select flips the MSB) I have never used the rumble as an output but that's an interesting idea.

(Also a lot of the wireless ones also have the rumble pack)
Title: Re: r\c control \computer control
Post by: Admin on November 28, 2006, 09:07:36 AM
recently found this . . .

apparently you can hack the trainer signal connection on the back of the remote:

connection diagram

some info stuff

download the zip on this one for good info

here's the wireless UART.  you might find something that's lower frequency. I don't know.
Title: Re: r\c control \computer control
Post by: HDL_CinC_Dragon on December 19, 2008, 09:22:29 PM
@admins last post:
welwyn was moved thus those links dont work properly website with sub folders gives me a 404 but the main site I can still get to

I just realized I revived a very very dead post... sorry :(
Title: Re: r\c control \computer control
Post by: tristantech on December 30, 2008, 09:06:37 PM
You might find this article useful:
Title: Re: r\c control \computer control
Post by: Joesavage1 on January 21, 2009, 01:14:31 AM
can you not make an R/C robot without a microcontroller? i thought u just needed to plug servo's and batterys into revciver?!


Title: Re: r\c control \computer control
Post by: HDL_CinC_Dragon on January 21, 2009, 08:43:47 PM
can you not make an R/C robot without a microcontroller? i thought u just needed to plug servo's and batterys into revciver?!


pretty much