PC to RC interface

[Snef73]

Has anyone successfully built and used a pc to rc interface? such as the one described on this page:

http://www.welwyn.demon.co.uk/PC_RC/PC_to_RC.htm

I will order the pic chip from him and build it. I will try to code a program that will hover a piccolo helicopter with little or no external help.

Are there any other sources for pc to rc interfaces?

Thanks

[jrb]

Electronic projects can be great fun; I’ve down my fare share that consumed a couple of buck in parts and a few hours in time.

Checkout this thread, the serial port (or parallel) isn’t the best port to use: http://www.rcgroups.com/forums/showthread.php?threadid=97472

[Ollie]

The trouble with what you are trying to do is that there is a noise input to the control loop that the program can't take account of unless there is information feed back to the program on the actual position of the aircraft. The noise input takes the form of aircraft position change due to wind gusts and other outside influences that the control loop, including the program, has no information about and thus can't correct. The position error will accumulate and control will be lost. Manual intervention by a pilot exercising visual feedback of aircraft position will be required to prevent aircraft loss or crash.

[Snef73]

For now, I am concentrating on indoor flights only.

The problem is that I cant find a schematic.

[propfan]

As Ollie says you need some way to tell exactly what the helicopter's doing. Suppose the trim is off a little. The heli will start drifting from level - but the PC will still think it's just fine, even after it crashes.

http://autopilot.sourceforge.net/ - They have schematics but it's way too big and complicated to fit into an indoor heli. For just hovering you *might* get away with simple tilt sensors like the ADXL2xx accelerometers they're using.

[steve lewin]

That circuit by Ken Hewitt is the only one I've seen for that purpose. It's not a very practical thing to do in the real world as the others have pointed out. I think you'll need a good stock of spares for your Piccolo because you'll be repairing it after each "flight".

If you're really interested I suggest you start with something easier to control like a car. When you have worked out a program that can successfully control that then you can think about all the extra problems of control in 3 dimensions.

What you're trying to do is basically more similar to advanced robotics than to normal R/C. You might get a few ideas from some of the robotics sites.

Good luck

Steve

[FLYBOY2]

I've been looking for the same thing, but I need more channels than what the circuit designed by Ken Hewitt will supprt, and I would much rather use PCM. If anyone has any leads, please let me know. I am planning on using 2 Futaba 9c's. I need 17 channels.

[Snef73]

17 channels? What are you going to use it for?

[Thomas B]

Ahh.....the siren call of pre-programmed flight. In the middle ages, it was the desire to convert lead to gold. This century, it was cold fusion and pre-programmed flight.

As Oliie mentioned, auto flight MUST have feedback into the control loop to allow for outside influences and trim issues. This is why they make autopilots and similar devices.

Even a small indoor helicopter must have this, and the control needs vary slightly as the model hovers at different heights, wanders around in the rotor downwash/uplift as the air reflects from the ground, etc.

[Ollie]

Originally posted by Snef73
The problem is that I cant find a schematic.

The problem is that you need a workable system concept before you will know what kind of schematic to look for.

You will need gyro input or GPS input or some other kind of positional reference information input to your airborne circuitry.

"There are none so deaf as those who will not hear."

[FLYBOY2]

The 17 channels will be used to control 5 charactors in a childrens play. All 5 of the charactors will have there servo controled mouths tied to there audio channel so the mouths will sinc. Two channels each will control there eyes. One of the charactors will also have its arms controled by RC.

[FLYBOY2]

Snef,
Check out this Co. I think they are working on the same application as you are thinking about.

http://www.rotomotion.com/prd_REV2.4.5DOFK.html

[Thomas B]

I have done a good bit of servo controlled animation using this program and the $45 Mini Serial Servo Controller board:

http://www.mister-computer.com/MCSSCv12/index.htm

A great little program for controling servos via the serial connection on your computer. Add a wireless serial relay of some kind and you no longer need a 17 channel radio.

Does not support servo movement slaved to audio input, but everything else is there.

Pricing:

http://www.mister-computer.com/Pricing/index.htm

The Mini SSC interface boards require 5v and 12v DC power. One end of the board takes a serial signal from your computer. The other end of the board has pins for 8 standard servo connections. Boards can be added to control more than 8 channels. I have a couple of projects running 30-32 channels of input and upwards of 50 servos.

[Thomas B]

And here is a low cost wireless serial interface that would provide wireless direct AND recorded playback of servo motion direct from your computer, using the software and hardware mentioned above:

http://www.abacom-tech.com/catalog/ARX8_ATX8user.pdf

This company has a number of attractive wireless solutions for this type of need.