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Old Jan 01, 2006, 07:02 PM
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pc-to-rc-interface

Hi,

Anyone have any experience in building this?

http://www.welwyn.demon.co.uk/PC_RC/PC_to_RC.htm
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Old Jan 02, 2006, 05:34 AM
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To be honest that would appear a tad dated now, as USB RC-PC interfaces that emulate a standard "windows joystick" are more common.

Two things to watch with that CCt:
1) Unless the VB program overcomes the issue, under XP there is no direct port mapping, so access to LPT port may result in communication errors (this is why people use applications like PPJoy)
2) The project doesn't include the HEX code for the PIC, so bear in mind that you have to purchase a pre programmed PIC at 6 ($11 USD)

Just my 2c worth... if you go ahead and purchase the PIC and build it, let us all know how it works and what you can do with it
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Old Jan 02, 2006, 06:55 AM
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Quote:
Originally Posted by Malc C
To be honest that would appear a tad dated now, as USB RC-PC interfaces that emulate a standard "windows joystick" are more common.
I've never seen a USB interface with a program to allow the PC to drive the Tx. Generally PCs don't send commands to joysticks. Do you know of such a program/interface, it could be interesting ?

I've only ever controlled a Tx years ago by driving a serial port directly and that's considerably trickier to do post-Win98.

Steve
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Old Jan 02, 2006, 04:02 PM
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Malc, Im looking for a solution to allow a pc to drive the transmitter not a joystick interface.

I have purchased the pic and completed the circuit yesterday. The reason Im posting is because I can't get it working. I am using windows xp, could this be my problem? Im sure that the circuit is put together correctly. I have checked and rechecked all connections. Im using a futaba T4YF 4ch transmitter. It has a 9pin square connector that looks like this:

(futaba 9 pin)
------------
| 3 2 1 |
| 6 5 4 |
------------

I connected the output from the circuit to input pin 6 and the ground to pin 2. According to this site http://www.model-gadgets.com/info/infopage/infopage.htm this is the correct way to connect it to this transmitter. I also opened it up to verify.

When I try to start up his sample visual basic program I get an error saying that the interface is not connected. If I flip the trainer switch on my radio one of my channels(the throttle) goes at full speed and the servos go through a glitching pattern.

Just today I found a link to an article in Servo Magazine that does a very similar project. Here: http://www.servomagazine.com/preview.php?issue=5
I was able to find a research paper that the author wrote that includes the schematic. Found here: http://prism2.mem.drexel.edu/~paul/p...enIcar2005.pdf
The two designs look very similar. The .hex files are even provided for the project on Servo's site: http://www.servomagazine.com/downloads.php?5 I tired running the software provided and it doesnt give me the error message. but it still fails to control the transmitter.

Ive tried contacting the seller but he hasnt responded yet. Anyone have any ideas?
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Old Jan 02, 2006, 04:15 PM
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Quote:
Originally Posted by slipstick
I've never seen a USB interface with a program to allow the PC to drive the Tx. Generally PCs don't send commands to joysticks.
Steve
I'm guessing that what is needed here is an interface that connects to the buddy box socket....so the pc replaces the joystick interface on the tx, and outputs to the model via the rf stages.....otherwise I've lost the plot completely....
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Old Jan 02, 2006, 04:16 PM
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Prankster, I imagine Win XP is your problem. It will not allow you to directly control the parallel port, which I believe is what Ken's program is trying to do. If you can find an old PC with Win 98 on it will probably work.

Chippie, I think that's what is required too. The problem with Win XP is not the interface itself but writing a program to control the parallel port in the way required i.e. where the timing of all signals is controlled by the PC.

Steve
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Last edited by slipstick; Jan 02, 2006 at 04:23 PM.
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Old Jan 02, 2006, 05:40 PM
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Quote:
Originally Posted by Chippie
I'm guessing that what is needed here is an interface that connects to the buddy box socket....so the pc replaces the joystick interface on the tx, and outputs to the model via the rf stages.....otherwise I've lost the plot completely....
OK I've re-read the details on Kens website

Quote:
There have been a lot of people asking how to connect a PC to an RC transmitter via the buddy box socket so that they could have their PC control some sort off RC vehicle.
So in esssance, the interface works in reverse of a game simulator, in that the data from the PC is sent to the transmitter, via the interface which generates a PPM signal and feeds it to the transmitter to send it via RF to a receiver fitted to an RC model.

I thought the item was some form of interface for use with a sim or something. The better alternative if you simply want to control servos from the PC then a serial servo controller like this one is more practical, unless the model is going to be some distance away from the PC.

Steve is also spot on that XP is the more probable cause of your communications problem, As I stated in my other post, under XP you can not directly access the ports in the same way as you can under Win95, 98, and ME. My guess is Ken originally wrote the VB program before XP was released (a hint might be in the sentance "A windows demo program written in Visual Basic 3.0" which I think is an old version as I think the current version of visual Basic is 6) - It might therefore be worth sending Ken an e-mail to see if he can resolve the issue.. other than that it might be worth looking for a 3rd party "driver" that will give the current version software port access.
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Old Jan 02, 2006, 07:53 PM
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Thanks for the help Malc and slip! Im going to install win98 on an old system and try that, Ill let you know how it turns out.
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Old Jan 02, 2006, 10:03 PM
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WinXP was the problem! I switched over to a box running 98 and it works great!
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Old Jan 03, 2006, 01:44 AM
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It seems that the Win98 version 's driver can't access the kernel mode of WinXP.
But it is very interesting with PC-to-RC interface. That will have a lot of application. If we record the fly actions (ppm signal), and re-play it through PC-to-RC interface in real situation with a pre-specified height (that prevent from crash easily), and do some maneuver by pre-recorded fly. That would be a challenge. because the status of motor, battery, and the wind speed is different each time, that will result in un-predictable flying situation(very dangerous, keep distance from it). But just for fun.
:P
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Old Jan 03, 2006, 05:02 AM
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Glad to hear you have found a resolution for the device... I would probably stick to cars or boats for experiments... flying a helicopter through the transmitter is hard enough.. doing it via commands from a PC could be tricky
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Old Jan 03, 2006, 05:21 AM
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but I lack of knowledge about the electronics and ICs.
If the product is come out, I would buy one.
If the product is for Linux OS embbed, and is open for using its SDK to control the radio controller and get the status from the RC(ex: height, air speed, GPS location, camera video,and so forth) that would be very great! I can use GNU C/C++ to program the RC flying automatic control system with its SDK and extra componets for plugging on RC fuselage.

just some fun idea!! It is a bit like UAV, but focus more on its API for people to use it and do some experiments.

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Old Jan 03, 2006, 05:00 PM
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My advice is to go the USB route and save yourself a lot of hassel.

Ready made units are available from;
http://www.milehighwings.com/usb_cables.htm

Or - if you are into electronics like me, you can build your own. You will need to be able to program a 16C745 pic and build a simple circuit. If you do not have a pic programmer you can buy a ready programmed pic from the circuit designer.

http://www.cattopasto.com follow the link on the left menu bar to 'FMSUSB'

Note that the hex code for the pic has been removed from the website. I can supply it to anyone that wants it. Just PM me.

I have used this interface with my Futaba FF7 super and Aerofly Pro. It emulates a pc joystick and it works really well. Very pleased with it.
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Old Jan 03, 2006, 05:27 PM
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Vince mate, looks like you too missed the plot

The original poster (Prankster) wants to send instructions from a PC to the transmitter and not the other way round.
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Old Jan 04, 2006, 06:32 PM
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Quote:
Originally Posted by Malc C
Vince mate, looks like you too missed the plot

The original poster (Prankster) wants to send instructions from a PC to the transmitter and not the other way round.
oopps sorry about that !
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