Controlling your R/C transmitter from a PC using an Arduino

Question

Hello,

Here is a project i am trying to build:

https://www.min.at/prinz/?x=entry:entry130721-182227

The problem is that i understand Arduino scripting only at a very basic level.

My question is:

Should i upload the protocol code with all the hex addresses in it **as is** to the Arduino or is it only a protocol general description, from which one is supposed to build the Arduino code itself?

Since i only understand simple Arduino scripts and know almost nothing about hex addresses (besides the way they look)...is it complicated to build the Arduino code itself, from that protocol description? How should that be done?

Thanks.

balearicdynamics · Answer

Roi, it's not the first time I find - especially with low cost "hobby" servos defective ones. Their cost is so low that it is not the worth to ask for replacing them So, I think that if you try with other servos and all works fine we can consider the problem solved. BTW it's nice anyway if you spend few time to make some shooting to your project and publish them, maybe in an article in the Arduino section, why not? Cheers. Enrico

balearicdynamics · Answer

Hello as this is shown as the code (I took a fast look to the link you mentioned) I suppose that this is the code that should be uploaded "as-is". Obviously I expect that it works just with the specific hardware and the exact connections, wires, circuitry etc as shown in the article. Anyway this will be a good starting point to see what happens then you can get some helpful hints here (here and there ) to change the stuff as well to fit you specific needs (best if you explain exactly what differs in your project from this).

Enrico

balearicdynamics · Answer

SORRY !!!

It was my mistake as I have not read in detail. Veeery sorry Then, it is an error of the author too as he put in a code source box (with comments in c-style) what is probably an output from the serial port.

This was the bad news. instead the good news is that this project uses the Firmata protocol. This means that there is no code to write at all on the arduino. The firmata protocol is a source that is already present in the IDE and that should simply uplaoded to your Arduino. This convert the Arduino as a microcontroller able to receive commands and execute them with a specific protocol, usually connecting it to the serial. This means that you will use it as a machine and the only code needed are the commands that you send, in this case from the Pc.

Take a look to the firmata protocol in arduino.cc, I have used it in one of my projects to control hardware from a Java application on the Mac. If you have difficult to follow the instruction uploading the protocol on the Arduino let me know, anyway it is just one of the examples you can simply upload to your board.

I apologize for this mistake.

Enrico

balearicdynamics · Answer

Roi, as you can see in the following image, there are several kind of Firmata "versions" you can upload to your Arduino board. Depending on the one you choose you can use the same protocol to manage analog signals instead of PWM and so on. here are two links related to the protocol: Firmata Messages : Outgoing | Devartia Firmata Messages : Incoming | Devartia I suggest to try to upload the StandardFirmata version, sure excluding the Ethernet, Yun and Analog, Servo firmata as they are specific for features that you don't need. Then try it the communication works fine with the PC. Enrico

balearicdynamics · Answer

I wrote : I suggest to try to upload the StandardFirmata versio nI This will be the first try I'll do. Continuing to exclude something very specific like Ethernet and Yun firmata version that will work with dedicated protocols, the fast tries you can do is to replace the standard firmata with the other version, maybe - as you have to move servos - from Firmata servo. Then if this continue to not working try the other remaining versions. At least we can exclude, if none won't work again, that it is not the firmata version you are using. If things goes well we are happy with minimum effort else we try to see in depth how this PC program work and what expect to receive from the Arduino board with firmata installed. Enrico

clem57 · Answer

Did you do a pull request at https://github.com/firmata/arduino/blob/master/examples/StandardFirmata/StandardFirmata.ino If not you may have gotten bad code. Clem

balearicdynamics · Answer

Mmmmhhhh. I have not saw the sources of the PC side but I am tempted to think that this depends on the stability of the Arduino - supposing - PWM control. As in the article it is mentioned that they have used a modified version of the standard firmata, maybe a program error. But should be checked in depth what these changes do. As far as I know, Arduino is not the ultimate solution in the world, but I have used firmata to control servos and the response (with a modified Firmata to adapt to my needs) was almost good. But these are only suppositions, at this point a serious analysis of the sources is needed Enrico

balearicdynamics · Answer

Maybe you can show how the problem occur? When the servo is stopped, while running, in what position etc. It is more important than what you think Some examples: TiltPan Micro Camera Arduino Shield is working now This is under exclusive Arduino control. It is a stop motion but I grant that position was almost stable and sure not vibrating TiltPan Software essentials ... and this is the Arduino software The following video instead is the version controlled by a MacBook PRO. Same architecture principle, arduino with modified firmata, custom controller board for servos (the shield mentioned in the previous articles) and a Java application on the Mac

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roineust · Answer

Actually i think it is a good quality Savox servo, if you are aware of this brand by a chance - but one that i'v put through rigorous tasks, so maybe that is the reason for its flawed reactions. It is supposed to be a better brand than average, at least it appears so from the price of that servo. Regarding the project - i hope that in the very near future i will be able to share its details.

balearicdynamics · Answer

Thank you Roi, in some projects I have also planned to use servos and I buy usually low cost ones to make prototypes / testing but then it is a good indication when the project become a minimum commercial or at least should be used for something reliable. Enrico

balearicdynamics · Answer

Clem, AFAIK he tried to upload the code of the article, the Firmata version is included in the Ide. Anyway if there is a problem I have a version that will work for sure because I have used for the first tilt-pan hardware control from my Mac and a java application. Enrico

roineust · Answer

Thanks Enrico,

My project almost differs at nothing from the project description - even the RC TX i'm using is the same model.

That is good news for me, your estimation that this is a code that is ready for upload as is.

balearicdynamics · Answer

This project sounds interesting Roi, so it will be interesting if you document your setup so other users can see what happens. Then if some problem arise let us know Enrico

roineust · Answer

Enrico,

When trying to upload the code to Arduino i get the following error messages:

Arduino: 1.6.2 (Windows 8.1), Board: "Arduino Uno"

RC_to_Arduino.ino:2:1: error: 'Send' does not name a type

RC_to_Arduino.ino:108:44: error: expected unqualified-id before '>' token

RC_to_Arduino.ino:108:58: error: expected unqualified-id before numeric constant

RC_to_Arduino.ino:116:44: error: expected unqualified-id before '>' token

RC_to_Arduino.ino:116:58: error: expected unqualified-id before numeric constant

Do you have any idea why this happens?

As well, in my previous computer, the Arduino IDE used to mark-up the lines in which there is an error and now, it only shows the error messages at the bottom of the window, do you know how can i make it mark-up the error lines? I can't find such an option in the menu..

Thanks.

Controlling your R/C transmitter from a PC using an Arduino

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