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-   -   Arduino Board and FRC Victors (http://www.chiefdelphi.com/forums/showthread.php?t=98727)

DavisC 09-12-2011 22:22

Arduino Board and FRC Victors
 
So, I made several attempts to use a potentiometer and the PWM outputs on a Arduino board that were connected to a Victor powered by the old FRC distribution board.

Has anyone else tried this? Mind sharing your code or some ideas?

Thanks
Davis

DonRotolo 09-12-2011 22:24

Re: Arduino Board and FRC Victors
 
A victor uses an R/C type PWM signal. A pulse of 1 mSec is full reverse, 2.0 mSec is full forward, 1.5 mSec is neutral. These pulses repeat at perhaps 200 Hz.

What kind of PWM pulses are you sending to the Victor?

nighterfighter 09-12-2011 22:53

Re: Arduino Board and FRC Victors
 
Hi-

I actually just recently used my Arduino to control both a Victor and a Jaguar, (Wired a potentiometer and had the Arduino scale the speed based on the pot value)

Try using the Servo library that comes with the Arduino.

Telling the pin to write the servo with a value of 90 will stop it, and > 90 is forward and < 90 is backwards.

If you want I can find the code I used.

Cory 10-12-2011 00:40

Re: Arduino Board and FRC Victors
 
Servo library is the way to go. Just finished a project using victors and the arduino. Banged our heads against the wall before figuring out arduino PWM output won't get it done. You need PPM output on the arduino, which the myservo.write() function will generate. Look up the servo example included with the arduino software.

DavisC 10-12-2011 10:42

Re: Arduino Board and FRC Victors
 
Thanks all. Yea I set it all up and tested it with the default "Servo Knob" example. Which worked great! I also added part to turn the 0 to 179 value into a -1 to 1 value and used the serial monitor to see the relative value.

Now I believe this is by far a stretch (considering the code is on the board), but has anyone successfully used a joystick with this? When using the computer, the only idea I would have is to somehow (i have no clue) send the joystick value to the board such as what the serial monitor does?

Also have you used the game pad shield to try and control it?

RoboMaster 10-12-2011 17:38

Re: Arduino Board and FRC Victors
 
I haven't, but Google it. I'm sure someone has and you can look at their resources. There's a massive community out there for Arduino.

Cory 10-12-2011 18:26

Re: Arduino Board and FRC Victors
 
Quote:

Originally Posted by DavisC (Post 1089939)
Thanks all. Yea I set it all up and tested it with the default "Servo Knob" example. Which worked great! I also added part to turn the 0 to 179 value into a -1 to 1 value and used the serial monitor to see the relative value.

Now I believe this is by far a stretch (considering the code is on the board), but has anyone successfully used a joystick with this? When using the computer, the only idea I would have is to somehow (i have no clue) send the joystick value to the board such as what the serial monitor does?

Also have you used the game pad shield to try and control it?

Sure. A joystick likely just has a potentiometer inside. Wire it to an analog input, then use the analogRead() function to get the value from the joystick. use the map() command to map the values of the joystick pot onto the range of values you are supplying the victor.

The Arduino website reference section will tell you how to setup all these commands.

RoboMaster 10-12-2011 21:47

Re: Arduino Board and FRC Victors
 
Quote:

Originally Posted by Cory (Post 1090025)
A joystick likely just has a potentiometer inside. Wire it to an analog input...

I think he meant a USB or other type of joystick connected to the computer or laptop, not a direct, wired connection.

You might be able to send it down with the serial connection, but you would have to get or write your own application for the computer side. Arduino's serial monitor can't help you with a joystick.

ajlapp 10-12-2011 23:14

Re: Arduino Board and FRC Victors
 
You can definitely hook up joysticks...we build complete robot control systems using only an Arduino.

Robot with Arduino control system

tsaksa 11-12-2011 12:42

Re: Arduino Board and FRC Victors
 
We did something like this as a side project this summer to build a wired controller for our robot for moving it around and testing without setting up a real drivers station. You can buy old game controllers at Goodwill or other locations for about $2. PS2 controllers are dirt cheap now. Have the students cut the connections to the existing PC board, and wire directly to the potentiometer. We used a standard 9 pin D connector which provided 5 volt power and ground into the controller to connect across the potentiometers. That left left enough extra connections to return the 4 analog values from the center tap on the potentiometers, and three additional connections that could be used to wire some buttons.

The students were very impressed with the idea of opening up an old controller and re-purposing it for a new function. The PS2 controller now just acts as a set of potentiometers and switches connected to the 9 pin connector. A little hot glue for strain relief, and reassembling the case, and the thing looks reasonably professional. The Arduino and a small battery to power it goes into another box that can be placed on the robot and also has four connectors for the PWM outputs. In use you can connect a standard serial cable between the controller and the arduino box since that has a 9 pin D connector as well. Just make sure you serial cable is straight through and not null modem.

I can post the code separately.

tsaksa 11-12-2011 13:15

Re: Arduino Board and FRC Victors
 
1 Attachment(s)
Ok, I have access to the code now. here it is

This is untested sample code supplied as is with no implied suitability for any actual application. The programming team is relatively new and still learning Java, so I wrote most of this just to get us started. We still need to test it a bit more and have the software team rewrite it at some point. But this should give you an idea of how to get started.

I had to convert the code to a .TXT file to get it to upload. Hopefully nothing got changed that would mangle the code. I think just changing the extension back, or cutting and pasting all or part of the code into the Arduino editor should allow you to use it. Our team does not have a lot of meetings left before build season, but if there is any interest I will ask for someone to take some pictures of the finished project.

DavisC 11-12-2011 15:31

Re: Arduino Board and FRC Victors
 
Thanks for the info.
@ajlapp - Was looking around on the site and looks interesting, do you have a document that explains how it is setup?

@tsaksa - That seems like an interesting project, I am definitely going to try that, and yea if you get a chance could you snap a pic.

Thanks,
Davis

Garrett.d.w 11-12-2011 17:45

Re: Arduino Board and FRC Victors
 
If you want to use a computer to send commands to the arduino then use Processing (arduino's computer based cousin). There is a library included in the software package that allows you to interface with the arduino though the usb serial connection.

If you want to control the whole setup remotely, you can use an xbee shield and radio to create a wireless serial connection between two arduinos.

Personally, I have used ps2 controllers as shown in this link (http://www.billporter.info/playstati...-library-v1-0/). It's much cleaner than soldering the connections to the potentiometers inside the controller, plus you can do some interesting things with the ruble feature, etc. There is also some canned code on that web page.

The web site also has a library for creating complex serial communication protocols (which comes in handy when you want to transmit more than one variable over a serial connection).

PM me and I can send you pictures of the project setup and code (if I can find it).

DavisC 11-12-2011 17:52

Re: Arduino Board and FRC Victors
 
Quote:

Originally Posted by Garrett.d.w (Post 1090225)
If you want to use a computer to send commands to the arduino then use Processing (arduino's computer based cousin). There is a library included in the software package that allows you to interface with the arduino though the usb serial connection.

If you want to control the whole setup remotely, you can use an xbee shield and radio to create a wireless serial connection between two arduinos.

Thanks, this is truly what I was looking for, I had thought of the xbee addition and that would work; I just didn't know a simple environment that would allow the communication.

Also, I am thinking of the use of bluetooth, or it looks like in aj's link that with the ethernet shield, it could be connected to a router.

ajlapp 11-12-2011 22:08

Re: Arduino Board and FRC Victors
 
Quote:

@ajlapp - Was looking around on the site and looks interesting, do you have a document that explains how it is setup?
No specific document exists at this time, sorry. The source code for both the robot side and operator side is available at the link previously provided.

In general each side of this system has an Arduino and an Ethernet shield. We used Asus routers to communicate.

Everything we use in the system is open-source and available in various libraries.

For the linked project we chose to have an Arduino on the operator side for portability, but this isn't necessary. We typically build these setups with just a laptop on the driver side.

In the very near future this system will be available in a low-cost consumer ready package. It's very cool and very open. :D


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