Arduino and LabVIEW

[Roger]

After searching high and low here and on the web, I still can't find a definitive answer: How do I send information (numbers) between the cRIO (using LabVIEW) and an Arduino Uno? And what are the actual hardware connections to be made at both ends? Thanks.

[davidthefat]

You can't, I also doubt if the arduino has enough power to run vXWorks either.

[EricVanWyk]

I'm not sure what David is talking about...

You can use I2C, SPI, or serial. Or, you could add an ethernet shield to the Arduino and use that.

For I2C and SPI, the cRIO wants to be the master. I'm not sure if the arduino easily supports slaving in these modes, you will have to check it out.

For serial, the Uno consumes its native serial port with its USB connection. Instead, you will have to use the software serial port library.

[davidthefat]

Originally Posted by EricVanWyk

I'm not sure what David is talking about...

You can use I2C, SPI, or serial. Or, you could add an ethernet shield to the Arduino and use that.

For I2C and SPI, the cRIO wants to be the master. I'm not sure if the arduino easily supports slaving in these modes, you will have to check it out.

For serial, the Uno consumes its native serial port with its USB connection. Instead, you will have to use the software serial port library.

My, bad, I read the question wrong... I thought he was asking how he can program the arduino with labview... Disregard my post

[Andy A.]

Originally Posted by EricVanWyk

I'm not sure what David is talking about...

You can use I2C, SPI, or serial. Or, you could add an ethernet shield to the Arduino and use that.

For I2C and SPI, the cRIO wants to be the master. I'm not sure if the arduino easily supports slaving in these modes, you will have to check it out.

For serial, the Uno consumes its native serial port with its USB connection. Instead, you will have to use the software serial port library.

There is also a CAN bus shield available, although I know little about it. It has a DB9 connector, which I guess means it's really intended to interface with automotive diagnostics stuff (complete with a sd card slot for data logging!). Still, I'm sure a clever team could handle the wiring and code required to interface it on a FIRST bot.

There are, of course, legal issues regarding custom circuits being in the CAN bus loop. Without carefully looking I think using the bus just to pass data is ok, as long as it doesn't try to control motors. I'm not sure exactly what practical advantage it would give you over SPI or I2C, but it would be pretty neat.

CAN bus shield on Sparkfun. It might be avalible elsewhere.

[WizenedEE]

Custom Circuits are explicatively allowed to be on the CAN bus. They are also explicatively illegal to control any non-decorations (and I'm not sure about the rules on decorations). Unless, of course, you email FIRST and get something as an approved motor controller.

I'd most likely try to communicate using I2C, but if you can get the C-RIO to send out serial commands, that's the arduino's native protocall.

[Roger]

Well, we might be but not all that clever, especially when we're short on time. I'll have to check those possibilities, Eric. Where does the data wire(s) get connected? Right now I'm in the "one step back" mode (computer doesn't want to download to the Arduino), so it'll be a bit.

All I need is to send a single number to the Arduino, and it'll turn on some LEDs. Can I do it through a Digital IO (which sounds the simpliest method)? WPI_PWMSetValue.vi?

Just saw Adam's post: Yeah, it's not quite decorative LEDs, so thats out. Any of the LabVIEW I2C examples are good to look at? Or the serial?

[Mark McLeod]

How big a number?

You can simply use the digital outputs on a sidecar to digital inputs on the Arduino to send a binary number.
You don't need a communications protocol to do that.

Maybe use one DIO to signal when the number has changed and should be read by the Arduino.

[Roger]

Do you mean (for example) 4 DIOs sending a binary signal for 16 numbers? (And no, I don't have many numbers, but I can think of ways to expand that.) Just using the signal portion of the PWM wire, right? (The Keeper of the Numbers says we have 5 DIOs free for use.) Heh -- I had thought of that too, when we originally thought of using DIOs. It seemed too obvious to be true. Could it really be that simple? Thanks, Mark!

Of course, I spent the day trying to make connections on an older robot to test all this, and now discovered (after connecting all the dots, so to speak) that LabVIEW and the Arduino programming port don't play nice together. I am making a nice collection of laptops around me just to test this.

[kamocat]

Originally Posted by Roger

Do you mean (for example) 4 DIOs sending a binary signal for 16 numbers? (And no, I don't have many numbers, but I can think of ways to expand that.) Just using the signal portion of the PWM wire, right? (The Keeper of the Numbers says we have 5 DIOs free for use.) Heh -- I had thought of that too, when we originally thought of using DIOs. It seemed too obvious to be true. Could it really be that simple? Thanks, Mark!

Of course, I spent the day trying to make connections on an older robot to test all this, and now discovered (after connecting all the dots, so to speak) that LabVIEW and the Arduino programming port don't play nice together. I am making a nice collection of laptops around me just to test this.

Yes, if you're not doing a high volume of data, this is an easy and viable method.

[Roger]

Well we are talking about an Arduino. But no, just a signal to change lights.

Howsoever, I did see at FLR a team using an Arduino for sonar processing, but I don't know what kind of data they were sending back to the cRIO -- much more than I'm asking for, I'm sure. These little boards are fun to work with.

[Roger]

An update -- I have some LabVIEW code that sends a DIO true/false value depending on a button press, recieved by the Arduino on a digital pin, and blinks the light on the Arduino and also prints out the high/low value (simple test), slowed down to 1/2 second cycle. Currently I'm getting a semi-random highs/lows, even without pressing the button, which I'm guessing is LV's issue, not continually sending the true/false signal? Unfortunately, I lost my LV computer so I can't check it -- maybe I can schedule for a 3 am session?

[WizenedEE]

If you haven't opened the IO port in your code, I think it may leave the signal pin floating. Does it work when you press the button, or does it ignore the button as well?