Which communication protocol is best?

[Jay_To_The_Be]

I'm just modifying the code I wrote for a practice bot. I want to replace the joystick x&y variables with the x&y variables being sent from processing. I understand the the workstation, I just don't know how to setup up the connection between the cRIO and PROCESSING , and how to separate a comma-delimited string and make those values.

This is my original code that i'm modifying:

#include "WPILib.h"

class Stan : public IterativeRobot {

Jaguar *leftFront;
Jaguar *leftRear;
Jaguar *rightFront;
Jaguar *rightRear;

Joystick *driveStick;

Encoder *leftEncoder;
Encoder *rightEncoder;

Solenoid *shifter;


Gyro *moeGyro;

Compressor *moeCompressor;

DriverStation *ds;

DriverStationLCD *dsLCD;

int teleopLoop;
int disabledLoop;
int autoLoop;

public:
	
	Stan(void)			{
			
			leftFront = new Jaguar(1);
			leftRear = new Jaguar(2);
			rightFront = new Jaguar(3);
			rightRear = new Jaguar(4);
			
			driveStick = new Joystick(1);
			
			leftEncoder = new Encoder(1,2,true,Encoder::k1X);
			rightEncoder = new Encoder(3,4,false,Encoder::k1X);

			moeGyro = new Gyro(1);
			
			moeCompressor = new Compressor(7,1);
			
			ds = DriverStation::GetInstance();
			
			dsLCD = DriverStationLCD::GetInstance();
			
	}
			
	void RobotInit(void)	{
				
		leftEncoder->Start();
		rightEncoder->Start();
				
		moeCompressor->Start();
					
		shifter->Set(false);
	}

	void DisabledInit(void)		{

		disabledLoop = 0;
		
	}
	
	void TeleopInit(void)	{
	
		teleopLoop = 0;
	
	}

	void AutonomousInit(void)	{
		
		autoLoop = 0;
		
		leftEncoder->Reset();
		rightEncoder->Reset();
		
		moeGyro->Reset();
	
	}
	
	void DisablePeriodic(void)	{
		
		disabledLoop = disabledLoop +1;
	
	}
	
	void TeleopPeriodic(void)	{
		
		teleopLoop++;
		
		float X = driveStick->GetX();
		float Y = driveStick->GetY();
		
		if (X<0.1 && X>0.1)	X = 0.0;
		
		if (Y<0.1 && Y>0.1)	Y=0.0;
		
		X = Y + X;
		Y = X - Y;
		
		moeDrive(X, Y);
		
		controlShifter();
		
		int leftDist = leftEncoder->GetRaw();
		
		if (teleopLoop % 10==0)	{
			dsLCD->Printf(DriverStationLCD::kUser_Line1, 1, "L = %d", leftDist);
			
			dsLCD->UpdateLCD();
		}
	
	}
		
	void AutonomousPeriodic(void)	{
		
		autoLoop++;
		
		if (ds->GetDigitalIn(1))	{
			autoLoop++;
		}
	
	}
	
	void controlShifter(void)	{
		if (driveStick->GetTrigger())	{
			shifter->Set(true);
			}
		else	{
			shifter->Set(false);
			}
	}
	void moeDrive(float leftSpeed, float rightSpeed)	{
		
		if (leftSpeed > 1.0) leftSpeed = 1.0;
		else if (leftSpeed < -1.0) leftSpeed = -1.0;

		if (rightSpeed > 1.0) rightSpeed = 1.0;
		else if (rightSpeed < -1.0) rightSpeed = -1.0;
		
		leftFront->Set(leftSpeed);
		leftRear->Set(leftSpeed);
		rightFront->Set(rightSpeed);
		rightRear->Set(rightSpeed);
	}
	
};

START_ROBOT_CLASS(Stan);

[Domenic Rodriguez]

You should take a look at this thread, as it discusses TCP/IP communication with WindRiver C++: http://www.chiefdelphi.com/forums/sh...d.php?t=100810

Mentioned within is Team 3574's 2012 code, which used a TCP to send vision data from the driver station laptop. Here's a link: https://github.com/jacob9706/HighTekerz2012. You might be able to use it as a starting point.

[RyanCahoon]

Originally Posted by Jay_To_The_Be

I just don't know how to setup up the connection between the cRIO and Processing, and how to separate a comma-delimited string and make those values.

Originally Posted by DomenicR

Mentioned within is Team 3574's 2012 code, which used a TCP to send vision data from the driver station laptop.

You can also check out the Network Tables code in the WPILib source code, which includes a TCP server. VxWorks looks like it basically uses the Berkeley/POSIX sockets API, so any resources on the Internet for Linux or Unix socket code should work as well. The code is a little extensive to replicate in-thread.

As for parsing delimited strings, here's some code for that separates numbers delimited by whitespace:

Spoiler for Parse whitespace-delimited numbers:

#include <string>
#include <sstream>
#include <iterator>
#include <vector>

#include <iostream>

int main(int argc, char **argv)
{
	if (argc != 2)
		return 1;
	
	std::string input(argv[1]);
	std::stringstream ss(input);
	std::vector<double> parts((std::istream_iterator<double>(ss)), (std::istream_iterator<double>()));
	if (ss.fail() && !ss.eof())
	{
		std::cout << "Data format error" << std::endl;
		return -1;
	}
	
	for(int i=0; i < parts.size(); ++i)
	{
		std::cout << parts[i] << std::endl;
	}
	
	return 0;
}

if you need comma to be delimiters as well, the code gets a bit more complicated:

Spoiler for Parse comma- and whitespace-delimited numbers:

#include <string>
#include <sstream>
#include <vector>
#include <cctype>

#include <iostream>

int main(int argc, char **argv)
{
	if (argc != 2)
		return 1;
	
	std::string input(argv[1]);
	std::stringstream ss(input);
	std::vector<double> parts;
	double val;
	
	while(ss >> val)
	{
		parts.push_back(val);
		
		while(std::isspace(ss.peek()) || ss.peek() == ',')
			ss.ignore();
	}
	if (!ss.eof())
	{
		std::cout << "Data format error" << std::endl;
		return -1;
	}
	
	for(int i=0; i < parts.size(); ++i)
	{
		std::cout << parts[i] << std::endl;
	}
	
	return 0;
}

[ekapalka]

Originally Posted by Jay_To_The_Be

PROCESSING

Thanks for the extra bold extra italicized clarification. Sorry, sir, but I don't believe I know the solution to your problem.