GRIP and NetworkTables settings for use with a co-processor

[Kevin K]

My team has successfully written an algorithm to consistently find this year's targets in GRIP. However, for whatever reason we are unable to transmit contour information to our program on the roboRIO. I essentially copied our code line for line from the Java examples on ScreenstepsLive and the GRIP github page, with minor tweaks in order to access the variables we care about. Our GRIP related code is as follows:
In constructor:
table = NetworkTable.getTable("GRIP/myContoursReport");
In operatorControl:
targetWidth = table.getNumber("width", 0);
When we run our program, the default value of zero is always returned. We run GRIP on a separate laptop(we eventually hope to use a Kangaroo on our robot, but it has not arrived yet). In GRIP I have set the NetworkTables server address as roborio-4541-frc.local, and we can view all of the contour information on our main laptop using OutlineViewer in client mode with the server at the same address. I tried running our code as a client as well, but recieved an error stating that there was already an instance of NetworkTables running. This is our first year using NetworkTables, so I do not have the required knowledge to troubleshoot this problem any further on my own(I've already spent a good 2-3 meetings working on this). Any help or advice anyone could give would be much appreciated.

[Peter Johnson]

The robot is always the NetworkTables server. Do you see "client connected" messages on the robot? Are you sure you have the table name / value name correct? A screenshot of what OutlineViewer is showing you would be helpful in debugging.

[Kevin K]

I cannot get to our laptop to take a screenshot at the moment, but I remember that OutlineViewer showed all of the contour information as well as the values being sent to the SmartDashboard. I am positive we have typed in all of the paths correctly. Where might we see this "client connected" message? In the riolog?

[Peter Johnson]

Originally Posted by Kevin K

I cannot get to our laptop to take a screenshot at the moment, but I remember that OutlineViewer showed all of the contour information as well as the values being sent to the SmartDashboard. I am positive we have typed in all of the paths correctly. Where might we see this "client connected" message? In the riolog?

Correct, in riolog (or the driver station console if you turn on prints), you should see "NT: server: client CONNECTED: <ip> port <port>" printed for each NT client that has connected.

[Kevin K]

I just tried it, the correct message displayed in the riolog.

[Peter Johnson]

Originally Posted by Kevin K

I just tried it, the correct message displayed in the riolog.

Ok, there's no reason you shouldn't be able to read the table then. Can you post or PM me a more complete snippet of your code?

[Kevin K]

This is our entire Robot.java class. NetworkTables related code is bolded.


package org.usfirst.frc.team4541.robot;


import edu.wpi.first.wpilibj.SampleRobot;
import edu.wpi.first.wpilibj.SPI;

import com.kauailabs.navx.frc.AHRS;

import edu.wpi.first.wpilibj.CANTalon;
import edu.wpi.first.wpilibj.CameraServer;
import edu.wpi.first.wpilibj.I2C;
import edu.wpi.first.wpilibj.I2C.Port;
import edu.wpi.first.wpilibj.Joystick;
import edu.wpi.first.wpilibj.Timer;
import edu.wpi.first.wpilibj.networktables.NetworkTable;
import edu.wpi.first.wpilibj.smartdashboard.SendableChoos er;
import edu.wpi.first.wpilibj.smartdashboard.SmartDashboar d;

public class Robot extends SampleRobot {
Joystick stick;
TankDrive drive;
CANTalon t1, t2, t3, t4, t5, t6, t7, t8, t9;
MotorManip m1, m2, m3, m4, m5;
Shooter shooter;
Intake intake;
Climber climber;

LIDAR lidar;
final String defaultAuto = "Default";
final String customAuto = "My Auto";
SendableChooser chooser;
AHRS gyro;
NetworkTable table;
CameraServer server;
double targetWidthPx;
double targetDistanceIn;
double desiredX;
double targetOffsetIn;
double targetOffsetDegrees;
// Port port = I2C.Port.kOnboard;

public Robot() {
stick = new Joystick(0);
t1 = new CANTalon(0);
t2 = new CANTalon(1);
t3 = new CANTalon(2);
t4 = new CANTalon(3);
t5 = new CANTalon(4);
t6 = new CANTalon(5);
t7 = new CANTalon(6);
t8 = new CANTalon(7);
t9 = new CANTalon(8);
m1 = new MotorManip(t5);
m2 = new MotorManip(t6);
m3 = new MotorManip(t7);
m4 = new MotorManip(t8);
climber = new Climber(t9);
drive = new TankDrive(t1,t2,t3,t4);
shooter = new Shooter(m1, m2);
intake = new Intake(m3, m4);
// lidar = new LIDAR(port);
gyro = new AHRS(SPI.Port.kMXP);
server = CameraServer.getInstance();
server.setQuality(50);
server.startAutomaticCapture("cam0");
}

public void robotInit() {
chooser = new SendableChooser();
chooser.addDefault("Default Auto", defaultAuto);
chooser.addObject("My Auto", customAuto);
SmartDashboard.putData("Auto modes", chooser);
table = NetworkTable.getTable("GRIP/myContoursReport");
}

public void autonomous() {

// String autoSelected = (String) chooser.getSelected();
// String autoSelected = SmartDashboard.getString("Auto Selector", defaultAuto);
// System.out.println("Auto selected: " + autoSelected);
//
// switch(autoSelected) {
// case customAuto:
// break;
// case defaultAuto:
// default:
// break;
// }
}

public void operatorControl() {
gyro.reset();
while (isOperatorControl() && isEnabled()) {
// lidar.begin(100, 0xff);
// lidar.start(100);
// SmartDashboard.putNumber("Distance", lidar.getDistance());
targetWidthPx = table.getNumber("width", 0);
targetDistanceIn = 3200/(2 * targetWidthPx * Math.tan(25));
desiredX = 0;
targetOffsetIn = (desiredX -table.getNumber("centerX", 0)) * 20/targetWidthPx;
targetOffsetDegrees = Math.tan(targetOffsetIn/targetDistanceIn);
SmartDashboard.putNumber("angle", gyro.getAngle());
SmartDashboard.putNumber("output", Math.abs(.0035*(90-gyro.getAngle())));
SmartDashboard.putNumber("target width", targetWidthPx);
SmartDashboard.putNumber("target distance", targetDistanceIn);
drive.arcadeDrive(drive.modStickIn(stick,1),drive. modStickIn(stick, 4));
if(stick.getRawButton(1)){
drive.rotateToAngle(90, gyro);
}
else if(stick.getRawButton(5)){
drive.speedUp();
}
else if(stick.getRawButton(6)){
drive.slowDown();
}
// else if(stick.getRawButton(2)){
// drive.rotateToAngle(targetOffsetDegrees, gyro);
// shooter.shoot(1,1);
// }
// else if(stick.getRawButton(4)){
// intake.pickUp(1);
// }
//
// else if(stick.getRawButton(5)){
// climber.extend(.5);
// }
//
// else if(stick.getRawButton(6)){
// climber.retract(.5);
// }

}
}


public void test() {
}

}

[Peter Johnson]

Since you're running it now, could you post a screenshot of what OutlineViewer is showing?

My guess is that the data type being put by GRIP is an array rather than a single number?

Edit: yes, looks like it is. See http://wpilib.screenstepslive.com/s/...-networktables

[Kevin K]

I had tried changing it to an array, but I can give it another shot. Here is the screenshot from OutlineViewer

[Peter Johnson]

Yep, those are definitely arrays (albeit 1-element ones).

So you should use getNumberArray() instead, check the size of the result, and get the 0th element.

[Kevin K]

I just tried it again using getNumberArray(); and it still only returns the default value.
Edit: Actually, it turns out that I forgot to recompile. I am getting the data now, thank you so much for all of your help.