| pblankenbaker |
20-01-2014 10:30 |
Re: Help using Network Tables with Command Base Bot
Hello:
I'm not entirely sure how you want to interact with your command based robot. The RobotComm class (at the end of this post) provides an example of firing off a command from a stand alone Java application running on the Driver Station.
Using this class involves some coordination on both the robot and your stand-lone Java program. For example, on the robot, if you add something like the following (NOTE: This should also add a button to your Smart Dashboard that you can click on to verify the command works):
Code:
// Install command button on dashboard to fire ball
SmartDashboard.putData("Fire Ball", new FireBallCommand());
You should then be able to start the "FireBallCommand()" from your stand alone Java application running on the driver station using something like the following:
Code:
class MyApp {
private RobotComm robotComm;
public MyApp(String ip) {
robotComm = new RobotComm(ip);
}
public void run() {
// Wait for target to go hot (you'll need to implement the decision)
// waitForHotDetect();
// Now that target is detected, fire the ball
robotComm.startSmartDashboardCommand("Fire Ball");
// Don't immediately exit the program as it may take a moment for the network tables to sync up.
robotComm.sleepMillis(500);
}
public void static main(String[] args) {
MyApp app = new MyApp((args.length == 1) ? args[0] : "10.8.68.2");
app.run();
}
}
In addition to firing off commands, you can also get/set values via the network tables. For example, if you had a stand alone application that just wanted to report the state of the left and right goals, you might add a method like the following:
Code:
public void reportGoalState(boolean leftHot, boolean rightHot) {
NetworkTable sd = robotComm.getSmartDashboard();
sd.putBoolean("Left Hot", leftHot);
sd.putBoolean("Right Hot", rightHot);
}
The code running on the robot could then looks use something like the following to check: SmartDashboard.getBoolean("Left Hot", false);
Here is the source code for the RobotComm class used in the stand alone Java application running on the Driver Station. NOTE: To use this class in your Java projects, you will need to add the networktables-desktop.jar file found in the "sunspotfrcsdk/desktop-lib" folder under your home directory (this is placed here by the FRC Netbeans Java plug-ins).
Code:
/*
* Copyright (c) 2013, pkb
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package com.techhounds.comm;
import edu.wpi.first.wpilibj.networktables.NetworkTable;
import edu.wpi.first.wpilibj.tables.ITable;
/**
* A helper class to demonstrate how to use the {@link NetworkTable} class in a
* stand alone Java application to communicate with the robot.
*
* @author Paul Blankenbaker
*/
public final class RobotComm {
/**
* Flag set if we happen to be interrupted.
*/
private boolean _Interrupted;
/**
* Used when you want to communicate using the SmartDashboard fields.
*/
private NetworkTable _SmartDashboard;
/**
* The key to use to control a smart dashboard command.
*/
private static final String ENABLE_COMMAND_KEY = "running";
/**
* Constructs a new instance of the object associated with a specific IP
* address.
*
* @param ipAddr The IP address of the cRIO unit on your robot (10.xx.xx.2
* where xx.xx comes from your team number).
*/
public RobotComm(String ipAddr) {
_Interrupted = false;
NetworkTable.setClientMode();
NetworkTable.setIPAddress(ipAddr);
_SmartDashboard = NetworkTable.getTable("SmartDashboard");
}
/**
* Returns access to the NetworkTable associated with the SmartDashboard
* values.
*
* <p>
* You can use this table to set/get values within the SmartDashboard. NOTE:
* Use the TableViewer utility to examine the keys/values currently
* available from your robot. Look for the TableViewer JAR file to launch
* this tool in your sunspotfrcsdk/tools directory.</p>
*
* @return The NetworkTable where the SmartDashboard holds it key/value
* pairs.
*/
public NetworkTable getSmartDashboard() {
return _SmartDashboard;
}
/**
* Starts a SmartDashboard command.
*
* <p>
* This method attempts to start a smart dashboard command (as if user press
* the button on the smart dashboard).</p>
*
* @param key The name of the SmartDashboard command to start (typically the
* label that appears on the button on the smart dashboard).
*/
public void startSmartDashboardCommand(String key) {
getCommand(key).putBoolean(ENABLE_COMMAND_KEY, true);
}
/**
* Cancels (interrupts) a SmartDashboard command.
*
* <p>
* This method attempts to start a smart dashboard command (as if user press
* the button in the cancel state on the smart dashboard).</p>
*
* @param key The name of the SmartDashboard command to start (typically the
* label that appears on the button on the smart dashboard).
*/
public void cancelSmartDashboardCommand(String key) {
getCommand(key).putBoolean(ENABLE_COMMAND_KEY, false);
}
/**
* Helper method to get the table of values associated with with a
* SmartDashboard command.
*
* @param key The key (name) associated with the command.
*
* @return The table of values associated with the key.
*/
private ITable getCommand(String key) {
return getSmartDashboard().getSubTable(key);
}
/**
* Returns true if we were ever interrupted while sleeping.
*
* @return true if we've been interrupted, false if not.
*/
public boolean interrupted() {
return _Interrupted;
}
/**
* Sleeps for the specified amount of time (unless interrupted).
*
* @param millis Number of milliseconds to sleep/delay. Note, we may sleep
* less than this if the thread is interrupted.
*/
public void sleepMillis(int millis) {
try {
Thread.sleep(millis);
} catch (InterruptedException e) {
_Interrupted = true;
}
}
}
Hope that helps,
Paul |
