Coding for a lifter?

[Hawk_Prime]

Hi, I'm vincent from FRC team 3229, Hawktimus Prime. We just finished our drive program yesterday and now we need to work on the lift mechanism for our robot so we can pick up totes. The only code we have is one Java file called Robot.java in our project. Here's the code:
package org.usfirst.frc.team3229.robot;


import edu.wpi.first.wpilibj.Joystick;
import edu.wpi.first.wpilibj.RobotDrive;
import edu.wpi.first.wpilibj.RobotDrive.MotorType;
import edu.wpi.first.wpilibj.SampleRobot;
import edu.wpi.first.wpilibj.Timer;

/**
* This is a demo program showing how to use Mecanum control with the RobotDrive class.
*/
public class Robot extends SampleRobot {

RobotDrive robotDrive;
Joystick stick;

// Channels for the wheels
final int frontLeftChannel = 3;
final int rearLeftChannel = 4;
final int frontRightChannel = 2;
final int rearRightChannel = 1;
final int elevator = 6;
// The channel on the driver station that the joystick is connected to
final int joystickChannel = 0;

public Robot() {
robotDrive = new RobotDrive(frontLeftChannel, rearLeftChannel, frontRightChannel, rearRightChannel);
robotDrive.setInvertedMotor(MotorType.kFrontLeft, true); // invert the left side motors
robotDrive.setInvertedMotor(MotorType.kFrontRight, true);
robotDrive.setExpiration(0.1);

stick = new Joystick(joystickChannel);


}


/**
* Runs the motors with Mecanum drive.
*/
public void operatorControl() {
robotDrive.setSafetyEnabled(true);
while (isOperatorControl() && isEnabled()) {

// Use the joystick X axis for lateral movement, Y axis for forward movement, and Z axis for rotation.
// This sample does not use field-oriented drive, so the gyro input is set to zero.
robotDrive.mecanumDrive_Cartesian(stick.getY(), stick.getX(), stick.getZ(), 0);

Timer.delay(0.010); // wait 5ms to avoid hogging CPU cycles
}
}

}


How would I go about just adding something where when you push a button on an xbox controller, a different motor goes? Thanks for the help! :] :)

[notmattlythgoe]

What kind of motor controller are you using? Talon, Victor, or Jaguar?

[cstelter]

How would I go about just adding something where when you push a button on an xbox controller, a different motor goes? Thanks for the help! :] :)

Ultimately I think you'll want to get to


...
SpeedController elevatorMotor;
private static final int LIFT_BUTTON=1; //or whatever button raises
private static final int LOWER_BUTTON=4; //or whatever button lowers

...
public Robot() {
...
elevatorMotor=new Talon(elevator);
...
}

public void operatorControl() {
robotDrive.setSafetyEnabled(true);
while (isOperatorControl() && isEnabled()) {

// Use the joystick X axis for lateral movement, Y axis for forward movement, and Z axis for rotation.
// This sample does not use field-oriented drive, so the gyro input is set to zero.
robotDrive.mecanumDrive_Cartesian(stick.getY(), stick.getX(), stick.getZ(), 0);


if(stick.getRawButton(LIFT_BUTTON)) {
elevatorMotor.set(0.5);
} else if(stick.getRawButton(LOWER_BUTTON)) {
elevatorMotor.set(-0.5);
} else {
elevatorMotor.set(0);
}

Timer.delay(0.010); // wait 5ms to avoid hogging CPU cycles
}
}


but to get there you need some variable representing a SpeedController such as I've shown as elevatorMotor. I showed the code if you use a Talon. If you use something else as Matt was asking about, that line would be different. If you need to call more than just the basic SpeedController interface on you Talon/Jaguar/TalonSRX/etc, you can make the line be


Talon elevatorMotor=new Talon(elevator);


Then if there is a Talon specific function that is not on the SpeedController interface, you can still call that too. Just trying to keep it simple for you.

I've not used xbox class so I don't know if getRawButton is best way to get buttons or not, or if mappings exist avoiding need for LIFT_BUTTON/LOWER_BUTTON, but using local names with explicit names for lift and lower help keep your code more understandable.

[Hawk_Prime]

Thank you!