Java | CAN Sparkmax control Using Set

In Java, using the set command with a CANSparkmax will control the motor’s speed.

Prerequisites: Installation of revlib 3rd party library

The sparkmax is a motor controller developed by RevRobotics. It’s typically controlled through the CAN bus and requires more complex commands than just a PWM signal. To alleviate this, RevRobotics has created their own code library, revlib, which requires installation.

Within VScode command pallet (ctrl+shift+p)

>WPIlib: Manage Vendor libraries -> Install New Library Online -> https://software-metadata.revrobotics.com/REVLib-2024.json

Revlib installation instructions

Syntax: motorcontroller_name.set(double speed)

Parameters:

• speed: value from -1.0 to 1.0 where 0 is stopped

Example:

package frc.robot;

import edu.wpi.first.wpilibj.TimedRobot;
//0. Import CANSparkMax (VS code may do this for you)
import com.revrobotics.CANSparkMax;
import com.revrobotics.CANSparkLowLevel.MotorType;

public class Robot extends TimedRobot {
  //1. declare PWMSpark max motor
  public CANSparkMax basicMotor;

  @Override
  public void robotInit() {
    //2. Initialize basic motor with CAN id and motor type
    basicMotor = new CANSparkMax(1, MotorType.kBrushless);
  }

  @Override
  public void teleopPeriodic() {
    //3. Run the motor at 50% speed counter clockwise
    basicMotor.set(0.5);
  }
}

The above example shows the steps to run a CAN Sparkmax with the “timed robot template” in vs code. But that’s not super useful! Here’s an example of controlling it with a button on you joystick:

package frc.robot;

// import Joystick (VS code may automatically do this)
import edu.wpi.first.wpilibj.Joystick;
import edu.wpi.first.wpilibj.TimedRobot;
//0. Import CANSparkMax (VS code may do this for you)
import com.revrobotics.CANSparkMax;
import com.revrobotics.CANSparkLowLevel.MotorType;

public class Robot extends TimedRobot {
  // declare the joystick object
  public Joystick joystick;
  // declare CANSpark max motor
  public CANSparkMax basicMotor;
  

  @Override
  public void robotInit() {
    //Initialize the joystick to port 0
    joystick = new Joystick(0);
    //Initialize basic motor with CAN id and motor type
    basicMotor = new CANSparkMax(1, MotorType.kBrushless);
  }

  @Override
  public void teleopPeriodic() {
    //if joystick button 1 is pressed
    if (joystick.getRawButton(1) == true) {
      // Run the motor at 100% speed clockwise
      basicMotor.set(-1.0);
    } 
    else {
      //if button isn't pressed, stop the motor
      basicMotor.set(0.0);
    }
  }
}

Full code examples can be found here: https://github.com/sweddavid178/FRCExamples/tree/main/Sparkmax

If you have questions or requests reach out to contact.rcrobot@gmail.com