Border Follower (Autonomous Mode)

Purpose: The EV3 rover (standard model with two motors) equipped with a color or light sensor that distinguishes between a white and a black floor advances along a white-to-black border. The rover moves on a wiggly line and changes from a left to a right curve when the sensor 'sees' the black offshore region.

First you should check the light levels when the sensor detects the white or back floor.

import ch.aplu.ev3.*;

public class BorderFollower
{
  public BorderFollower()
  {
    LegoRobot robot = new LegoRobot();
    LightSensor ls = new LightSensor(SensorPort.S1);
    robot.addPart(ls);
    Gear gear = new Gear();
    gear.setSpeed(20);
    robot.addPart(gear);
    while (!Tools.isEscapeHit())
    {
      if (ls.getValue() < 500)
        gear.leftArc(0.2);
      else
        gear.rightArc(0.2);
    }
    robot.exit();
  }

  public static void main(String[] args)
  {
    new BorderFollower();
  }
}

Compilation/download using the OnlineEditor of PHBern (Bern University of Teacher Education)

Border Follower (Direct Mode)

Purpose: Same as above, but in Direct Mode.

import ch.aplu.ev3.*;

public class BorderFollowerD
{
  public BorderFollowerD()
  {
    LegoRobot robot = new LegoRobot();
    LightSensor ls = new LightSensor(SensorPort.S1);
    robot.addPart(ls);
    Gear gear = new Gear();
    gear.setSpeed(20);
    robot.addPart(gear);
    while (true)
    {
      if (ls.getValue() < 500)
        gear.leftArc(0.2);
      else
        gear.rightArc(0.2);
    }
  }

  public static void main(String[] args)
  {
    new BorderFollowerD();
  }
}

Execute the program locally using WebStart.

Border Follower (Simulation Mode)

Purpose: Same as above, but in Simulation Mode.

import ch.aplu.robotsim.*;

public class BorderFollowerS
{
  public BorderFollowerS()
  {
    LegoRobot robot = new LegoRobot();
    LightSensor ls = new LightSensor(SensorPort.S1);
    robot.addPart(ls);
    Gear gear = new Gear();
    gear.setSpeed(20);
    robot.addPart(gear);
    while (true)
    {
      if (ls.getValue() < 500)
        gear.leftArc(0.2);
      else
        gear.rightArc(0.2);
    }
  }

  public static void main(String[] args)
  {
    new BorderFollowerS();
  }
}

Execute the program locally using WebStart.