Rover Extensions

Light Tracking Rover

Control your rover using light!

Start

Prerequisites Parts Setup Move Write Code Run Program Practice

Prerequisites

Make sure you have completed the following projects before starting

Parts

Make sure you have all the parts before moving on.

Note: you can use any Phidget with an accelerometer for this project.

Kits/ Kit4004

Phidget Rover

Sensors / LUX1000

Light Phidget (2)

Cables/ 3003

Phidget Cable (2)

Setup

Step 1

You should have an assembled rover.

Step 2

Remove the Sonar Phidget and mount the two Light Phidgets on an angle, facing outwards.

The Light Phidget pointing to the left should be on Hub Port 4 and the other Light Phidget should be on Hub Port 3.

Move

To create an autonomous vehicle, the rover must receive all of its directions from the light sensors. By measuring the difference between the light intensity of each sensor, you can turn the rover towards the brighter side.

For example, in the image above, sensor on the right receives a greater share of light. With this input, the rover should turn to the left.

Write Code (Java)

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package phidgetsrover;

//Add Phidgets Library
import com.phidget22.*;

public class PhidgetsRover {
    public static void main(String[] args) throws Exception{

        //Connect to wireless rover
        Net.addServer("", "192.168.100.1", 5661, "", 0);

        //Create
        LightSensor leftLight = new LightSensor();
        LightSensor rightLight = new LightSensor();
        DCMotor leftMotors = new DCMotor();
        DCMotor rightMotors = new DCMotor();

        //Address
        leftMotors.setChannel(0);
        rightMotors.setChannel(1);
        rightLight.setHubPort(3);
        leftLight.setHubPort(4);

        //Open
        leftLight.open(5000);
        rightLight.open(5000);
        leftMotors.open(5000);
        rightMotors.open(5000);

        //Increase acceleration
        leftMotors.setAcceleration(leftMotors.getMaxAcceleration());
        rightMotors.setAcceleration(rightMotors.getMaxAcceleration());

        //Use your Phidgets
        while (true){

            //Determine which direction to move
            double lightDiff = leftLight.getIlluminance() - rightLight.getIlluminance();
            System.out.println("Light Diff: " + lightDiff);
            
            //If difference is low, do nothing
            if(Math.abs(lightDiff) < 10){
                leftMotors.setTargetVelocity(0);
                leftMotors.setTargetVelocity(0);
            }
            //If there is more light to the left, go left
            else if(lightDiff > 0){
                leftMotors.setTargetVelocity(0.25);
                rightMotors.setTargetVelocity(-0.25);
            }
            //If there is more light to the right, go right
            else{
                leftMotors.setTargetVelocity(-0.25);
                rightMotors.setTargetVelocity(0.25);
            }
            
            //Wait for 250 milliseconds
            Thread.sleep(250);
        }
    }
}

  
//Add Phidgets Library
import com.phidget22.*;

public class PhidgetsRover {
    public static void main(String[] args) throws Exception{

        //Connect to wireless rover
        Net.addServer("", "192.168.100.1", 5661, "", 0);

        //Create
        LightSensor leftLight = new LightSensor();
        LightSensor rightLight = new LightSensor();
        DCMotor leftMotors = new DCMotor();
        DCMotor rightMotors = new DCMotor();

        //Address
        leftMotors.setChannel(0);
        rightMotors.setChannel(1);
        rightLight.setHubPort(3);
        leftLight.setHubPort(4);

        //Open
        leftLight.open(5000);
        rightLight.open(5000);
        leftMotors.open(5000);
        rightMotors.open(5000);

        //Increase acceleration
        leftMotors.setAcceleration(leftMotors.getMaxAcceleration());
        rightMotors.setAcceleration(rightMotors.getMaxAcceleration());

        //Use your Phidgets
        while (true){

            //Determine which direction to move
            double lightDiff = leftLight.getIlluminance() - rightLight.getIlluminance();
            System.out.println("Light Diff: " + lightDiff);
            
            //If difference is low, do nothing
            if(Math.abs(lightDiff) < 10){
                leftMotors.setTargetVelocity(0);
                leftMotors.setTargetVelocity(0);
            }
            //If there is more light to the left, go left
            else if(lightDiff > 0){
                leftMotors.setTargetVelocity(0.25);
                rightMotors.setTargetVelocity(-0.25);
            }
            //If there is more light to the right, go right
            else{
                leftMotors.setTargetVelocity(-0.25);
                rightMotors.setTargetVelocity(0.25);
            }
            
            //Wait for 250 milliseconds
            Thread.sleep(250);
        }
    }
}

  

//Add Phidgets Library 
import com.phidget22.*;

//Define
DCMotor leftMotors;
DCMotor rightMotors;
LightSensor leftLight;
LightSensor rightLight;

void setup(){
  try{
    
    //Connect to wireless rover
    Net.addServer("","192.168.100.1", 5661,"",0);
    
    //Create
    leftMotors = new DCMotor();
    rightMotors = new DCMotor();
    leftLight = new LightSensor();
    rightLight = new LightSensor();
    
    //Address 
    leftMotors.setChannel(0);
    rightMotors.setChannel(1);
    rightLight.setHubPort(3);
    leftLight.setHubPort(4);
    
    //Open
    leftMotors.open(5000);
    rightMotors.open(5000);
    leftLight.open(5000);
    rightLight.open(5000);
    
    //Increase acceleration
    leftMotors.setAcceleration(leftMotors.getMaxAcceleration());
    rightMotors.setAcceleration(rightMotors.getMaxAcceleration());
    
  }catch(Exception e){
    //Handle Exceptions
    e.printStackTrace();
  }
}

void draw(){
  try{
    
    //Determine which direction to move
    double lightDiff = leftLight.getIlluminance() - rightLight.getIlluminance();
    System.out.println("Light Diff: " + lightDiff);
    
    //If difference is low, do nothing
    if(Math.abs(lightDiff) < 10){
        leftMotors.setTargetVelocity(0);
        leftMotors.setTargetVelocity(0);
    }
    //If there is more light to the left, go left
    else if(lightDiff > 0){
        leftMotors.setTargetVelocity(0.25);
        rightMotors.setTargetVelocity(-0.25);
    }
    //If there is more light to the right, go right
    else{
        leftMotors.setTargetVelocity(-0.25);
        rightMotors.setTargetVelocity(0.25);
    }
    
    //Wait for 250 milliseconds
    delay(250);
    
  }catch(Exception e){
    //Handle Exceptions
    e.printStackTrace();
  }
}

Write Code (Python)

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#Add Phidgets Library
from Phidget22.Phidget import *
from Phidget22.Net import *
from Phidget22.Devices.LightSensor import *
from Phidget22.Devices.DCMotor import *
#Required for sleep statement
import time


#Connect to your rover
Net.addServer("", "192.168.100.1", 5661, "", 0)

#Create
leftLight = LightSensor()
rightLight = LightSensor()
leftMotors = DCMotor()
rightMotors = DCMotor()

#Address
leftMotors.setChannel(0)
rightMotors.setChannel(1)
rightLight.setHubPort(3)
leftLight.setHubPort(4)


#Open
leftLight.openWaitForAttachment(5000)
rightLight.openWaitForAttachment(5000)
leftMotors.openWaitForAttachment(5000)
rightMotors.openWaitForAttachment(5000)

#Increase acceleration
leftMotors.setAcceleration(leftMotors.getMaxAcceleration())
rightMotors.setAcceleration(rightMotors.getMaxAcceleration())

#Use your Phidgets
while (True):
    
    #Determine which direction to move
    lightDiff = leftLight.getIlluminance() - rightLight.getIlluminance()
    print("Light Diff:" + str(lightDiff))
    
    #If difference is low, do nothing
    if(abs(lightDiff) < 10):
        leftMotors.setTargetVelocity(0)
        rightMotors.setTargetVelocity(0)
    #If there is more light to the left, go left
    elif(lightDiff > 0):
        leftMotors.setTargetVelocity(0.25)
        rightMotors.setTargetVelocity(-0.25)
    #If there is more light to the right, go right    
    else:
       leftMotors.setTargetVelocity(-0.25)
       rightMotors.setTargetVelocity(0.25) 
        
    #Wait for 250 milliseconds
    time.sleep(0.25)

Write Code (C#)

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//Add Phidgets Library
using Phidget22;

namespace PhidgetsRover
{
    class Program
    {
        static void Main(string[] args)
        {

            //Connect to wireless rover
            Net.AddServer("", "192.168.100.1", 5661, "", 0);

            //Create
            LightSensor leftLight = new LightSensor();
            LightSensor rightLight = new LightSensor();
            DCMotor leftMotors = new DCMotor();
            DCMotor rightMotors = new DCMotor();

            //Address
            leftMotors.Channel = 0;
            rightMotors.Channel = 1;
            rightLight.HubPort = 3;
            leftLight.HubPort = 4;


            //Open
            leftLight.Open(5000);
            rightLight.Open(5000);
            leftMotors.Open(5000);
            rightMotors.Open(5000);

            //Increase acceleration
            leftMotors.Acceleration = leftMotors.MaxAcceleration;
            rightMotors.Acceleration = rightMotors.MaxAcceleration;

            //Use your Phidgets
            while (true)
            {
                //Determine which direction to move
                double lightDiff = leftLight.Illuminance - rightLight.Illuminance;
                System.Console.WriteLine("Light Diff: " + lightDiff);

                //If difference is low, do nothing
                if (System.Math.Abs(lightDiff) < 10)
                {
                    leftMotors.TargetVelocity = 0;
                    rightMotors.TargetVelocity = 0;
                }
                //If there is more light to the left, go left
                else if (lightDiff > 0)
                {
                    leftMotors.TargetVelocity = 0.25;
                    rightMotors.TargetVelocity = -0.25;
                }
                //If there is more light to the right, go right
                else
                {
                    leftMotors.TargetVelocity = -0.25;
                    rightMotors.TargetVelocity = 0.25;
                }

                //Wait for 250 milliseconds
                System.Threading.Thread.Sleep(250);
            }
        }
    }
}

Write Code (Swift)

Swift code sample coming soon. Not your programming language? Set your preferences so we can display relevant code examples

Run Your Program

Your rover will turn in the direction where more light is present. You can test this by using the flashlight on your phone. Complete the practice problems below to add more functionality to your rover.

Practice

Adjust the velocity of the rover until you are satisfied with the turning speed.
Add a forward velocity to your rover so it will follow the light source.
Add the Sonar Phidget to your rover to avoid obstacles.

Back to Rover Projects