How to make a remote controlled car using Sun Spots

Here we will see how we can make remote controlled car using Sun SPOTs powered by Java!!

Requirements:

1. Sun SPOT Kit. (Two Sun SPOTs)

2. IC L2393D.

3. DC Motors 2 Nos.

4. A car which you can dismantle and control using DC Motors having enough space to accomodate Sun SPOT and circuit..

5. Patience and some nice coffee and refreshments!!!

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Hardware:

The Hardware basically centers around Sun SPOTs and DC Motors controlled by IC L293D.

The Basic Model is as Follows:

Here remote Sun SPOT will send data to Sun SPOT on car which will drive the IC according to DC IO pins D0 - D3. The IC will drive the Motors which will run the car.

The circuit diagram for the IC is as follows. I think its self explanatory.

---

Software:

The Software consist of two parts:

1. Remote Control Spot.

Make a new Sun Spot Application say - "RemoteSpot" and add the following code to the StartApp file:

package org.sunspotworld.demo;
 
import com.sun.spot.io.j2me.radiogram.Radiogram;
import com.sun.spot.io.j2me.radiogram.RadiogramConnection;
import com.sun.spot.peripheral.NoRouteException;
import com.sun.spot.peripheral.Spot;
import com.sun.spot.peripheral.radio.IRadioPolicyManager;
import com.sun.spot.sensorboard.EDemoBoard;
import com.sun.spot.sensorboard.peripheral.ITriColorLED;
import com.sun.spot.sensorboard.peripheral.IAccelerometer3D;
import java.io.IOException;
import javax.microedition.midlet.MIDletStateChangeException;
import com.sun.spot.util.IEEEAddress;
import com.sun.spot.util.Utils;
import javax.microedition.io.Connector;
 
 /**
 * Remote Spot will send Tilt values to the Car Spot.
 * 
 * @author Jay Mahadeokar
 */
 
public class StartApp extends javax.microedition.midlet.MIDlet {
 
    EDemoBoard demoboard = EDemoBoard.getInstance();
 
    protected void startApp() throws MIDletStateChangeException {
 
        IRadioPolicyManager rpm = Spot.getInstance().getRadioPolicyManager();
        IEEEAddress myAddr = new IEEEAddress(rpm.getIEEEAddress());
        System.out.println("Hi! my address = " + myAddr.asDottedHex());
 
        //This is my Car Sun SPOT address 
        IEEEAddress bsAddress = new IEEEAddress(new String("0014.4F01.0000.1231")); 
        IAccelerometer3D acc = demoboard.getAccelerometer();      
 
        while(true)
        {
            try{
                RadiogramConnection conn = (RadiogramConnection)Connector.open("radiogram://0014.4F01.0000.1A29:10");
                Radiogram rdg = (Radiogram)conn.newDatagram(conn.getMaximumLength());
                try
                {
                    //Get control called and value sent to car spot!
                    rdg.writeUTF(""+getControl());
                    conn.send(rdg);
                    Utils.sleep(200);  // Sleep for sometime!
                }
                catch (NoRouteException e)
                {
                    System.out.println ("No route to 0014.4F01.0000.1A29");
                }
                finally
                {
 
                    conn.close();
                }
            }
            catch(IOException e){
                System.out.println("There is a problem opening the connection");
            }
        }
 
    } 
 
    //Returns the numeric value corresponding to the current Tilt Positions of
    //Sun SPOT
    //Return values only if Tilt > 0.5 or Tilt < -0.5
    public int getControl()
    {
        int ret = 0;
        try {
 
            double xTilt = demoboard.getAccelerometer().getTiltX();
            double yTilt = demoboard.getAccelerometer().getTiltY();
 
            if (xTilt > 0.5 && yTilt < 0.5 && yTilt > -0.5) {
                ret = 110;
            }
            if (xTilt < -0.5 && yTilt < 0.5 && yTilt > -0.5) {
                ret = 101;
            }
            if (yTilt > 0.5 && xTilt < 0.5 && xTilt > -0.5) {
                ret = 100;
            }
            if (yTilt < -0.5 && xTilt < 0.5 && xTilt > -0.5) {
                ret = 1000;
            }
 
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        return ret;
    }
 
    protected void destroyApp(boolean unconditional) throws MIDletStateChangeException {
        ITriColorLED [] leds = EDemoBoard.getInstance().getLEDs();
        for (int i = 0; i < 8; i++) {           // turn off the LEDs when we exit
            leds[i].setOff();
        }
    }
 
    protected void pauseApp() {
    }
 
}

---

2. Car Spot Application.

Make another Sun Spot App and add following code to StartApp. This Spot will be placed on Car and will drive the IC.

package org.sunspotworld.demo;
 
import com.sun.spot.io.j2me.radiogram.Radiogram;
 
import com.sun.spot.io.j2me.radiogram.RadiogramConnection;
 
import com.sun.spot.peripheral.NoRouteException;
 
import com.sun.spot.peripheral.Spot;
 
import com.sun.spot.sensorboard.EDemoBoard;
 
import com.sun.spot.sensorboard.peripheral.ITriColorLED;
 
import javax.microedition.midlet.MIDletStateChangeException;
 
import com.sun.spot.sensorboard.io.IIOPin;
 
import com.sun.spot.sensorboard.peripheral.LEDColor;
 
import com.sun.spot.util.IEEEAddress;
 
import javax.microedition.io.Connector;
 
 /**
 
 *  Listens to the Tilt values being sent by the Remote Spots
 
 *  Changes DC IO Pin values accordingly.
 
 * 
 
 * @author Jay Mahadeokar
 
 */
 
public class StartApp extends javax.microedition.midlet.MIDlet {
 
    private IIOPin[]  pins = EDemoBoard.getInstance().getIOPins(); 
 
    private ITriColorLED[] leds = EDemoBoard.getInstance().getLEDs();
 
    protected void startApp() throws MIDletStateChangeException {
 
        IEEEAddress myAddr = new IEEEAddress(Spot.getInstance().getRadioPolicyManager().getIEEEAddress());
 
        System.out.println("Hi! my address = " + myAddr.asDottedHex());
 
        while(true)
 
        {
 
            try
 
             {
 
                RadiogramConnection conn = (RadiogramConnection) Connector.open("radiogram://:10");
 
                Radiogram rdg = (Radiogram)conn.newDatagram(conn.getMaximumLength());
 
                try 
 
                {
 
                    conn.receive(rdg);   
 
                    String s = rdg.readUTF();
 
                    int state = Integer.parseInt(s);
 
                    System.out.println("state: "+state);
 
                    boolean b[] = new boolean[4];
 
                    for(int i=0;i<4;i++)
 
                    {
 
                        if(state%10 == 1)
 
                            b[i] = true;
 
                        else
 
                            b[i] = false;
 
                        System.out.println(""+b[i]);
 
                        state = state/10;
 
                    }
 
                    setSignal(b);
 
                }
 
                catch (NoRouteException e)
 
                {
 
                    System.out.println("No route to any one ...");
 
                }
 
                finally
 
                {
 
                    conn.close();
 
                }
 
            }
 
            catch(Exception e){
 
               System.out.println("A problem opening the connection ..."); 
 
            }
 
        }
 
   } 
 
    public void setSignal(boolean b[])
 
    {
 
        for(int i=0;i<4;i++)
 
        {
 
            leds[i].setColor(LEDColor.CYAN);
 
            if(b[i] == true)
 
            {
 
                pins[i].setHigh();
 
                leds[i].setOn();
 
            }
 
            else
 
            {
 
                pins[i].setLow();
 
                leds[i].setOff();
 
            }
 
        }
 
    }
 
    protected void destroyApp(boolean unconditional) throws MIDletStateChangeException {
 
        for (int i = 0; i < 8; i++) {           // turn off the LEDs when we exit
 
            leds[i].setOff();
 
        }
 
    }
 
    protected void pauseApp() {
 
    }
 
}

---

Thats It!!! Now biuld the Apps and Deploy On Sun SPOTs. Mount the Car SPOT on Car and control it using Remote Spot!!

You can control car by tilting Spot:

Left - To Move left and accelarate.

Right - To move Right and Accelarate.

Down - To Move the Car Forward.

Up - To Reverse.

Note: The connections of circuit may be really tedious and may take a lot of time!

Thanks a lot to Mr. Abhishek Hisaria who designed the Hardware.

Sun SPOT Controlled Car

See more Pictures at: http://picasaweb.google.com/jai.mahadeokar/SunBlog

Cheers!!