//Since we are using servos and ultrasonic sensors in the robot we will include some libraries written to make their use easier
#include <Servo.h>
#include <NewPing.h>
//Below are the symbolic constants. Instead of having to type in a non-sensical pin number each time we want to do something we can write an easy to understand name which represents the pin, the compiler will then replace the names with the numbers
#define LeftMotorForward 2
#define LeftMotorBackward 3
#define RightMotorForward 5
#define RightMotorBackward 4
#define USTrigger 8
#define USEcho 9
#define MaxDistance 100
#define LED 13
//Here we have created two ‘objects’, one for the servo and one for the ultrasonic sensorServo servo;
NewPing sonar(USTrigger, USEcho, MaxDistance);
//Below we are creating unsigned integer variables which we will use later on in the code. They are unsigned as they will only have postive valuesunsignedint duration;
unsignedint distance;
unsignedint FrontDistance;
unsignedint LeftDistance;
unsignedint RightDistance;
unsignedint Time;
unsignedint CollisionCounter;
voidsetup() //This block happens once on startup
{
Serial.begin(9600); //I have included the serial initialize but commented it out, if you want to debug and print information to the serial monitor just uncomment//Here we are setting the pin modes. As we will sending out signals from the pins we set them as outputspinMode(LeftMotorForward, OUTPUT);
pinMode(LeftMotorBackward, OUTPUT);
pinMode(RightMotorForward, OUTPUT);
pinMode(RightMotorBackward, OUTPUT);
pinMode(LED, OUTPUT);
servo.attach(6); //The servo is attached to pin 4
}
voidloop() //This block repeats itself while the Arduino is turned on
{
servo.write(90); //Rotate the servo to face the front
scan(); //Go to the scan function
FrontDistance = distance; //Set the variable FrontDistance to the value of the distance returned from the scan functionSerial.println("Front distance = ");
Serial.print(distance);
if(FrontDistance > 40 || FrontDistance == 0) //If there is nothing infront of the robot within 40cm or the distance value is 0 (which for the newping libary means no ping was returned) then…
{
moveForward(); //Go to the moveForward function
}
else//Else (if there is something infront of the robot within 40cm) then…
{
CollisionCounter = CollisionCounter + 1;
moveStop(); //Go to the moveStop function
navigate();
}
}
void moveForward() //This function tells the robot to go forward
{
Serial.println("");
Serial.println(“Moving forward”);
digitalWrite(LeftMotorBackward, LOW);
digitalWrite(LeftMotorForward, HIGH);
digitalWrite(RightMotorBackward, LOW);
digitalWrite(RightMotorForward, HIGH);
}
void moveBackward() //This function tells the robot to move backward
{
Serial.println("");
Serial.println(“Moving backward”);
digitalWrite(LeftMotorForward, LOW);
digitalWrite(LeftMotorBackward, HIGH);
digitalWrite(RightMotorForward, LOW);
digitalWrite(RightMotorBackward, HIGH);
}
void moveLeft() //This function tells the robot to turn left
{
Serial.println("");
Serial.println(“Moving left”);
digitalWrite(LeftMotorForward, LOW);
digitalWrite(LeftMotorBackward, HIGH);
digitalWrite(RightMotorBackward, LOW);
digitalWrite(RightMotorForward, HIGH);
}
void moveRight() //This function tells the robot to turn right
{
Serial.println("");
Serial.println(“Moving right”);
digitalWrite(LeftMotorBackward, LOW);
digitalWrite(LeftMotorForward, HIGH);
digitalWrite(RightMotorForward, LOW);
digitalWrite(RightMotorBackward, HIGH);
}
void moveStop() //This function tells the robot to stop moving
{
Serial.println("");
Serial.println(“Stopping”);
digitalWrite(LeftMotorBackward, LOW);
digitalWrite(LeftMotorForward, LOW);
digitalWrite(RightMotorForward, LOW);
digitalWrite(RightMotorBackward, LOW);
}
void scan() //This function determines the distance things are away from the ultrasonic sensor
{
Serial.println("");
Serial.println(“Scanning”);
Time = sonar.ping();
distance = Time / US_ROUNDTRIP_CM;
delay(500);
}
void navigate()
{
Serial.println(“There’s an obstacle!”);
servo.write(167); //Move the servo to the left (my little servos didn’t like going to 180 so I played around with the value until it worked nicely)delay(1000); //Wait half a second for the servo to get there
scan(); //Go to the scan function
LeftDistance = distance; //Set the variable LeftDistance to the distance on the leftSerial.println("Left distance = ");
Serial.print(distance);
servo.write(0); //Move the servo to the rightdelay(1000); //Wait half a second for the servo to get there
scan(); //Go to the scan function
RightDistance = distance; //Set the variable RightDistance to the distance on the rightSerial.println("Right distance = ");
Serial.print(distance);
if(abs(RightDistance - LeftDistance) < 5)
{
moveBackward(); //Go to the moveBackward functiondelay(200); //Pause the program for 200 milliseconds to let the robot reverse
moveRight(); //Go to the moveRight functiondelay(100); //Pause the program for 200 milliseconds to let the robot turn right
}
elseif(RightDistance < LeftDistance) //If the distance on the right is less than that on the left then…
{
moveLeft(); //Go to the moveLeft functiondelay(100); //Pause the program for half a second to let the robot turn
}
elseif(LeftDistance < RightDistance) //Else if the distance on the left is less than that on the right then…
{
moveRight(); //Go to the moveRight functiondelay(100); //Pause the program for half a second to let the robot turn
}
}
so my issues are my servo is not working proper my ping sensor isnt either and only the left motor spins.constantly. any thoughts or ideas?
