programming of 4wd robot using ping sensor

Projects Programming
10

this is the whole code

#include <AFMotor.h> 
AF_DCMotor motor1(1, MOTOR12_64KHZ); 
AF_DCMotor motor2(2, MOTOR12_64KHZ); 
AF_DCMotor motor3(3, MOTOR12_1KHZ); 
AF_DCMotor motor4(4, MOTOR12_1KHZ); 
#define trigPin 8
#define echoPin 9

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  motor1.setSpeed(200);         // Set the speed for the motors (255 is the maximum)      
  motor2.setSpeed(200); 
  motor3.setSpeed(200); 
  motor4.setSpeed(200);
}
void forward(){      // This function moves the wheels forward 
    motor1.run(FORWARD); 
  motor2.run(FORWARD); 
  motor3.run(FORWARD); 
  motor4.run(FORWARD);
  
} 
void backward() {      // This function moves the wheels backward 
    motor1.run(BACKWARD); 
  motor2.run(BACKWARD); 
  motor3.run(BACKWARD); 
  motor4.run(BACKWARD); 
} 
void haltMotors()   // This function stops each motor (It is better to stop the motors before changing direction.) 
{ 
  motor1.run(RELEASE); 
  motor2.run(RELEASE); 
  motor3.run(RELEASE); 
  motor4.run(RELEASE); 
} 
void turnRight(){    // This function turns the robot right.   
  motor1.run(FORWARD); 
  motor2.run(BACKWARD); 
  motor3.run(BACKWARD); 
  motor4.run(FORWARD); 
} 
void turnLeft(){
  motor1.run(BACKWARD);
  motor2.run(FORWARD);
  motor3.run(FORWARD);
  motor4.run(BACKWARD);
}

float ping() {
  int duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;
  return distance;
}

void loop(){
  long time, distance;
  distance=ping();

  
  
  Serial.print(distance);
  Serial.print("cm");
  Serial.println();
  
 if (distance >=10){
  turnRight();
  } 
 if (distance <10){
 forward();}  
}