Arduino Code

int M21=10; //defining the pins of arduino for servo motors
int M12=6;
int M22=9;  //Pin numbers depends on you whichever you wan to take
int M11=11;
int tregpin=4;  //The output pin of ultrasonic sensor
int echopin=2;  //Input pin of Ultrasonic sensor


// the setup function runs once when you press reset or power the board
void setup() {
  Serial.begin(9600);
  // initializing the digital pins as an output or for INPUT.
  pinMode(M12, OUTPUT);
  pinMode(M21, OUTPUT);
  pinMode(tregpin, OUTPUT);
  pinMode(echopin, INPUT);
  pinMode(M22, OUTPUT);
  pinMode(M11, OUTPUT);
}

// here is the loop function that runs continuosly over and over again
void loop() {
  int distance, duration;
  digitalWrite(tregpin,HIGH);  //Ultrasonic sensor send a signal
  delay(1000);
  digitalWrite(tregpin,LOW);
  duration=pulseIn(echopin,HIGH); 
  distance=(duration/2)/29.1;  //Calculate distance using speed-time formula for sound
  Serial.println(distance);

if(distance>10)     // robot will keep moving straight
{
    digitalWrite(M12,HIGH);
    digitalWrite(M22,HIGH);
    digitalWrite(M11,LOW);
    digitalWrite(M21,LOW);
}

if(distance<=10)    //This code will turn the robot to right side
{
    digitalWrite(M11,HIGH);
    digitalWrite(M21,LOW);
    digitalWrite(M22,HIGH);
    digitalWrite(M12,LOW);
    
}

}