Human Following Robot by using Arduino

 CODING & CIRCUIT DIAGRAM

const int trig=11;

const int echo=12;

long d;

int dis;

void setup() {

 pinMode(trig,OUTPUT);

 pinMode(echo,INPUT);

 Serial.begin(9600);

 pinMode(7,OUTPUT);

 pinMode(6,OUTPUT);

 pinMode(5,OUTPUT);

 pinMode(4,OUTPUT);

}

void loop() {

  digitalWrite(trig,LOW);

  delayMicroseconds(2);

   digitalWrite(trig,HIGH);

  delayMicroseconds(2);

   digitalWrite(trig,LOW);

  d=pulseIn(echo,HIGH);

  dis=d*0.034/2;

if (dis>=30 && dis<= 40){

  digitalWrite(7,HIGH);

  digitalWrite(6,LOW);

  digitalWrite(5,HIGH);

  digitalWrite(4,LOW);

}

else if (dis>=1 && dis<=15){

  digitalWrite(6,HIGH);

  digitalWrite(7,LOW);

  digitalWrite(4,HIGH);

  digitalWrite(5,LOW);

}

else {

  digitalWrite(7,LOW);

  digitalWrite(6,LOW);

  digitalWrite(5,LOW);

  digitalWrite(4,LOW);

}

Serial.println(dis);

}