Ultrasonic programming (1st code)

 #define VCC2  4

#define GND2  7

#define L  13

const int T = 5;

const int E = 6;

long duration;

int distanceInch;

int timer;

void setup() {

  

 pinMode(T,OUTPUT);

 pinMode(E,INPUT);

 pinMode(VCC2,OUTPUT);

 digitalWrite(VCC2, HIGH);

 pinMode(GND2,OUTPUT);

 digitalWrite(GND2, LOW);

 pinMode(L,OUTPUT);

 

}

void loop() {

   

 digitalWrite(T, LOW);

 delayMicroseconds(2);

 digitalWrite(T, HIGH);

 delayMicroseconds(10);

 digitalWrite(T, LOW);

 duration = pulseIn(E, HIGH);

 distanceInch = duration*0.0133/2;

if(distanceInch < 2){

digitalWrite(L,HIGH);

delay(500);

}

else{

digitalWrite(L,LOW);

}}