#define PIN_TRIG 3
#define PIN_ECHO 2
const int LedPin1 = 12;
const int ButtonPin1 = 11;

void setup() {
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(LedPin1, OUTPUT);
  pinMode(ButtonPin1, INPUT_PULLUP);

}

void loop() {
long duration, distance;
digitalWrite(PIN_TRIG, LOW);
delayMicroseconds(10);
digitalWrite(PIN_TRIG, HIGH);
delayMicroseconds(10);
digitalWrite(PIN_TRIG, LOW); 
duration = pulseIn(PIN_ECHO, HIGH);
distance = (duration/2)/29.1;
Serial.print(distance);
Serial.println("CM");
  if (distance<180){
    digitalWrite(LedPin1, HIGH);
  }else{
    digitalWrite(LedPin1, LOW);
  }
}