int ledPin = 11; int buzzerPin = A0; long duration, cm; int TriggerOut = 6; int TriggerIn = 7; int val; int state; void setup() { pinMode(3,OUTPUT); // trig pin pinMode(4, INPUT); // echo pin pinMode(ledPin,OUTPUT); // set the siren pin as output pinMode(TriggerOut, OUTPUT); pinMode(TriggerIn, INPUT); int val = 0; int state = 0; digitalWrite(2,LOW); // safety feature: connect GND then VCC digitalWrite(5,LOW); // safety feature: connect GND then VCC delay(500); // safety feature: connect GND then VCC digitalWrite(2,HIGH);// safety feature: connect GND then VCC //Serial.begin(9600); // for display distance } void loop() { val = digitalRead(TriggerIn); //*********code mesures time for the sound to bounce back from an object********** digitalWrite(3, HIGH); // turn on trigger delayMicroseconds(5); digitalWrite(3, LOW); //turn trigger off duration = pulseIn(4, HIGH); // measure time for sound wave to come back cm = duration/58; if (cm<5){ digitalWrite(TriggerOut, HIGH); }else{ digitalWrite(TriggerOut, LOW); } if (val == HIGH){ state = 1 - state; delay(1000); } if (state == 1){ digitalWrite(ledPin, HIGH); }else{ digitalWrite(ledPin, LOW); } // Serial.print(cm); // converts microseconds to centrimeters //Serial.println("cm"); }