int ledPIN = 7; int speakerPIN = 9; int trigPIN = 13; int echoPIN = 11; boolean buttonOn = false; void setup() { // put your setup code here, to run once: pinMode(ledPIN, OUTPUT); pinMode(echoPIN, INPUT); pinMode(trigPIN, OUTPUT); Serial.begin(9600); } void loop() { long duration, distance; digitalWrite(trigPIN,HIGH); delayMicroseconds(1000); digitalWrite(trigPIN,LOW); duration = pulseIn(echoPIN,HIGH); distance = (duration/2)/29.1; Serial.print(distance); Serial.println("CM"); delay(10); if (distance < 10) { digitalWrite(ledPIN, HIGH); tone(speakerPIN,1000); } else { digitalWrite(ledPIN, LOW); noTone(speakerPIN); } }