gistfile1.txt

#include <Boards.h>
#include <Firmata.h>


#define trigPin 12
#define echoPin 13
int Buzzer = 8;

bool bJustBuzzed = false;
int lastBuzzed = 0;
int buzzTimeout = 30*1000;

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(Buzzer, OUTPUT);
}

void loop() {
  
  int duration, distance;
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(1500);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;

  if(!bJustBuzzed) {
    if ( (distance >= 200 || distance <= 100) ) {
      Serial.println("no object detected");
      digitalWrite(Buzzer, LOW);
    }
    else {
      Serial.println("object detected");
           
      tone(Buzzer, 1500); // play 400 Hz tone for 500 ms
      delay(300);
      
      noTone(Buzzer);
      bJustBuzzed = true;
      lastBuzzed = millis();
    }
  }

  if(bJustBuzzed) {
    if( (millis() - lastBuzzed) > buzzTimeout) {
      bJustBuzzed = false;
    }
  }
  
delay(100);
}