Arduino人体接近报警之三

// Uses a PIR sensor to detect movement, buzzes a buzzer

// more info here: http://blog.makezine.com/projects/pir-sensor-arduino-alarm/

// email me, John Park, at jp@jpixl.net

// based upon:

// PIR sensor tester by Limor Fried of Adafruit

// tone code by michael@thegrebs.com



 

int ledPin = 13;                // choose the pin for the LED

int inputPin = 2;               // choose the input pin (for PIR sensor)

int pirState = LOW;             // we start, assuming no motion detected

int val = 0;                    // variable for reading the pin status

int pinSpeaker = 10;           //Set up a speaker on a PWM pin (digital 9, 10, or 11)



void setup() {

  pinMode(ledPin, OUTPUT);      // declare LED as output

  pinMode(inputPin, INPUT);     // declare sensor as input

  pinMode(pinSpeaker, OUTPUT);

  Serial.begin(9600);

}



void loop(){

  val = digitalRead(inputPin);  // read input value

  if (val == HIGH) {            // check if the input is HIGH

    digitalWrite(ledPin, HIGH);  // turn LED ON

    playTone(300, 160);

    delay(150);



    

    if (pirState == LOW) {

      // we have just turned on

      Serial.println("Motion detected!");

      // We only want to print on the output change, not state

      pirState = HIGH;

    }

  } else {

      digitalWrite(ledPin, LOW); // turn LED OFF

      playTone(0, 0);

      delay(300);    

      if (pirState == HIGH){

      // we have just turned of

      Serial.println("Motion ended!");

      // We only want to print on the output change, not state

      pirState = LOW;

    }

  }

}

// duration in mSecs, frequency in hertz

void playTone(long duration, int freq) {

    duration *= 1000;

    int period = (1.0 / freq) * 1000000;

    long elapsed_time = 0;

    while (elapsed_time < duration) {

        digitalWrite(pinSpeaker,HIGH);

        delayMicroseconds(period / 2);

        digitalWrite(pinSpeaker, LOW);

        delayMicroseconds(period / 2);

        elapsed_time += (period);

    }

}