本項目BOM很簡單，只有PIR傳感器、蜂鳴器、LED和按鈕開關幾個元件，按下按鈕就可關閉蜂鳴聲。

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首先，將Arduino UNO開發板的 +5V、GND連接到面包板。

LED的陰極接地，陽極（長引腳）通過330 or 220歐姆的上拉電阻器連接到Arduino開發板的６＃引腳。

蜂鳴器的正極連接到Arduino板子的５＃引腳，負極引腳接GND。

按鈕開關的一個引腳通過1k歐姆電阻器接GND，另一引腳連接到Arduino的12引腳。

PIR運動傳感器的+Vcc、GND、output三個引腳分別連接于Arduino開發板的+Vcc、GND、pin 7引腳。

按照上述步驟連接正確后，接下來取Arduino IDE上傳代碼到。再檢查Serial Monitor的讀數，移動手掌到傳感器前面，LED將閃亮，蜂鳴器將會報警。

CODE;C/C++

// Declaring Pins
const int buzzerPin = 5;
const int ledPin = 6;
const int motionPin = 7;
const int buttonPin = 12;

// Setting Buzzer mode to False
boolean buzzer_mode = false;

// For LED
int ledState = LOW;
long previousMillis = 0;?
long interval = 100; ?// Interval at which LED blinks

void setup()
{
?//The Following are our output
?pinMode(ledPin,OUTPUT);
?pinMode(buzzerPin,OUTPUT);

?//Button is our Input
?pinMode(buttonPin, INPUT);
?
?// Wait before starting the alarm
?delay(5000);
}

void loop()
{
?// To chech whether the motion is detected or not
?if (digitalRead(motionPin)) {
? ?buzzer_mode = true;?
?}

?// If alarm mode is on,blink our LED
?if (buzzer_mode){
? ?unsigned long currentMillis = millis();
? ?if(currentMillis - previousMillis > interval) {
? ? ?previousMillis = currentMillis; ??
? ? ?if (ledState == LOW)
? ? ? ?ledState = HIGH;
? ? ?else
? ? ? ?ledState = LOW;
? ?// Switch the LED
? ?digitalWrite(ledPin, ledState);
? ?}
? ?tone(buzzerPin,1000);
?}

?// If alarm is off
?if (buzzer_mode == false) {
?
? ?// No tone & LED off
? ?noTone(buzzerPin); ?
? ?digitalWrite(ledPin, LOW);
?}

?// If our button is pressed Switch off ringing and Setup
?int button_state = digitalRead(buttonPin);
?if (button_state) {buzzer_mode = false;}
}

如果你覺得這個小制作有用處，就把它裝進小盒子里，固定到窗臺、門框和陽臺的不顯眼位置，一個屬于自己的防盜警報器就誕生了。
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