硬件：HC-SR501 人体红外感应模块，Arduinouno，杜邦线、led灯

连接：

效果：有人灯亮，没人灯灭

代码：

int PRI_sensor = 8;
int LED = 13;void setup() {
  pinMode(PRI_sensor,INPUT);
  pinMode(LED,OUTPUT);
  Serial.begin(9600);
}

void loop() {
 if(digitalRead(PRI_sensor) == HIGH)
 {
  Serial.println("someone here!");
  digitalWrite(LED,HIGH);
 }
 else
 {
  Serial.println("Nobody!");
  digitalWrite(LED,LOW);
 }
 delay(1000);
}