void setup() {
  Serial.begin(9600);
//继电器控制引脚
pinMode(13, OUTPUT);

}


void loop() {

  int infrared = digitalRead(8);

  if(infrared == 1){//感应到有人
  digitalWrite(13,1);//灯亮
  }else{
  digitalWrite(13,0);  
  }
  Serial.println(infrared);
  delay(300);
}

//hx711.h推荐称重库