void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println("xin chao");
}

void loop() {
  // put your main code here, to run repeatedly:
  int sensorValue= analogRead(A0);
  Serial.println(sensorValue);
  delay(1000);// ngưng cả hệ thống
}