尽管造书去做的。但还是有莫名的成就感

从串口显示出，电压变化，

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


void loop() {
  // put your main code here, to run repeatedly:
  int val=analogRead(A0);
  Serial.println(val);
  delay(500);
}