Arduino无法根据模拟输入变量点亮LED

Question

I cant make arduino output high using a variable for example I declare this above my function

int pin;  
pinMode(A1, OUTPUT);

Main function

 if(id ==2){
 pin = A1;
 ledlight();}
 if(id==3){
  pin  =A2; 
 ledlight();} 

And after that i call this to light up my LED

  void ledlight(){
  if (temp < 27 ) {

  digitalWrite(pin, HIGH);  
   }
   }

Surprisingly the led does not light up, when i replace it with A1 the led lighted up ,what is the problem ?

Answer 1

use Serial to debug your program

output every variable(id temp pin), then you will find out the answer

here is the example of Serial

void setup() {
  pinMode(2, INPUT);
  pinMode(3, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(3, digitalRead(2));
  int n = analogRead(A0);
  Serial.print("analogRead from A0:");
  Serial.print(n);
  Serial.print("\n");
  delay(100);
}