//模拟信号端口
int tempPin= 1;
//数字输出端口
int outpoint = 8;
//温度预定值
int temperature = 30;
void setup()
{
 Serial.begin(9600);
 pinMode(outpoint,OUTPUT);
}

void loop()
{

  int val;
  val =analogRead(tempPin);
  float cel=val/9.31;
  float farh=(cel*9)/5+32;
  Serial.print("TEMPERATURE in CELCIUS="); //摄氏温度
  Serial.print(cel); 
  Serial.print("*C");
  delay(5000);
  Serial.println();
  Serial.println("TEMPERATURE in FARHENHITE="); //华氏温度
  Serial.print(farh);
   Serial.print("*F");
  delay(5000); 
  Serial.println(); 

  if (cel>temperature) { 
    Serial.println("Its a hot day");
    //开启风扇
    digitalWrite(outpoint, HIGH);
  }
 else {
   Serial.println("Good day to be alive");
   //关闭风扇
   digitalWrite(outpoint, LOW);
  }
  delay(2000);
  Serial.println();

}

设计说明：参考https://mp-new.csdn.net/mp_blog/creation/editor/117532517