const int sensorPin = A0;
const float baselineTemp = 20.0;

void setup() {
  Serial.begin(9600); // open a serial port

  for (int pinNumber = 2; pinNumber < 5; pinNumber++) {
    pinMode(pinNumber, OUTPUT);
    digitalWrite(pinNumber, LOW);
  } // 关闭for循环的大括号
}

void loop() {
  int sensorVal = analogRead(sensorPin);
  Serial.print("Sensor Value: "); // 使用标准的双引号
  Serial.print(sensorVal);

  // convert the ADC reading to voltage
  float voltage = ((float)sensorVal / 1024.0) * 5.0; // 强制转换为 float 类型

  Serial.print(", Volts: "); // 使用标准的双引号
  Serial.print(voltage);
  Serial.print(", degrees C: "); // 使用标准的双引号
  
  // convert the voltage to temperature in degrees
  float temperature = (voltage - 0.5) * 100;
  Serial.println(temperature);

  if (temperature < baselineTemp) {
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  } 
  else if (temperature >= baselineTemp + 2 && temperature < baselineTemp + 4) {
    digitalWrite(2, HIGH);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  } 
  else if (temperature >= baselineTemp + 4 && temperature < baselineTemp + 6) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, LOW);
  } 
  else if (temperature >= baselineTemp + 6) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
  }

  delay(1000); // 延迟 1 秒，避免过于频繁的读数和LED控制
}