用Arduino写一段代码，仅仅具有一块Arduino UNO板、红绿两个LED灯，一个LM35测温模块。要求，气温低于-20摄氏度，红灯闪烁。气温大于等于-20摄氏度小于0度红灯常亮。气温等于0摄氏度红绿灯交替闪烁，气温大于0度小于等于19.5摄氏度红绿灯均常亮，气温大于19.5摄氏度小于等于31摄氏度绿灯常亮，气温大于31摄氏度绿灯闪烁。

以下是Arduino代码示例：

int redLed = 13;
int greenLed = 12;
int temperaturePin = A0;

void setup() {
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
}

void loop() {
  float temperature = analogRead(temperaturePin) * 0.4887;
  if (temperature < -20) {
    digitalWrite(redLed, HIGH);
    delay(500);
    digitalWrite(redLed, LOW);
    delay(500);
  }
  else if (temperature >= -20 && temperature < 0) {
    digitalWrite(redLed, HIGH);
  }
  else if (temperature == 0) {
    digitalWrite(redLed, HIGH);
    delay(500);
    digitalWrite(redLed, LOW);
    digitalWrite(greenLed, HIGH);
    delay(500);
    digitalWrite(greenLed, LOW);
  }
  else if (temperature > 0 && temperature <= 19.5) {
    digitalWrite(redLed, HIGH);
    digitalWrite(greenLed, HIGH);
  }
  else if (temperature > 19.5 && temperature <= 31) {
    digitalWrite(greenLed, HIGH);
  }
  else if (temperature > 31) {
    digitalWrite(greenLed, HIGH);
    delay(500);
    digitalWrite(greenLed, LOW);
    delay(500);
  }
}

请注意：上面的代码假设温度读数的范围在0到1023之间，因此读数必须乘以0.4887以获得摄氏温度。请根据实际情况进行调整。