#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);//设置LCD地址为0x27和0x3F为20字符和2行显示

#define LDR_PIN 2//光敏传感器引脚
int redPin= 7;
int greenPin = 6;
int bluePin = 5;
int Intensity =0;//定义此变量
#define AD5 A5//定义模拟口A5


void setup() {
  pinMode(LDR_PIN, INPUT);
  lcd.init();
  lcd.backlight();

  while (!Serial) {

  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);

}
}

void loop() {

Intensity = analogRead(AD5);  //读取模拟口AD5的值，存入Intensity变量
  Serial.print("Intensity = ");  //串口输出"Intensity = "
  Serial.println(Intensity);     //串口输出Intensity变量的值，并换行
  delay(500);     //延时500ms
if(Intensity>=800){
  digitalWrite(redPin,HIGH); 
  digitalWrite(greenPin,LOW); 
  digitalWrite(bluePin,LOW); 
  

  if（Intensity<800 && Intensity>=400){
  digitalWrite(redPin,LOW); 
  digitalWrite(greenPin,HIGH); 
  digitalWrite(bluePin,LOW); 
    

     if(Intensity>=100 && Intensity<400){
  digitalWrite(redPin,LOW); 
  digitalWrite(greenPin,LOW); 
  digitalWrite(bluePin,HIGH); 
    }
    else{
  digitalWrite(redPin,LOW); 
  digitalWrite(greenPin,LOW); 
  digitalWrite(bluePin,LOW);
    }
    }else{
  digitalWrite(redPin,LOW); 
  digitalWrite(greenPin,LOW); 
  digitalWrite(bluePin,LOW);
  }
}else{
  digitalWrite(redPin,LOW); 
  digitalWrite(greenPin,LOW); 
  digitalWrite(bluePin,LOW);
}
}

  lcd.setCursor(2, 0);
  lcd.print("Room: ");
  if (digitalRead(LDR_PIN) == LOW) {
    lcd.print("Light!");
  } else {
    lcd.print("Dark  ");
  }
  delay(100);
}



void setColor(int redValue, int greenValue, int blueValue) {
  analogWrite(redPin, redValue);
  analogWrite(greenPin, greenValue);
  analogWrite(bluePin, blueValue);
}