#include <Wire.h>
#include <math.h>
#include <Arduino.h>
//#include <MsTimer2.h>
#define SDA_PIN 21   
#define SCL_PIN 22 
int BH1750address = 0x23;//BH1750 I2C地址0x23  //ADDR="L" for this module

 
 
int BH1750() //BH1750设备操作
{
  unsigned char  buff[2];
  int i=0;
  double  val=0;
  //开始I2C读写操作
  Wire.beginTransmission(BH1750address);
  Wire.write(0x10);//1lx reolution 120ms//发送命令
  Wire.endTransmission();  
  
  delay(200);
  //读取数据
 // Wire.beginTransmission(BH1750address);
  //delay(120);
  
  Wire.requestFrom(BH1750address, 2);
 
  while(Wire.available()) 
  {
   // Serial.println("2");
    buff[i] = Wire.read();  // receive one byte
    i++;
  }
  Wire.endTransmission();
  if(2==i)
  {
   val=((buff[0]<<8)|buff[1])/1.2;
  }
  return val;

}