[Help] BH1750 light intensity sensor did not work with Timer1

Other Hardware Sensors
2

I just found a solution, I use a check variable , when timer is up, the variable will raise and it's condition for loop function read data from BH1750. But, I dont really like it. My code following.

#include <Wire.h>
#include <TimerOne.h>

#define BH175_ADDRESS         0x23
byte buff[2];
boolean flag = false;

void setup()   {                
  // initialize the digital pin as an output:

  Timer1.initialize(2000000);         // initialize timer1, and set a 1/2 second period
  Timer1.attachInterrupt(callback);  // attaches callback() as a timer overflow interrupt
  Serial.begin(9600);
  Serial.println("Testing");
}

// the loop() method runs over and over again,
// as long as the Arduino has power

void loop()                     
{
  //callback();
  if(flag)
  {
    Serial.println("check");
    BH1750_Init(BH175_ADDRESS);
    if(BH1750_Read(BH175_ADDRESS) != 2)
    {
      //Light sensor has problem!
      Serial.println("Light sensor has problem!");
      return;
    }
    int lightIntensity = ((buff[0]<<8)|buff[1])/1.2;
    Serial.println(lightIntensity);
    flag = false;
  }
}

void callback()
{
  flag = true;
}

int BH1750_Read(int address) //
{
  int count = 0;
  Wire.beginTransmission(address);
  Wire.requestFrom(address, 2);
  while(Wire.available()) //
  {
    buff[count] = Wire.read();  // receive one byte
    count++;
  }
  Wire.endTransmission();  
  return count;
}

void BH1750_Init(int address) 
{
  Wire.beginTransmission(address);
  Wire.write(0x10);//1lx reolution 120ms
  Wire.endTransmission();
}