Digital Light Sensor - BH1750FVI

BH1750FVI is a digital Ambient Light Sensor having I2C interface. This IC is the suitable for obtaining the ambient light data. It is possible to detect wide range at high resolution.

Description:

• Chip: BH1750FVI
• Power Supply: 3.3V - 5V
• Light Range：0 - 65535 lx(Lux)
• Sensor Built-in: 16 bit AD converter
• Size(L x W): Approx. 3.2cm x 1.5cm
• Direct digital output, bypassing the complex calculation, bypassing the calibration
• Close to the spectral characteristics of visual
• Widely used to 1-lux high precision measurement
• Standard NXP IIC communication

This is a BH1750 light intensity sensor breakout board with a 16 bit AD converter built-in which can directly output a digital signal, there is no need for complicated calculations. This is a more acurate and easier to use version of the simple LDR which only outputs a voltage that needs to be calculated in order to obtain meaningful data. With the BH1750 Light Sensor intensity can be directly measured by the luxmeter, without needing to make calculations. The data which is output by this sensor is directly output in Lux (Lx). When objects which are lighted in homogeneous get the 1 lx luminous flux in one square meter ,their light intensity is 1lx. Sometimes to take good advantage of the illuminant, you can add a reflector to the illuminant.So that there will be more luminous flux in some directions and it can increase the ilumination of the target surface. 

For example:

Night: 0.001--0.02; 
moonlightnight:0.02--0.3; 
cloudy indoor:5--50;
cloudy outdoor:50--500;
Sunny indoor:100--1000;
under the sunlight in summer afternoon: about 10*6 power; 
reading books for intensity of illumination:50--60;
home video standard intensity of illumination:1400.

Board Schematic

• J1 is interfacing connector
• U1 is voltage regulator which gives out 3V to board from 3.3-5V supply input
• Q1 is bidirectional data level translator for 5V to 3V level conversion
• D1 is unidirectional clock level translator for 5V to 3V level conversion
• Please note that the "addr" Pin is to assign a different I2C address to the sensor.

Arduino Sample Code

/*
 Sample code for the BH1750 Light sensor
  
 Connection:
  
 VCC-5v
 GND-GND
 SCL-SCL(analog pin 5)
 SDA-SDA(analog pin 4)
 ADD-NC
 */
 
 
#include <Wire.h> //BH1750 IIC Mode 
#include <math.h> 
int BH1750address = 0x23; //setting i2c address
 
byte buff[2];
void setup()
{
  Wire.begin();
  Serial.begin(57600);//init Serial rate
}
 
void loop()
{
  int i;
  uint16_t val=0;
  BH1750_Init(BH1750address);
  delay(200);
 
  if(2==BH1750_Read(BH1750address))
  {
    val=((buff[0]<<8)|buff[1])/1.2;
    Serial.print(val,DEC);     
    Serial.println("[lx]"); 
  }
  delay(150);
}
 
int BH1750_Read(int address) //
{
  int i=0;
  Wire.beginTransmission(address);
  Wire.requestFrom(address, 2);
  while(Wire.available()) //
  {
    buff[i] = Wire.receive();  // receive one byte
    i++;
  }
  Wire.endTransmission();  
  return i;
}
 
void BH1750_Init(int address) 
{
  Wire.beginTransmission(address);
  Wire.send(0x10);//1lx reolution 120ms
  Wire.endTransmission();
}