BH1750_Test.ino

#include <Wire.h>

#define BH1750_ADDR 0x23

int readBH1750(byte dev_addr) {
  Wire.beginTransmission(dev_addr);
  Wire.write(0x10);
  if (Wire.endTransmission() != 0) return -1;
  delay(200);
  Wire.requestFrom((int)dev_addr, 2);
  return (Wire.available() >= 2) ? (Wire.read()<<8)|Wire.read() : -1;
}

void setup() {
  Wire.begin();
  Serial.begin(9600);
}
 
void loop() {
  Serial.print("Light is ");
  Serial.print(readBH1750(BH1750_ADDR));
  Serial.println(" lx.");
  delay(1000);
}