I’ve recently bought a few sensor modules for my planned revamp of my RF24 network. I also found this website which seems to be a guy who has been playing with many of the same sensors!

First off we have the BH1750FVI light intensity sensor. I connected to a Nano like so:

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BH1750 - Nano3:
VCC    - 3.3v
GND    - GND
SCL    - SCL (a5)
SDA    - SDA (a4)
ADD    - Not connected

The ebay listing says 3-5v power, and I must say I connected it to 5v just fine, but better go with 3.3v for safety.

I found that the readings were approximately:

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2000 = sunny
200 = indoors day
100 = indoors night
0 = pitch black

The library I used was from Github and my code is below:

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#include <Wire.h>
#include <BH1750.h>
BH1750 lightMeter;
int lux = 0;
int last_reading = 0;
void setup()
{
    Serial.begin(9600);
    lightMeter.begin();
}
void loop()
{
    lux = lightMeter.readLightLevel();
    if (lux != last_reading)
    {
        Serial.println(lux);
        last_reading = lux;
    }
}