adding the BH1750 from their downloads

BH1750/examples/BH1750test/BH1750test.ino

@@ -0,0 +1,54 @@
+/*
+
+  Example of BH1750 library usage.
+
+  This example initialises the BH1750 object using the default high resolution
+  continuous mode and then makes a light level reading every second.
+
+  Connection:
+
+    VCC -> 3V3 or 5V
+    GND -> GND
+    SCL -> SCL (A5 on Arduino Uno, Leonardo, etc or 21 on Mega and Due, on esp8266 free selectable)
+    SDA -> SDA (A4 on Arduino Uno, Leonardo, etc or 20 on Mega and Due, on esp8266 free selectable)
+    ADD -> (not connected) or GND
+
+  ADD pin is used to set sensor I2C address. If it has voltage greater or equal to
+  0.7VCC voltage (e.g. you've connected it to VCC) the sensor address will be
+  0x5C. In other case (if ADD voltage less than 0.7 * VCC) the sensor address will
+  be 0x23 (by default).
+
+*/
+
+
+#include <Wire.h>
+#include <BH1750.h>
+
+BH1750 lightMeter;
+
+
+void setup(){
+
+  Serial.begin(9600);
+
+  // Initialize the I2C bus (BH1750 library doesn't do this automatically)
+  Wire.begin();
+  // On esp8266 you can select SCL and SDA pins using Wire.begin(D4, D3);
+  // For Wemos / Lolin D1 Mini Pro and the Ambient Light shield use Wire.begin(D2, D1);
+
+  lightMeter.begin();
+
+  Serial.println(F("BH1750 Test begin"));
+
+}
+
+
+void loop() {
+
+  float lux = lightMeter.readLightLevel();
+  Serial.print("Light: ");
+  Serial.print(lux);
+  Serial.println(" lx");
+  delay(1000);
+
+}