Added example for BH1750 lux sensor

libraries/BH1750/BH1750.h

@@ -0,0 +1,72 @@
+/*
+
+This is a library for the BH1750FVI Digital Light Sensor
+breakout board.
+
+The board uses I2C for communication. 2 pins are required to
+interface to the device.
+
+Datasheet:
+http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
+
+Written by Christopher Laws, March, 2013.
+
+*/
+
+#ifndef BH1750_h
+#define BH1750_h
+
+#if (ARDUINO >= 100)
+#include <Arduino.h>
+#else
+#include <WProgram.h>
+#endif
+#include "Wire.h"
+
+#define BH1750_DEBUG 0
+
+#define BH1750_I2CADDR 0x23
+
+// No active state
+#define BH1750_POWER_DOWN 0x00
+
+// Wating for measurment command
+#define BH1750_POWER_ON 0x01
+
+// Reset data register value - not accepted in POWER_DOWN mode
+#define BH1750_RESET 0x07
+
+// Start measurement at 1lx resolution. Measurement time is approx 120ms.
+#define BH1750_CONTINUOUS_HIGH_RES_MODE  0x10
+
+// Start measurement at 0.5lx resolution. Measurement time is approx 120ms.
+#define BH1750_CONTINUOUS_HIGH_RES_MODE_2  0x11
+
+// Start measurement at 4lx resolution. Measurement time is approx 16ms.
+#define BH1750_CONTINUOUS_LOW_RES_MODE  0x13
+
+// Start measurement at 1lx resolution. Measurement time is approx 120ms.
+// Device is automatically set to Power Down after measurement.
+#define BH1750_ONE_TIME_HIGH_RES_MODE  0x20
+
+// Start measurement at 0.5lx resolution. Measurement time is approx 120ms.
+// Device is automatically set to Power Down after measurement.
+#define BH1750_ONE_TIME_HIGH_RES_MODE_2  0x21
+
+// Start measurement at 1lx resolution. Measurement time is approx 120ms.
+// Device is automatically set to Power Down after measurement.
+#define BH1750_ONE_TIME_LOW_RES_MODE  0x23
+
+class BH1750 {
+ public:
+  BH1750();
+  void begin(uint8_t mode = BH1750_CONTINUOUS_HIGH_RES_MODE);
+  void configure(uint8_t mode);
+  uint16_t readLightLevel(void);
+
+ private:
+  void write8(uint8_t data);
+
+};
+
+#endif