fix broken header

BH1750.h

@@ -36,6 +36,9 @@
 // Reset data register value - not accepted in POWER_DOWN mode
 #define BH1750_RESET 0x07
 
+// Default MTreg value
+#define BH1750_DEFAULT_MTREG 69
+
 class BH1750 {
 
   public:
@@ -60,15 +63,25 @@ class BH1750 {
     BH1750(byte addr = 0x23);
     bool begin(Mode mode = CONTINUOUS_HIGH_RES_MODE);
     bool configure(Mode mode);
+    bool setMTreg(byte MTreg);
     #ifndef BH1750_FLOAT
-    uint16_t readLightLevel(bool maxWait = false);
+    int32_t readLightLevel(bool maxWait = false, bool hundredth = false);
     #endif
     #ifdef BH1750_FLOAT
     float readLightLevel(bool maxWait = false);
     #endif
 
   private:
-    int BH1750_I2CADDR;
+    byte BH1750_I2CADDR;
+    byte BH1750_MTreg = (byte)BH1750_DEFAULT_MTREG;
+    // Correction factor used to calculate lux. Typical value is 1.2 but can range from 0.96 to 1.44.
+    // See data sheet (p.2, Measurement Accuracy) for more information.
+    #ifndef BH1750_FLOAT
+    const uint8_t BH1750_CONV_FACTOR = 12;
+    #endif
+    #ifdef BH1750_FLOAT
+    const float BH1750_CONV_FACTOR = 1.2;
+    #endif
     Mode BH1750_MODE = UNCONFIGURED;
 
 };

README.md

@@ -46,13 +46,14 @@ Usually you will get an integer value which represent the lux equivalent.
 
 The sensor returns a 16 bit unsigned integer. Therefore the maximum value is limited in general. 
 The standard conversion between the so called 'counts' to lux is 1/1.2, that means you get a smaller value.
-If a error occurs you will get a positive value closely to the max.
-  - 65534 (65535-1) no valid data was transmitted from the sensor
-  - 65533 (65535-2) device is not configured
-If you use the float, you get:
-If a error occurs you will get a negative value.
+As we use signed integer or float, if an error occurs you will get a negative value.
   - -1 no valid data was transmitted from the sensor
   - -2 device is not configured
+  
+As the sensor counts impact of light in a specific time frame you could change this time frame. 
+This is needed if you use an overlay windows or compensate environmental influence like darkness.
+This time frame is defined by a register which is called MTreg. Therefore you could choose a value between 32 and 254.
+The default value is 69; keep in mind that the measurement time is changed accordingly.
 
 The datasheet for the BH1750 chip can be obtained [here](http://www.elechouse.com/elechouse/images/product/Digital%20light%20Sensor/bh1750fvi-e.pdf)
 
@@ -146,12 +147,12 @@ void loop() {
 Moving the sensor to face more light results in the lux measurements increasing.
 ```
 BH1750 Test
-Light: 70 lx
-Light: 70 lx
-Light: 59 lx
-Light: 328 lx
-Light: 333 lx
-Light: 335 lx
-Light: 332 lx
+Light: 70.0 lx
+Light: 70.0 lx
+Light: 59.0 lx
+Light: 328.0 lx
+Light: 333.0 lx
+Light: 335.0 lx
+Light: 332.0 lx
 ```
 There are more examples in the examples directory.

examples/BH1750autoadjust/BH1750autoadjust.ino

@@ -0,0 +1,52 @@
+/*
+
+  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);
+
+  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);
+
+}

keywords.txt

@@ -14,9 +14,9 @@ BH1750	KEYWORD1
 
 begin	KEYWORD2
 configure	KEYWORD2
+setMTreg	KEYWORD2
 readLightLevel	KEYWORD2
 
-
 #######################################
 # Instances (KEYWORD2)
 #######################################
@@ -31,3 +31,4 @@ BH1750_CONTINUOUS_LOW_RES_MODE	LITERAL1
 BH1750_ONE_TIME_HIGH_RES_MODE	LITERAL1
 BH1750_ONE_TIME_HIGH_RES_MODE_2	LITERAL1
 BH1750_ONE_TIME_LOW_RES_MODE	LITERAL1
+BH1750_DEFAULT_MTREG	LITERAL1