Pr/61 add I2C sensors BME280 and BH1750 (#64)

* changed user config

* added lightsensor module

* changed Pin Adresses

* Added I2C Lightsensor

Added the I2C Lightsensor and Switchted most Pins

* removed some debug to serial

removed some debug stuff was send to serial console

* Merge with Master

* Too much things for arduino uno

per default remove sensors for it

* Adding I2C Module function

Opens the Door on OpenMQTTGateway for "i2c Bus Modules/Sensors"

* Fixing BH1750 detection

Fixing the detection for a missing BH1750 Module

* Add libraries and define sensors depending on wiring type #63

ZsensorBH1750.ino

@@ -0,0 +1,150 @@
+/*  
+  OpenMQTTGateway Addon  - ESP8266 or Arduino program for home automation 
+
+   Act as a wifi or ethernet gateway between your 433mhz/infrared IR signal  and a MQTT broker 
+   Send and receiving command by MQTT
+ 
+   This is the Light Meter Addon:
+   - Measures ambient Light Intensity in Lux (lx), Foot Candela (ftcd) and Watt/m^2 (wattsm2)
+   - Required Hardware Module: BH1750
+
+   Connection Schemata:
+   --------------------
+
+   BH1750 ------> Arduino Uno ----------> ESP8266
+   ==============================================
+   Vcc ---------> 5V -------------------> Vu (5V)
+   GND ---------> GND ------------------> GND
+   SCL ---------> Pin A5 ---------------> D1
+   SDA ---------> Pin A4 ---------------> D2
+   ADD ---------> N/C (Not Connected) --> N/C (Not Connected)
+ 
+    Copyright: (c) Hans-Juergen Dinges
+  
+    This file is part of OpenMQTTGateway.
+    
+    OpenMQTTGateway is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenMQTTGateway is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef ZsensorBH1750
+#include "math.h" // Library for trig and exponential functions
+#include "Wire.h" // Library for communication with I2C / TWI devices
+#define bh1750_always true // if false when the current value for light Level (Lux) is the same as previous one don't send it by MQTT
+#define TimeBetweenReadingBH1750 30000
+
+/*----------------------------USER PARAMETERS-----------------------------*/
+/*-------------DEFINE YOUR MQTT PARAMETERS BELOW----------------*/
+#define LUX   "home/LIGHTtoMQTT/lux"
+#define FTCD  "home/LIGHTtoMQTT/ftcd"
+#define WATTSM2  "home/LIGHTtoMQTT/wattsm2"
+
+//Time used to wait for an interval before resending measured values
+unsigned long timebh1750 = 0;
+int BH1750_i2c_addr = 0x23; // Light Sensor I2C Address
+
+void setupZsensorBH1750()
+{
+  Wire.begin();
+  Wire.beginTransmission(BH1750_i2c_addr);
+  Wire.write(0x10);      // Set resolution to 1 Lux
+  Wire.endTransmission();
+  delay(300);
+}
+ 
+// void loop() 
+void MeasureLightIntensity()
+{
+  if (millis() > (timebh1750 + TimeBetweenReadingBH1750)) {//retriving value of Lux, FtCd and Wattsm2 from BH1750
+    timebh1750 = millis();
+    unsigned int i=0;
+    static float persistedll;
+    static float persistedlf;
+    static float persistedlw;
+    unsigned int Lux;
+    float FtCd;
+    float Wattsm2;
+
+    // Check if reads failed and exit early (to try again).
+    Wire.beginTransmission(BH1750_i2c_addr);
+    Wire.requestFrom(BH1750_i2c_addr, 2);
+    while(Wire.available()) //
+    {
+      i <<=8;
+      i|= Wire.read();  
+    }    
+    if (Wire.endTransmission() != 0 ) {
+      trc(F("Failed to read from LightSensor BH1750!"));
+    }else{
+
+      // Calculate the Values
+      Lux = i/1.2;  // Convert to Lux
+      FtCd = Lux/10.764;
+      Wattsm2 = Lux/683.0;
+
+      /*
+      Useful Information ;-)
+      lux (lx)                            # 1 lx = 1 lm/m² = 1 cd·sr·m⁻².
+      meter-candle (m-cd)                 # 1 m·cd = 1 lx = 1 lm/m² = 1 cd·sr·m⁻².
+      centimeter-candle (cm-sd)           # 1 m·cd = 1 lx = 1 lm/m² = 1 cd·sr·m⁻².
+      foot-candle (ft-c)                  # 
+      phot (ph)                           # 1 ph = 1 lm/cm² = 10,000 lm/m² - 10,000 lx = 10 klx
+      nox (nx)                            # 1 nox = 1 millilux
+      candela steradin/meter2(cd·sr·m⁻²)  # 1 lx = 1 lm/m² = 1 cd·sr·m⁻²
+      lumen/meter2 (lm·m⁻²)               # 1 lx = 1 lm/m² = 1 cd·sr·m⁻²
+      lumen/centimeter2 (lm·cm⁻²)         # 1 lm/cm² = 10,000 lx = 10,000 cd·sr·m⁻²
+      lumen/foot2 (lm·ft⁻²)               # (lm·ft⁻²)
+      watt/centimeter2 at 555nm  (W·cm⁻²) # 
+      */
+
+      // Generate Lux
+      if(Lux != persistedll || bh1750_always){
+        char lux[7];
+        sprintf(lux,"%d",Lux);
+        trc(F("Sending Lux to MQTT"));
+        trc(String(lux));
+        client.publish(LUX,lux);
+       }else{
+        trc(F("Same lux don't send it"));
+       }
+
+      // Generate FtCd
+      if(FtCd != persistedlf || bh1750_always){
+        char ftcd[7];
+        dtostrf(FtCd,4,2,ftcd);
+        trc(F("Sending FtCd to MQTT"));
+        trc(String(ftcd));
+        client.publish(FTCD,ftcd);
+      }else{
+        trc(F("Same ftcd don't send it"));
+      }
+
+      // Generate Watts/m2
+      if(Wattsm2 != persistedlw || bh1750_always){
+        char wattsm2[7];
+        dtostrf(Wattsm2,6,4,wattsm2);
+        trc(F("Sending Wattsm2 to MQTT"));
+        trc(String(wattsm2));
+        client.publish(WATTSM2,wattsm2);
+      }else{
+        trc(F("Same wattsm2 don't send it"));
+      }    
+
+    }
+    persistedll = Lux;
+    persistedlf = FtCd;
+    persistedlw = Wattsm2;
+  }
+}
+
+#endif