Merge pull request #1647 from CraigMarkwardt/bmx280-second-sensor

sensors - allow a second BMX280 sensor

code/espurna/config/sensors.h

@@ -158,9 +158,14 @@
 #define BMX280_SUPPORT                  0
 #endif
 
-#ifndef BMX280_ADDRESS
-#define BMX280_ADDRESS                  0x00    // 0x00 means auto
+#ifndef BMX280_NUMBER
+#define BMX280_NUMBER                   2       // Number of sensors present. Either 1 or 2 allowed
 #endif
+#ifndef BMX280_ADDRESS
+#define BMX280_ADDRESS                  0x00    // 0x00 means auto (0x76 or 0x77 allowed) for sensor #0
+#endif                                          // If (BMX280_NUMBER == 2) and
+                                                //   (BMX280_ADDRESS == 0x00) then sensor #1 is auto-discovered
+                                                //   (BMX280_ADDRESS != 0x00) then sensor #1 is the unnamed address
 
 #define BMX280_MODE                     1       // 0 for sleep mode, 1 or 2 for forced mode, 3 for normal mode
 #define BMX280_STANDBY                  0       // 0 for 0.5ms, 1 for 62.5ms, 2 for 125ms

code/espurna/sensor.ino

@@ -484,6 +484,15 @@ void _sensorLoad() {
         BMX280Sensor * sensor = new BMX280Sensor();
         sensor->setAddress(BMX280_ADDRESS);
         _sensors.push_back(sensor);
+
+        #if (BMX280_NUMBER == 2)
+        // Up to two BME sensors allowed on one I2C bus
+        BMX280Sensor * sensor2 = new BMX280Sensor();
+	// For second sensor, if BMX280_ADDRESS is 0x00 then auto-discover
+	//   otherwise choose the other unnamed sensor address
+        sensor->setAddress( (BMX280_ADDRESS == 0x00) ? 0x00 : (0x76 + 0x77 - BMX280_ADDRESS));
+        _sensors.push_back(sensor2);
+        #endif
     }
     #endif