diff --git a/code/espurna/config/all.h b/code/espurna/config/all.h
index 15ba43e2..90d60d15 100644
--- a/code/espurna/config/all.h
+++ b/code/espurna/config/all.h
@@ -1,9 +1,9 @@
 #include "version.h"
 #include "arduino.h"
 #include "hardware.h"
+#include "prototypes.h"
 #include "general.h"
 #include "sensors.h"
-#include "prototypes.h"
 
 #ifdef USE_CORE_VERSION_H
 #include "core_version.h"
diff --git a/code/espurna/config/general.h b/code/espurna/config/general.h
index b0e45134..ddd65dfe 100644
--- a/code/espurna/config/general.h
+++ b/code/espurna/config/general.h
@@ -659,28 +659,6 @@ PROGMEM const char* const custom_reset_string[] = {
 
 #endif
 
-// -----------------------------------------------------------------------------
-// I2C
-// -----------------------------------------------------------------------------
-
-#ifndef I2C_SUPPORT
-#define I2C_SUPPORT             1           // I2C enabled (1.98Kb)
-#endif
-
-#define I2C_USE_BRZO            0           // Use brzo_i2c library or standard Wire
-
-#ifndef I2C_SDA_PIN
-#define I2C_SDA_PIN             SDA         // SDA GPIO (Sonoff => 4)
-#endif
-
-#ifndef I2C_SCL_PIN
-#define I2C_SCL_PIN             SCL         // SCL GPIO (Sonoff => 14)
-#endif
-
-#define I2C_CLOCK_STRETCH_TIME  200         // BRZO clock stretch time
-#define I2C_SCL_FREQUENCY       1000        // BRZO SCL frequency
-#define I2C_CLEAR_BUS           0           // Clear I2C bus at boot
-
 // -----------------------------------------------------------------------------
 // DOMOTICZ
 // -----------------------------------------------------------------------------
diff --git a/code/espurna/config/prototypes.h b/code/espurna/config/prototypes.h
index 08e6befd..a3018c43 100644
--- a/code/espurna/config/prototypes.h
+++ b/code/espurna/config/prototypes.h
@@ -48,21 +48,28 @@ template<typename T> bool setSetting(const String& key, unsigned int index, T va
 template<typename T> String getSetting(const String& key, T defaultValue);
 template<typename T> String getSetting(const String& key, unsigned int index, T defaultValue);
 
+// -----------------------------------------------------------------------------
+// I2C
+// -----------------------------------------------------------------------------
+unsigned char i2cFindFirst(size_t size, unsigned char * addresses);
+
+// -----------------------------------------------------------------------------
+// Debug
+// -----------------------------------------------------------------------------
+void debugSend(const char * format, ...);
+void debugSend_P(PGM_P format, ...);
+
 // -----------------------------------------------------------------------------
 // Domoticz
 // -----------------------------------------------------------------------------
-#if DOMOTICZ_SUPPORT
 template<typename T> void domoticzSend(const char * key, T value);
 template<typename T> void domoticzSend(const char * key, T nvalue, const char * svalue);
-#endif
 
 // -----------------------------------------------------------------------------
 // InfluxDB
 // -----------------------------------------------------------------------------
-#if INFLUXDB_SUPPORT
 template<typename T> bool idbSend(const char * topic, T payload);
 template<typename T> bool idbSend(const char * topic, unsigned char id, T payload);
-#endif
 
 // -----------------------------------------------------------------------------
 // Light
diff --git a/code/espurna/config/sensors.h b/code/espurna/config/sensors.h
index 9c094b26..fa0e6a35 100644
--- a/code/espurna/config/sensors.h
+++ b/code/espurna/config/sensors.h
@@ -97,7 +97,7 @@
 #endif
 
 #ifndef BMX280_ADDRESS
-#define BMX280_ADDRESS                  0
+#define BMX280_ADDRESS                  0x00    // 0x00 means auto
 #endif
 
 #define BMX280_MODE                     1       // 1 for forced mode, 3 for normal mode
@@ -105,6 +105,11 @@
 #define BMX280_HUMIDITY                 1       // Oversampling for humidity (set to 0 to disable magnitude, only for BME280)
 #define BMX280_PRESSURE                 1       // Oversampling for pressure (set to 0 to disable magnitude)
 
+#if BMX280_SUPPORT
+#undef I2C_SUPPORT
+#define I2C_SUPPORT                     1
+#endif
+
 //--------------------------------------------------------------------------------
 // Dallas OneWire temperature sensors
 // Enable support by passing DALLAS_SUPPORT=1 build flag
@@ -185,7 +190,12 @@
 #define EMON_ADC121_SUPPORT             0       // Do not build support by default
 #endif
 
-#define EMON_ADC121_I2C_ADDRESS         0x50    // I2C address of the ADC121
+#define EMON_ADC121_I2C_ADDRESS         0x00    // 0x00 means auto
+
+#if EMON_ADC121_SUPPORT
+#undef I2C_SUPPORT
+#define I2C_SUPPORT                     1
+#endif
 
 //--------------------------------------------------------------------------------
 // Energy Monitor based on ADS1X15
@@ -196,11 +206,16 @@
 #define EMON_ADS1X15_SUPPORT            0       // Do not build support by default
 #endif
 
-#define EMON_ADS1X15_I2C_ADDRESS        0x48    // I2C address of the ADS1115
+#define EMON_ADS1X15_I2C_ADDRESS        0x00    // 0x00 means auto
 #define EMON_ADS1X15_TYPE               ADS1X15_CHIP_ADS1115
 #define EMON_ADS1X15_GAIN               ADS1X15_REG_CONFIG_PGA_4_096V
 #define EMON_ADS1X15_MASK               0x0F    // A0=1 A1=2 A2=4 A4=8
 
+#if EMON_ADS1X15_SUPPORT
+#undef I2C_SUPPORT
+#define I2C_SUPPORT                     1
+#endif
+
 //--------------------------------------------------------------------------------
 // Energy Monitor based on interval analog GPIO
 // Enable support by passing EMON_ANALOG_SUPPORT=1 build flag
@@ -272,9 +287,36 @@
 #endif
 
 #ifndef SI7021_ADDRESS
-#define SI7021_ADDRESS                  0x40
+#define SI7021_ADDRESS                  0x00    // 0x00 means auto
+#endif
+
+#if SI7021_SUPPORT
+#undef I2C_SUPPORT
+#define I2C_SUPPORT                     1
 #endif
 
+// -----------------------------------------------------------------------------
+// I2C
+// -----------------------------------------------------------------------------
+
+#ifndef I2C_SUPPORT
+#define I2C_SUPPORT                     0       // I2C enabled (1.98Kb)
+#endif
+
+#define I2C_USE_BRZO                    0       // Use brzo_i2c library or standard Wire
+
+#ifndef I2C_SDA_PIN
+#define I2C_SDA_PIN                     SDA     // SDA GPIO (Sonoff => 4)
+#endif
+
+#ifndef I2C_SCL_PIN
+#define I2C_SCL_PIN                     SCL     // SCL GPIO (Sonoff => 14)
+#endif
+
+#define I2C_CLOCK_STRETCH_TIME          200     // BRZO clock stretch time
+#define I2C_SCL_FREQUENCY               1000    // BRZO SCL frequency
+#define I2C_CLEAR_BUS                   0       // Clear I2C bus at boot
+
 //--------------------------------------------------------------------------------
 // Internal power monitor
 // Enable support by passing ADC_VCC_ENABLED=1 build flag
@@ -293,11 +335,6 @@
 // Class loading
 //--------------------------------------------------------------------------------
 
-// Embarrasing...
-unsigned char i2cFindFirst(size_t size, unsigned char * addresses);
-void debugSend(const char * format, ...);
-void debugSend_P(PGM_P format, ...);
-
 #include "sensors/BaseSensor.h"
 
 #if ANALOG_SUPPORT