Fix MCP9808 + new features (#484)

Author: pilotak

README.md

@@ -1006,6 +1006,16 @@ Each sensor class may expose additional methods.
 	void sendSMS(const char* text);
 ~~~
 
+* SensorMCP9808
+~~~c
+    // set I2C address (default: 0x18)
+    void setI2CAddress(uint8_t i2caddress);
+    // set temperature resolution (default: 3)
+    void setResolution(uint8_t resolution);
+    // sleep sensor after measurment (default: true)
+    void setSleep(bool value);
+~~~ 
+
 ### OTA Configuration
 
 When `NODEMANAGER_OTA_CONFIGURATION` is set to ON the API presented above can be also called remotely through `SensorConfiguration`, which is automatically added to NodeManager. SensorConfiguration exposes by default child id 200 that can be used to interact with the service by sending `V_CUSTOM` type of messages and commands within the payload. For each `REQ` message, the node will respond with a `SET` message if successful.

sensors/SensorMCP9808.h

@@ -29,22 +29,44 @@ SensorMCP9808
 class SensorMCP9808: public Sensor {
 protected:
 	Adafruit_MCP9808* _mcp;
-	
+	uint8_t _i2caddress = MCP9808_I2CADDR_DEFAULT;
+	uint8_t _resolution = 3;
+	bool _sleep = true;
+
 public:
 	SensorMCP9808(uint8_t child_id = 0): Sensor(-1) {
 		_name = "MCP9808";
 		children.allocateBlocks(1);
 		new Child(this,FLOAT,nodeManager.getAvailableChildId(child_id),S_TEMP,V_TEMP,_name);
 	};
-
+	// set I2C address (default: 0x18)
+	void setI2CAddress(uint8_t i2caddress) {
+		_i2caddress = i2caddress;
+	};
+	// set temperature resolution (default: 3)
+	void setResolution(uint8_t resolution) {
+		_resolution = resolution;
+	};
+	// sleep sensor after measurment (default: true)
+	void setSleep(bool value){
+		_sleep = value;
+	}
 	// define what to do during setup
 	void onSetup() {
 		_mcp = new Adafruit_MCP9808();
+		_mcp->begin(_i2caddress);
+		_mcp->setResolution(_resolution);
 	};
-
 	// define what to do during loop
 	void onLoop(Child* child) {
+		// wake up
+		_mcp->shutdown_wake(false);
+		// sleep based on sample time
+		if(_sleep) nodeManager.sleepOrWait(33 << _resolution);
+		// get data
 		float temperature = _mcp->readTempC();
+		// sleep
+		if(_sleep) _mcp->shutdown_wake(true);
 		// convert it
 		temperature = nodeManager.celsiusToFahrenheit(temperature);
 		// store the value