Diff: main.cpp

Revision:

2:f706efb3ea13

Parent:

1:4be688be4e0d

Child:

3:de6cc3ff5aaa

--- a/main.cpp	Sat Dec 20 12:03:10 2014 +0000
+++ b/main.cpp	Sat Mar 21 23:47:23 2015 +0000
@@ -1,6 +1,7 @@
-// In this example an MQTT client is created.
-// It is publishing parameters measured by a DHT11 sensor
-// UIPEthernet library is used to drive the ENC28J60 board
+// In this project an MQTT client is created.
+// It is publishing parameters measured by a DHT11 sensor.
+// Ethernet connection is assured via an ENC28J60 module.
+
 #include <mbed.h>
 #include <UIPEthernet.h>
 #include <UIPClient.h>
@@ -11,50 +12,62 @@
 // Do not change the name! It is used within the UIPEthernet library.
 // Adapt the SPI pin names to your mbed platform/board if not present yet.
 #if defined(TARGET_LPC1768)
-UIPEthernetClass UIPEthernet(p11, p12, p13, p8);        // mosi, miso, sck, cs
-DHT11   dht11(p6);
-#elif defined (TARGET_NUCLEO_F103RB)
-UIPEthernetClass UIPEthernet(PB_5, PB_4, PB_3, PB_6);   // mosi, miso, sck, cs
-DHT11   dht11(PC_14);
+UIPEthernetClass    UIPEthernet(p11, p12, p13, p8);         // mosi, miso, sck, cs
+DHT11               dht11(p6);
+#elif defined(TARGET_NUCLEO_F103RB)
+UIPEthernetClass    UIPEthernet(PB_5, PB_4, PB_3, PB_6);    // mosi, miso, sck, cs
+DHT11               dht11(PC_14);
 #endif
 
 // Make sure that the MAC number is unique within the connected network.
-const uint8_t       MY_MAC[6] = {0x00,0x01,0x02,0x03,0x04,0x05};
+const uint8_t       MY_MAC[6] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 };
+// This client is using a static IP address. Make sure DHCP is disabled on your router/modem.
 // IP address must be unique and compatible with your network too. Change as appropriate.
-const IPAddress     MY_IP(192,168,1,181);
+const IPAddress     MY_IP(192, 168, 1, 181);
 char                message_buff[100];
 void                onMessage(char* topic, uint8_t* payload, unsigned int length);
-IPAddress           serverIP(192,168,1,30);  // MQTT server (e.g. 'mosquitto' running on a Raspberry Pi or Ubuntu)
+// In case your MQTT broker has different IP adress modify the following definition accordingly.
+IPAddress           serverIP(192, 168, 1, 30);  // MQTT broker (e.g. 'Mosquitto' running on a Raspberry Pi or Linux device)
+// The MQTT broker is like a post office distributing messages received from publishing clients to all subscribers (clients).  
+// So the messages published by this client will be sent via the broker to all clients which subscribed to such messages.
+// This way also this client will receive all subscribed messages from other clients, but via the broker.
 EthernetClient      ethernetClient;
 void                onMqttMessage(char* topic, uint8_t* payload, unsigned int length);
 MQTTClient          mqttClient(serverIP, 1883, onMqttMessage, ethernetClient);
-const int           PERIOD = 10;             // seconds
-
+const int           PERIOD = 10;    // period for publishing the messages (in seconds)
 Serial              pc(USBTX, USBRX);
 
-int main()
-{
+/**
+ * @brief   Main
+ * @note
+ * @param
+ * @retval
+ */
+int main(void) {
     const int   MAX_COUNT = 5;
     int         i = 0;
     bool        connected = false;
     time_t      t = 0;
     time_t      lastTime = 0;
-    
+
     // initialize the ethernet device
     UIPEthernet.begin(MY_MAC, MY_IP);
-    pc.printf("Connecting to MQTT server ..\r\n");
-    do {
+    pc.printf("Connecting to MQTT broker ..\r\n");
+    do
+    {
         wait(1.0);
         connected = mqttClient.connect("myMqttClient");
     } while(!connected && (i < MAX_COUNT));
 
     if(connected) {
-        pc.printf("MQTT Server connected.\r\n");
-        mqttClient.subscribe("rt_clock");
-        pc.printf("Subscribed to: ");
-        pc.printf("rt_clock\r\n");
-    } else {
-        pc.printf("Failed to connect to MQTT server.\r\n");
+        pc.printf("MQTT broker connected.\r\n");
+        // The client can subscribe to as many MQTT messages as you like.
+        mqttClient.subscribe("outdoor/gasmeter"); 
+        mqttClient.subscribe("livingroom/temperature");
+        mqttClient.subscribe("boiler/outlet/temperature");
+    }
+    else {
+        pc.printf("Failed to connect to MQTT broker.\r\n");
     }
 
     while(1) {
@@ -64,17 +77,20 @@
             if(connected) {
                 pc.printf("---------------------\r\n");
                 pc.printf("%ds:\r\n", t);
+
                 int state = dht11.readData();
                 if(state == DHT11::OK) {
-                    float hum = dht11.readHumidity();
+                    float   hum = dht11.readHumidity();
                     sprintf(message_buff, "%4.1f", hum);
                     pc.printf("  hum = %s%%\r\n", message_buff);
                     mqttClient.publish("outdoor/humidity", message_buff);
-                    float temp = dht11.readTemperature();
+
+                    float   temp = dht11.readTemperature();
                     sprintf(message_buff, "%5.1f", temp);
                     pc.printf("  temp = %s'C\r\n", message_buff);
                     mqttClient.publish("outdoor/temperature", message_buff);
-                    float dewPoint = temp - (100 - hum)/5.0;
+
+                    float   dewPoint = temp - (100 - hum) / 5.0;
                     sprintf(message_buff, "%5.1f", dewPoint);
                     pc.printf("  dew point = %s'C\r\n", message_buff);
                     mqttClient.publish("outdoor/dewpoint", message_buff);
@@ -83,12 +99,20 @@
                     pc.printf("  DHT11 error: %d\r\n", state);
             }
         }
+
         mqttClient.loop();  // MQTT client loop processing
     }
 }
 
-void onMqttMessage(char* topic, uint8_t* payload, unsigned int length)
-{
+/**
+ * @brief   Called on new MQTT message arrival
+ * @note    
+ * @param   topic:      The topic of the new message
+ *          payload:    The payload of the new message
+ *          length:     Payload's length
+ * @retval
+ */
+void onMqttMessage(char* topic, uint8_t* payload, unsigned int length) {
     int i = 0;
 
     pc.printf("Message arrived:\r\n");
@@ -103,7 +127,3 @@
     message_buff[i] = '\0';
     pc.printf("  Payload: %s\r\n", message_buff);
 }
-
-
-
-