Diff: main.cpp

Revision:

6:b361643727ea

Parent:

5:b4c6bef81c0b

--- a/main.cpp	Sat Dec 11 16:28:50 2021 +0000
+++ b/main.cpp	Mon Dec 13 14:14:22 2021 +0000
@@ -1,5 +1,17 @@
+/*
+ * Program implements MQTT client on a NUCLEO-L476RG board
+ * using arm mbed-mqtt library and ESP-WROOM-02 WiFi modem.
+ *
+ * University of Belgrade - School of Electrical Engineering
+ * Department of Electronics
+ * Bulevar Kralja Aleksandra 73, 11120 Belgrade, Serbia
+ *
+ * November 2021.
+ *
+ */
+
+#include "mbed.h"
 #include "mb_pins.h"
-#include "mbed.h"
 #include "platform/mbed_thread.h"
 #include "MQTTClientMbedOs.h"
 
@@ -7,10 +19,7 @@
 #include "Adafruit_GFX_Config.h"
 #include "Adafruit_SSD1306.h"
 
-#include <string> 
-using namespace std;
 
-///////////////////////////////////////////////////////////////
 
 #define SMALL_WAIT_MS 10
 #define VOLTAGE_SCALER 3.3f
@@ -23,138 +32,83 @@
 #define OLED_HEIGHT_PX 64
 #define OLED_WIDTH_PX 128
 
-///////////////////////////////////////////////////////////////
-
+// Pointer to a WiFi network object:
+WiFiInterface *wifi;
+// Creating TCP socket:
 TCPSocket socket;
+// Creating MQTT client using the TCP socket;
 MQTTClient client(&socket);
+// Message handler:
 MQTT::Message message;
-WiFiInterface *wifi;
 
 I2C i2c_obj(MB_OLED_SDA, MB_OLED_SCL);
 Adafruit_SSD1306_I2c myOLED(i2c_obj, PB_5, I2C_ADD_MBED, OLED_HEIGHT_PX, OLED_WIDTH_PX);
 
 const char* topic_sub = "subpim";
 const char* topic_pub = "pubpim";
+// HiveMQ broker connectivity information:
 const char* hostname = "broker.hivemq.com";
 const int port = 1883;
 
-Timer t;
-AnalogIn pot1(MB_POT1);
-
-char buf[100];
-string s;
-
-string recv;
-string tran;
-
-bool oledInit = false;
-
-string chrToStr(char* a, int size){
-    string s = "";
-        for (int i = 0; i < size; i++) {
-            s = s + a[i];
-        }
-    return s;
-}
-
-void updateOLED()
-{
-    myOLED.clearDisplay();
-    myOLED.setTextCursor(0, 0);
-    myOLED.printf("Recv: %s\n", recv.c_str());
-    myOLED.printf("Tran: %s\n", tran.c_str());
-    myOLED.display(); 
-}
-
-void printMQTT()
-{
-    message.qos = MQTT::QOS0;
-    message.retained = false;
-    message.dup = false;
-    message.payload = (void*)buf;
-    //message.payloadlen = strlen(buf)+1;
-    message.payloadlen = strlen(buf);
-    client.publish(topic_pub, message);   
-}
-
-void sendValue(){
-    sprintf(buf, "V = %1.2f", pot1*VOLTAGE_SCALER);
-    s = chrToStr(buf, sizeof(buf));
-    tran = s;
-    printMQTT();
-}
-
-///////////////////////////////////////////////////////////////
 
 void messageArrived(MQTT::MessageData& md)
 {
-    MQTT::Message &message = md.message;
-    printf("Browser message: %.*s \n", message.payloadlen, (char*)message.payload);
-    
-    //sprintf(buf, "%.*s %d", message.payloadlen, (char*)message.payload, message.payloadlen);
-    //printMQTT();
-    
-    s = chrToStr((char*)message.payload, message.payloadlen);
-    
-    recv = s;
-    
-    //sprintf(buf, "%s", s.c_str());
-    //printMQTT();
-    
-    if(s == "start")
-    {
-        sendValue();
-        t.reset();
-        t.start();
-    }
-    else if(s == "stop")
-    {
-        t.stop();
-    }
-    else if(s == "oled")
-    {
-        oledInit = true;
-        myOLED.begin();
-        //myOLED.clearDisplay();
-        //myOLED.display();
-    }
+    MQTT::Message &msg = md.message;
+    printf("Browser message: %.*s \n", msg.payloadlen, (char*)msg.payload);
+    message.qos = MQTT::QOS0;
+    message.retained = false;
+    message.dup = false;
+    message.payload = (void*)msg.payload;
+    message.payloadlen = msg.payloadlen + 1;
+    client.publish(topic_pub, message);
+    myOLED.clearDisplay();
+    myOLED.setTextCursor(0, 0);
+    myOLED.printf("%.*s \n", msg.payloadlen, (char*)msg.payload);
+    myOLED.display(); 
     
 }
 
-///////////////////////////////////////////////////////////////
-
 int main()
 {
+    // Create a default network interface:
     wifi = WiFiInterface::get_default_instance();
+    if (!wifi) {
+        printf("ERROR: No WiFiInterface found.\n");
+        return -1;
+    }
     
-    printf("Connecting to %s \n",MBED_CONF_APP_WIFI_SSID);
+    // Connect to the network with the parameters specified in 'mbed_app.json':
+    printf("Connecting to %s... \n",MBED_CONF_APP_WIFI_SSID);
     int ret = wifi->connect(MBED_CONF_APP_WIFI_SSID, MBED_CONF_APP_WIFI_PASSWORD, NSAPI_SECURITY_WPA_WPA2);
-    //if(ret != 0){
-    //    printf("Greska u povezivanju");
-    //    return -1;
-    //}
-    printf("Connected\n");
+    if(ret != 0){
+        printf("\nConnection error: %d\n", ret);
+        return -1;
+    }
+    // Print out the information aquired:
+    printf("Connected to %s\n", MBED_CONF_APP_WIFI_SSID);
     
+    // Open TCP socket using WiFi network interface:
     socket.open(wifi);
+    
+    // Connect to the HiveMQ broker:
     socket.connect(hostname,port);
     
+    // Fill connect data with default values:
     MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
+    // Change only ID and protocol version:
     data.MQTTVersion = 3;
-    data.clientID.cstring = "pim-60";
+    data.clientID.cstring = "pim-09";
 
     client.connect(data);
     client.subscribe(topic_sub, MQTT::QOS0, messageArrived);
     
     i2c_obj.frequency(400000);
     
+    myOLED.begin();
+    myOLED.clearDisplay();
+    myOLED.display();
     while(1) {
-        if (t.read() > 10) {
-            sendValue();
-            t.reset();
-        }
         thread_sleep_for(SMALL_WAIT_MS);
-        if(oledInit)
-            updateOLED();
         client.yield(1000);
     }
 }