sketch_may19a.ino

#include "FS.h"
#include "ESP8266WiFi.h "
#include "PubSubClient.h "
#include "NTPClient.h "
#include "WiFiUdp.h "
#include <string.h>
#include <SoftwareSerial.h>
SoftwareSerial mySerial(D1,D2);

const char *ssid = "Abhay's Galaxy M30s";
const char *password = "  ";

WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "pool.ntp.org");

const char *AWS_endpoint = "a3apchnxj0-ats.iot.us-west-2.amazonaws.com"; //MQTT broker ip

void callback(char *topic, byte *payload, unsigned int length)
{
    Serial.print("Message arrived [");
    Serial.print(topic);
    Serial.print("] ");
    for (int i = 0; i< length; i++)
    {
        Serial.print((char)payload[i]);
    }
    Serial.println();
}
WiFiClientSecure espClient;
PubSubClient client(AWS_endpoint, 8883, callback, espClient); //set MQTT port number to 8883 as per //standard
long lastMsg = 0;
char msg[50];
int value = 0;

void setup_wifi()
{

    delay(10);
    // We start by connecting to a WiFi network
    espClient.setBufferSizes(512, 512);
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);

    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED)
    {
        delay(500);
        Serial.print(".");
    }

    Serial.println("");
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());

    timeClient.begin();
    while (!timeClient.update())
    {
        timeClient.forceUpdate();
    }

    espClient.setX509Time(timeClient.getEpochTime());
}

void reconnect()
{
    // Loop until we're reconnected
    while (!client.connected())
    {
        Serial.print("Attempting MQTT connection...");
        // Attempt to connect
        if (client.connect("ESPthing"))
        {
            Serial.println("connected");
            // Once connected, publish an announcement...
            client.publish("ESP8266_Smart_door_log", "hello world");
            // ... and resubscribe
            client.subscribe("inTopic");
        }
        else
        {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 5 seconds");

            char buf[256];
            espClient.getLastSSLError(buf, 256);
            Serial.print("WiFiClientSecure SSL error: ");
            Serial.println(buf);

            // Wait 5 seconds before retrying
            delay(5000);
        }
    }
}

void setup()
{

    Serial.begin(115200);
    mySerial.begin(9600);
    Serial.setDebugOutput(true);
    // initialize digital pin LED_BUILTIN as an output.
    pinMode(LED_BUILTIN, OUTPUT);
    setup_wifi();
    delay(1000);
    if (!SPIFFS.begin())
    {
        Serial.println("Failed to mount file system");
        return;
    }

    Serial.print("Heap: ");
    Serial.println(ESP.getFreeHeap());

    // Load certificate file
    File cert = SPIFFS.open("/cert.der", "r"); //replace cert.crt eith your uploaded file name
    if (!cert)
    {
        Serial.println("Failed to open cert file");
    }
    else
        Serial.println("Success to open cert file");

    delay(1000);
    if (espClient.loadCertificate(cert))
        Serial.println("cert loaded");
    else
        Serial.println("cert not loaded");

    // Load private key file
    File private_key = SPIFFS.open("/private.der", "r"); //replace private eith your uploaded file name
    if (!private_key)
    {
        Serial.println("Failed to open private cert file");
    }
    else
        Serial.println("Success to open private cert file");

    delay(1000);

    if (espClient.loadPrivateKey(private_key))
        Serial.println("private key loaded");
    else
        Serial.println("private key not loaded");

    // Load CA file
    File ca = SPIFFS.open("/ca.der", "r"); //replace ca eith your uploaded file name
    if (!ca)
    {
        Serial.println("Failed to open ca ");
    }
    else
        Serial.println("Success to open ca");

    delay(1000);

    if (espClient.loadCACert(ca))
        Serial.println("ca loaded");
    else
        Serial.println("ca failed");

    Serial.print("Heap: ");
    Serial.println(ESP.getFreeHeap());
}

void loop()
{
  
 String msg1 = mySerial.readStringUntil('\r');
    Serial.println(msg1);
    if (!client.connected()) {
      reconnect();
      }
client.loop();


Serial.print("Publish message: ");

snprintf (msg, 75, "{\"message\": \"%s\"}", msg1.c_str());
Serial.println(msg1);
//if(msg1!="" or  sizeof(msg1)!=1 )
if(strlen(msg1.c_str())/sizeof('a')>2 )
{
  client.publish("outTopic", msg);  
}

Serial.print("Heap: "); 
Serial.println(ESP.getFreeHeap()); //Low heap can cause problems                  // wait for a second

digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(100); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(100); // wait for a second
}