hello_world.ino

/*AWS Iot Core

This example needs https://github.com/esp8266/arduino-esp8266fs-plugin

It connects to AWS IoT server then:
- publishes "hello world" to the topic "outTopic" every two seconds
- subscribes to the topic "inTopic", printing out any messages
*/

#include "FS.h"
#include <ESP8266WiFi.h>
#include <PubSubClient.h> //https://www.arduinolibraries.info/libraries/pub-sub-client
#include <NTPClient.h> //https://www.arduinolibraries.info/libraries/ntp-client
#include <WiFiUdp.h>

// Update these with values suitable for your network.

const char* ssid = "XXXXXXXX";
const char* password = "XXXXXXX";

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

const char* AWS_endpoint = "XXXXXXXXXXX-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
//============================================================================
#define BUFFER_LEN 256
long lastMsg = 0;
char msg[BUFFER_LEN];
int value = 0;
byte mac[6];
char mac_Id[18];
//============================================================================

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("outTopic", "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);
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());

//===========================================================================
WiFi.macAddress(mac);
snprintf(mac_Id, sizeof(mac_Id), "%02x:%02x:%02x:%02x:%02x:%02x",
mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
Serial.print(mac_Id);
//============================================================================

}

void loop() {

if (!client.connected()) {
reconnect();
}
client.loop();

long now = millis();
if (now - lastMsg > 2000) {
lastMsg = now;
//============================================================================
String macIdStr = mac_Id;
uint8_t randomNumber = random(20, 50);
String randomString = String(random(0xffff), HEX);
snprintf (msg, BUFFER_LEN, "{\"mac_Id\" : \"%s\", \"random_number\" : %d, \"random_string\" : \"%s\"}", macIdStr.c_str(), randomNumber, randomString.c_str());

Serial.print("Publish message: ");
Serial.println(msg);
//mqttClient.publish("outTopic", msg);
client.publish("outTopic", msg);
//=============================================================================
Serial.print("Heap: "); Serial.println(ESP.getFreeHeap()); //Low heap can cause problems
}
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
}