MQTT Connection Guide

// ESP8266 — Secure MQTT connection (port 8883, TLS)
// Uses Let's Encrypt CA certificate — no file upload needed.
//
// ⚠ REQUIRES: ESP8266 Arduino Core ≥ 2.5.0 (BearSSL support)
// Arduino IDE → Tools → Board → Boards Manager → "esp8266 by ESP8266 Community" → update to 3.x

#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>
#include <BearSSLHelpers.h>
#include <PubSubClient.h>

// ── Wi-Fi ──────────────────────────────────────────
const char* ssid       = "YOUR_WIFI_SSID";
const char* wifiPass   = "YOUR_WIFI_PASSWORD";

// ── Virtuino Cloud MQTT ────────────────────────────
const char* mqttHost   = "cloud.virtuino.com";
const int   mqttPort   = 8883;
const char* mqttUser   = "vr-abcd1234";
const char* mqttPass   = "YOUR_MQTT_PASSWORD";
String      clientId;                           // built in setup(): prefix + chip ID

// ── Topics ─────────────────────────────────────────
// Built from mqttUser, so the account key is written only once
String deviceName  = "esp8266";
String topicTemp   = String(mqttUser) + "/in/device/"  + deviceName + "/temperature";  // device publishes → cloud
String topicRelay  = String(mqttUser) + "/out/device/" + deviceName + "/relay1";       // device subscribes ← cloud
String topicStatus = String(mqttUser) + "/in/device/"  + deviceName + "/LWT";          // reserved LWT topic (online / offline)

// ── ISRG Root X1 — Let's Encrypt CA Certificate ───
const char caCert[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
MIIFazCCA1OgAwIBAgIRAIIQz7DSQONZRGPgu2OCiwAwDQYJKoZIhvcNAQELBQAw
TzELMAkGA1UEBhMCVVMxKTAnBgNVBAoTIEludGVybmV0IFNlY3VyaXR5IFJlc2Vh
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oyi3B43njTOQ5yOf+1CceWxG1bQVs5ZufpsMljq4Ui0/1lvh+wjChP4kqKOJ2qxq
4RgqsahDYVvTH9w7jXbyLeiNdd8XM2w9U/t7y0Ff/9yi0GE44Za4rF2LN9d11TPA
mRGunUHBcnWEvgJBQl9nJEiU0Zsnvgc/ubhPgXRR4Xq37Z0j4r7g1SgEEzwxA57d
emyPxgcYxn/eR44/KJ4EBs+lVDR3veyJm+kXQ99b21/+jh5Xos1AnX5iItreGCc=
-----END CERTIFICATE-----
)EOF";

BearSSL::WiFiClientSecure  wifiClient;
BearSSL::X509List          trustedCA(caCert);
PubSubClient               mqtt(wifiClient);

void onMessage(char* topic, byte* payload, unsigned int len) {
  String msg = "";
  for (int i = 0; i < len; i++) msg += (char)payload[i];
  Serial.println("[" + String(topic) + "] " + msg);
}

void connectMQTT() {
  while (!mqtt.connected()) {
    Serial.print("Connecting (TLS)...");
    // Last Will: broker publishes "offline" to /out/ topic if device drops unexpectedly
    if (mqtt.connect(clientId.c_str(), mqttUser, mqttPass,
                     topicStatus.c_str(), 1, true, "offline")) {
      Serial.println(" connected!");
      mqtt.publish(topicStatus.c_str(), "online", true);   // birth message clears the retained "offline"
      mqtt.subscribe(topicRelay.c_str());
    } else {
      Serial.print(" failed, rc="); Serial.println(mqtt.state());
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  clientId = String(mqttUser) + "_" + String(ESP.getChipId(), HEX);
  configTime(3 * 3600, 0, "pool.ntp.org");   // TLS needs correct time

  WiFi.begin(ssid, wifiPass);
  while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); }
  Serial.println("\nWi-Fi: " + WiFi.localIP().toString());

  wifiClient.setTrustAnchors(&trustedCA);   // verify broker cert against ISRG Root X1
  mqtt.setServer(mqttHost, mqttPort);
  mqtt.setCallback(onMessage);
  mqtt.setBufferSize(512);
}

void loop() {
  if (!mqtt.connected()) connectMQTT();
  mqtt.loop();

  static unsigned long lastPub = 0;
  if (millis() - lastPub > 10000) {
    lastPub = millis();
    float temp = analogRead(A0) * 0.1;
    mqtt.publish(topicTemp.c_str(), String(temp, 2).c_str());
  }
}

// ESP32 — Secure MQTT connection (port 8883, TLS)
// WiFiClientSecure verifies the broker's Let's Encrypt certificate automatically.

#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <PubSubClient.h>

const char* ssid       = "YOUR_WIFI_SSID";
const char* wifiPass   = "YOUR_WIFI_PASSWORD";

const char* mqttHost   = "cloud.virtuino.com";
const int   mqttPort   = 8883;
const char* mqttUser   = "vr-abcd1234";
const char* mqttPass   = "YOUR_MQTT_PASSWORD";
String      clientId;                           // built in setup(): prefix + chip ID

// Built from mqttUser, so the account key is written only once
String deviceName  = "esp32";
String topicTemp   = String(mqttUser) + "/in/device/"  + deviceName + "/temperature";  // device publishes → cloud
String topicRelay  = String(mqttUser) + "/out/device/" + deviceName + "/relay1";       // device subscribes ← cloud
String topicStatus = String(mqttUser) + "/in/device/"  + deviceName + "/LWT";          // reserved LWT topic (online / offline)

// ── ISRG Root X1 — Let's Encrypt CA Certificate ───────────────────────────────
const char caCert[] = R"EOF(
-----BEGIN CERTIFICATE-----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jNPElpzVmbUq4JUagEiuTDkHzsxHpFKVK7q4+63SM1N95R1NbdWhscdCb+ZAJzVc
oyi3B43njTOQ5yOf+1CceWxG1bQVs5ZufpsMljq4Ui0/1lvh+wjChP4kqKOJ2qxq
4RgqsahDYVvTH9w7jXbyLeiNdd8XM2w9U/t7y0Ff/9yi0GE44Za4rF2LN9d11TPA
mRGunUHBcnWEvgJBQl9nJEiU0Zsnvgc/ubhPgXRR4Xq37Z0j4r7g1SgEEzwxA57d
emyPxgcYxn/eR44/KJ4EBs+lVDR3veyJm+kXQ99b21/+jh5Xos1AnX5iItreGCc=
-----END CERTIFICATE-----
)EOF";

WiFiClientSecure wifiClient;
PubSubClient     mqtt(wifiClient);

void onMessage(char* topic, byte* payload, unsigned int len) {
  String msg = "";
  for (unsigned int i = 0; i < len; i++) msg += (char)payload[i];
  Serial.println("[" + String(topic) + "] " + msg);

  if (String(topic) == topicRelay)
    digitalWrite(2, msg == "1" ? HIGH : LOW);
}

void connectMQTT() {
  while (!mqtt.connected()) {
    Serial.print("Connecting (TLS)...");
    // connect() with Last Will arguments: (id, user, pass, willTopic, willQoS, willRetain, willMsg)
    if (mqtt.connect(clientId.c_str(), mqttUser, mqttPass,
                     topicStatus.c_str(), 1, true, "offline")) {
      Serial.println(" connected!");
      mqtt.publish(topicStatus.c_str(), "online", true);     // birth message clears the retained "offline"
      mqtt.subscribe(topicRelay.c_str());
    } else {
      Serial.print(" failed, rc="); Serial.println(mqtt.state());
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  clientId = String(mqttUser) + "_" + String((uint32_t)ESP.getEfuseMac(), HEX);
  pinMode(2, OUTPUT);

  WiFi.begin(ssid, wifiPass);
  while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); }
  Serial.println("\nIP: " + WiFi.localIP().toString());

  wifiClient.setCACert(caCert);        // verify broker against ISRG Root X1

  mqtt.setServer(mqttHost, mqttPort);
  mqtt.setCallback(onMessage);
  mqtt.setKeepAlive(60);
  mqtt.setBufferSize(512);
}

void loop() {
  if (!mqtt.connected()) connectMQTT();
  mqtt.loop();

  static unsigned long last = 0;
  if (millis() - last > 10000) {
    last = millis();
    float temp = random(200, 300) / 10.0;
    mqtt.publish(topicTemp.c_str(), String(temp, 1).c_str());
  }
}