Command Confirmation

Knowing that a command actually reached and was applied by the device — not just that it was sent.

1What confirmation does

Say a user taps a light switch on a dashboard. Here's exactly what happens, step by step:

Two outcomes: either the device answers in time and everything — automations, both dashboards, and any third-party app — updates together; or it doesn't, and nothing changes anywhere. Never a half-applied, out-of-sync state.

2Steps to enable it

3Device code

Two command fields below, esp32/relay1 and esp32/relay2, both with confirmation on. Every field with confirmation needs its own echo — one you forget in the code will always time out.

// ── Topics = field names, exactly as in Console → Fields ─
// Each one is used for BOTH subscribe (receive the command)
// and publish (echo it back); the broker keeps the two
// directions apart automatically.
String topicRelay1 = "esp32/relay1";
String topicRelay2 = "esp32/relay2";

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

  if (String(topic) == topicRelay1) {
    digitalWrite(RELAY1_PIN, msg == "1" ? HIGH : LOW);
    mqtt.publish(topicRelay1.c_str(), msg.c_str());  // echo — confirms relay1
  }

  if (String(topic) == topicRelay2) {
    digitalWrite(RELAY2_PIN, msg == "1" ? HIGH : LOW);
    mqtt.publish(topicRelay2.c_str(), msg.c_str());  // echo — confirms relay2
  }
}

void setup() {
  // ... WiFi.begin(...), mqtt.setServer(...), mqtt.setCallback(onMessage) ...
  mqtt.subscribe(topicRelay1.c_str());
  mqtt.subscribe(topicRelay2.c_str());
}

4Complete sketch (the one from the video)

This is the whole program, ready to flash on an ESP32. It controls a green and a red LED from the dashboard, confirms every command, and publishes a virtual sensor value every 5 seconds.

Change only the four settings at the top — your Wi-Fi, and the MQTT credentials from Console → Keys & Sub Users → MQTT Credentials. The fields esp32/green_led, esp32/red_led and esp32/sensor must already exist in Console → Fields.

// ====================================================
// Virtuino Cloud - ESP32 example
//
// Shows two features:
//
//   1. COMMAND CONFIRMATION
//      The device echoes back every command it applies,
//      so the dashboard shows the REAL state of the
//      device, not just the state you asked for.
//
//   2. ONLINE / OFFLINE STATUS
//      Nothing to do here. Virtuino Cloud is told by
//      the broker when this device connects and when
//      it disconnects, so there is no extra code —
//      it appears in My Virtuino World under the
//      client ID below.
// ====================================================

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

// ----------------------------------------------------
// WiFi settings
// ----------------------------------------------------
const char* WIFI_SSID     = "YOUR_WIFI_SSID";
const char* WIFI_PASSWORD = "YOUR_WIFI_PASSWORD";

// ----------------------------------------------------
// Virtuino Cloud MQTT settings
// Console -> Keys & Sub Users -> MQTT Credentials
// ----------------------------------------------------
const char* MQTT_HOST = "cloud.virtuino.com";
const int   MQTT_PORT = 1883;

const char* MQTT_USER = "YOUR_SUB_ACCOUNT_KEY";
const char* MQTT_PASS = "YOUR_MQTT_PASSWORD";

// ----------------------------------------------------
// How often the device tells the broker it is alive.
//
// This also decides how fast Virtuino Cloud notices a
// power cut: about 1.5 x this value.
//   20 -> offline within ~30 seconds
//   60 -> offline within ~90 seconds (less traffic)
// ----------------------------------------------------
const uint16_t KEEP_ALIVE_SEC = 20;

// ----------------------------------------------------
// GPIO
// ----------------------------------------------------
#define GREEN_LED_PIN 13
#define RED_LED_PIN   12

// ----------------------------------------------------
// Virtuino Cloud fields — the topic IS the field name.
// Create them first in Console -> Fields, and turn
// "confirm commands" on for the two LED fields.
// ----------------------------------------------------
String topicGreen  = "esp32/green_led";   // command, confirmed
String topicRed    = "esp32/red_led";     // command, confirmed
String topicSensor = "esp32/sensor";      // sensor value, no confirmation

// ----------------------------------------------------

WiFiClient   wifiClient;
PubSubClient mqtt(wifiClient);

unsigned long lastSensorTime = 0;
const unsigned long SENSOR_INTERVAL = 5000;


// ====================================================
// WiFi connection
// ====================================================

void connectWiFi() {

  if (WiFi.status() == WL_CONNECTED) return;

  Serial.print("Connecting to WiFi");

  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);

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

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


// ====================================================
// MQTT callback
// ====================================================

void mqttCallback(char* topic, byte* payload, unsigned int length) {

  String message;

  for (unsigned int i = 0; i < length; i++) {
    message += (char)payload[i];
  }

  String receivedTopic = String(topic);

  Serial.print("MQTT received [");
  Serial.print(receivedTopic);
  Serial.print("] ");
  Serial.println(message);

  // --------------------------------------------------
  // GREEN LED
  // --------------------------------------------------

  if (receivedTopic == topicGreen) {

    if (message == "1") {
      digitalWrite(GREEN_LED_PIN, HIGH);
    }
    else if (message == "0") {
      digitalWrite(GREEN_LED_PIN, LOW);
    }
    else {
      return;          // Ignore invalid command
    }

    // -----------------------------------------------
    // VIRTUINO CLOUD COMMAND CONFIRMATION
    //
    // Publish the value back to the SAME topic, but
    // only AFTER the command has actually been applied.
    //
    // Virtuino Cloud treats this message as proof that
    // the device did the job, and marks the command as
    // confirmed. Until it arrives, the dashboard keeps
    // showing the command as pending.
    //
    // Send it here, at the end of the command, and NOT
    // when the message first arrives - otherwise you
    // would be confirming something you have not done.
    // -----------------------------------------------

    mqtt.publish(topicGreen.c_str(), message.c_str());

    Serial.println("Green LED command confirmed.");
  }


  // --------------------------------------------------
  // RED LED
  // --------------------------------------------------

  else if (receivedTopic == topicRed) {

    if (message == "1") {
      digitalWrite(RED_LED_PIN, HIGH);
    }
    else if (message == "0") {
      digitalWrite(RED_LED_PIN, LOW);
    }
    else {
      return;
    }

    // Virtuino Cloud confirmation - same as above

    mqtt.publish(topicRed.c_str(), message.c_str());

    Serial.println("Red LED command confirmed.");
  }
}


// ====================================================
// MQTT connection
// ====================================================

void connectMQTT() {

  while (!mqtt.connected()) {

    if (WiFi.status() != WL_CONNECTED) {
      connectWiFi();
    }

    Serial.print("Connecting to Virtuino Cloud MQTT...");

    // ------------------------------------------------
    // Client ID
    //
    // Any name you like. It is the name this board
    // shows in My Virtuino World, e.g. esp32-a1b2c3...
    //
    // The chip ID keeps it the same after every restart
    // and different on every board running this same
    // sketch. Boards sharing a client ID would keep
    // disconnecting each other.
    // ------------------------------------------------

    uint64_t chipId = ESP.getEfuseMac();

    String clientId =
      "esp32-" +
      String((uint32_t)(chipId >> 32), HEX) +
      String((uint32_t)chipId, HEX);


    // ------------------------------------------------
    // Connect
    //
    // Nothing else to pass. Virtuino Cloud is told by
    // the broker when this client connects and when it
    // disconnects, including after a power cut.
    // ------------------------------------------------

    if (mqtt.connect(clientId.c_str(), MQTT_USER, MQTT_PASS)) {

      Serial.print(" connected as ");
      Serial.println(clientId);

      // Subscribe to commands
      mqtt.subscribe(topicGreen.c_str());
      mqtt.subscribe(topicRed.c_str());

      Serial.println("Subscribed to LED commands.");
    }

    else {

      Serial.print(" failed, rc=");
      Serial.println(mqtt.state());

      delay(4000);
    }
  }
}


// ====================================================
// Setup
// ====================================================

void setup() {

  Serial.begin(115200);

  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);

  digitalWrite(GREEN_LED_PIN, LOW);
  digitalWrite(RED_LED_PIN, LOW);

  // Random generator, used by the virtual sensor below
  randomSeed(esp_random());

  connectWiFi();

  mqtt.setServer(MQTT_HOST, MQTT_PORT);
  mqtt.setCallback(mqttCallback);

  mqtt.setKeepAlive(KEEP_ALIVE_SEC);
  mqtt.setBufferSize(512);
}


// ====================================================
// Main loop
// ====================================================

void loop() {

  if (WiFi.status() != WL_CONNECTED) {
    connectWiFi();
  }

  if (!mqtt.connected()) {
    connectMQTT();
  }

  mqtt.loop();


  // --------------------------------------------------
  // Virtual sensor every 5 seconds
  // --------------------------------------------------

  if (millis() - lastSensorTime >= SENSOR_INTERVAL) {

    lastSensorTime = millis();

    // Example random value: 0.0 - 100.0
    float sensorValue = random(0, 1001) / 10.0;

    String value = String(sensorValue, 1);

    mqtt.publish(topicSensor.c_str(), value.c_str());

    Serial.print("Virtual sensor: ");
    Serial.println(value);
  }
}