How to connect to HiveMQ Cloud from Arduino

HiveMQ Cloud
1

I’m trying to make connection to HiveMQ cloud from Arduino, but get a connection failed with state “-2”. In the cluster details only ports 8883 (TLS) and 8884 (Websocket + TLS) are specified, but all the Arduino examples seem to use port 1883, e.g. Arduino PubSubClient - MQTT Client Library Encyclopedia.

The network I use is a WiFi defined as

#include <WiFiNINA.h>

// WiFi settings
char ssid[] = "***";          
char ssid_password[] = "***";  
int wifi_status = WL_IDLE_STATUS;

WiFiClient network;

void setup() {
  while (wifi_status != WL_CONNECTED) {
    Serial.print(".");
    wifi_status = WiFi.begin(ssid, ssid_password);
    delay(2500);
  }
}

I use this wifi network to connect to HiveMQ Cloud with:

#include <PubSubClient.h>

PubSubClient mqttClient(network);

const char* server = "xxx.s1.eu.hivemq.cloud";

void init_mqtt() {
  mqttClient.setServer(server, 1883);

  if (mqttClient.connect("Arduino", "xxx", "xxx")) {
    Serial.println("Connected");
  } else {
    Serial.print("Connection failed: ");
    Serial.println(mqttClient.state());
  }
}

Serial.println(mqttClient.state()); shows the error code -2.

How can I further investigate what is going wrong? Or do I need to do additional steps to be able to connect to TLS?

2

Hello Frank,

You are trying to connect to HiveMQ Cloud with the default MQTT port (1883). HiveMQ Cloud only allows the ports 8883 (TLS) and 8884 (Websocket + TLS). This is why your connection fails.

Or do I need to do additional steps to be able to connect to TLS?

Yes, you do need to take further steps. Good news is that a full fledge guide on how to do this will be available very soon.
In the meantime maybe you can find some help in this thread: MQTT with SSL/TLS · Issue #462 · knolleary/pubsubclient · GitHub

  • Yannick
3 Likes
3

Thanks for the feedback! How soon is very soon? :wink:

I guess the most important part is the certificate to be added into

// Set x509 CA root (must match server cert)
const char *x509CA PROGMEM = R"EOF("
-----BEGIN CERTIFICATE-----
[...]
-----END CERTIFICATE-----
")EOF";
4

Hi Frank,

In case it help, I’m able to connect on the hiveMQ Cloud server with an arduino MKR Wifi 1010 via the library ArduinoMqttClient ( GitHub - arduino-libraries/ArduinoMqttClient: ArduinoMqttClient Library for Arduino available on the Library Manager.

1 Like
5

Hello Frank :wink:

How soon is very soon?

HiveMQ Cloud now has a guide on how to connect with Arduino ESP8266. You can find it under Cluster Details > Getting Started > Arduino ESP8266. I hope this helps you :slight_smile:

- Yannick

2 Likes
6

For others looking for the correct link, you need a HiveMQ Cloud account and then can find the info on https://console.hivemq.cloud/clients/arduino-esp8266?uuid={YOUR_CLOUD_ID}

3 Likes