MQTT is an OASIS standard messaging protocol for the Internet of Things (IoT) and one of the protocols supported by akenza.
It is designed as an extremely lightweight publish/subscribe messaging protocol that is ideal for connecting remote devices with a small code footprint and minimal network bandwidth. MQTT is used in various industries.
To run this project, we used akenza as an IoT platform, as it runs an open-source MQTT broker from Eclipse Mosquitto. By using a combination of MQTT and API functionalities, we have been able to automatically create Digital Twins for our device.
As Hardware, we have chosen an Arduino Uno WiFi Rev2.
1. Configure the Arduino Device
1.1 Set up the WiFi Connection
To have the Arduino Uno Wifi able to connect to WiFi, we used the WiFiNINA library, available in the Library Manager of Arduino IDE.
1.1.1 Manage Username and Password
To manage Username and Password, we have created an additional header file called arudino_secrets.h
#define SECRET_SSID "<your username>"
#define SECRET_PASS "<your password>"
1.1.2 WiFi Connection Code
The code to connect Arduino to WiFi is reported as below:
#include <WiFiNINA.h>
#include "arduino_secrets.h"
///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID; // your network SSID (name)
char pass[] = SECRET_PASS; // your network password (use for WPA, or use as key for WEP)
WiFiClient wifiClient;
void setup() {
//Initialize serial and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// attempt to connect to Wifi network:
Serial.print("Attempting to connect to WPA SSID: ");
Serial.println(ssid);
while (WiFi.begin(ssid, pass) != WL_CONNECTED) {
// failed, retry
Serial.print(".");
delay(5000);
}
Serial.println("You're connected to the network");
Serial.println();
}
void loop()
{}
1.2 Set up the MQTT Connection to akenza
For security reasons, akenza only supports authenticated connections via MQTT. For this, we have chosen as library PubSubClient to manage our MQTT connection. This enables us to use username and passwords in our connection string.
#include <PubSubClient.h>
//MQTTClient mqttClient(WiFiClient);
char host[] = "mqtt.akenza.io";
char clientid[] = "Arduino";
char username[] = "<copy from Akenza Device Api configuration>";
char password[] = "<copy from Akenza Device Api configuration>";
char outTopic[] = "<copy from Akenza Device Api configuration>";
PubSubClient client(host, 1883, callback, wifiClient);
void setup() {
if (client.connect(host, username, password)) {
Serial.print("Connected to ");
Serial.println(host);
Serial.println();
boolean r = client.subscribe(outTopic);
Serial.print("Subscribed to ");
Serial.println(outTopic);
Serial.println();
}
else {
// connection failed
// mqttClient.state() will provide more information
// on why it failed.
Serial.print("Connection failed: ");
Serial.println(client.state());
Serial.println();
}
}