Networking and Communications

My networking proyect

For this week, my goal is to connect to my microcontroller board. The purpose of this project is to learn how to test the wireless conneciton of my XIAO ESP32-C6 via Wi-Fi. This type of communications are crutial for making big proyects because you need to connect properly to send and recieve important data.

My Setup

Hardware

This week is so simple in terms of hardware, because all I needed was my XIAO ESP32-C6 and check the connections with the built-in LED, so thats all.

XIAO ESP32-C6 PINOUT.

My networking setup.

Programming with ESP-IDF and C

The logic is simple, I first connect my XIAO to Wi-Fi, and then access to a private fabacademy server via MQTT (mosquitto) broker, in which I can make my board to publish for sending data or subscribe for receiving data. For this proyect I will subscribe the XIAO to a topic called CMD, and then in my PC or phone terminal I will write 1 or 0 and then the XIAO receive this data and turns on and off a LED based on the command.

Logic and Libraries

Because I'm using ESP-IDF and C, this program needs some librares like wifi_sta.h or mqtt_client_app.h for connecting properly to the mqtt broker, and I divided all that is needed on separate files that the main program calls for using (you can do everything in the same program but it looks prettier).

Main Code

    // main.c (ESP32-C6 / ESP-IDF)

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_err.h"
#include "esp_log.h"
#include "nvs_flash.h"

#include "wifi_sta.h"
#include "mqtt_client_app.h"

static const char *TAG = "APP_MAIN";

#ifndef WIFI_SSID
#define WIFI_SSID "HERE GOES YOUR WIFI 2.4G NAME"
#endif

#ifndef WIFI_PASS
#define WIFI_PASS "YOUR PASSWORD"
#endif


#ifndef CONFIG_MQTT_BROKER_URI
#define CONFIG_MQTT_BROKER_URI "mqtt://mqtt.fabcloud.org:1883" // fab server
#endif


#define MQTT_USER "user"
#define MQTT_PASS "pass (you need permision to use the private fab server, otherwise you use mqtt.test.org:1833)"

void app_main(void)
{
    ESP_LOGI(TAG, "Initialating system for ESP32-C6...");

   
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ESP_ERROR_CHECK(nvs_flash_init());
    } else {
        ESP_ERROR_CHECK(ret);
    }

 
    const char *ssid =
    #ifdef CONFIG_WIFI_SSID
        CONFIG_WIFI_SSID;
    #else
        WIFI_SSID;
    #endif

    const char *pass =
    #ifdef CONFIG_WIFI_PASSWORD
        CONFIG_WIFI_PASSWORD;
    #else
        WIFI_PASS;
    #endif


    ESP_LOGI(TAG, "Connecting to Wi-Fi: %s", ssid);

    esp_err_t wifi_err = wifi_sta_connect(ssid, pass, 30000); // 30s timeout
    if (wifi_err != ESP_OK) {
        ESP_LOGE(TAG, "Error connecting Wi-Fi: %s (0x%x)", esp_err_to_name(wifi_err), wifi_err);
        
        
        while (1) {
            vTaskDelay(pdMS_TO_TICKS(1000));
        }
    }

    ESP_LOGI(TAG, "Wi-Fi connected sucsessfully");


    ESP_LOGI(TAG, "Initialazing MQTT client: %s", CONFIG_MQTT_BROKER_URI);
    
  
    ESP_ERROR_CHECK(mqtt_app_start(CONFIG_MQTT_BROKER_URI, MQTT_USER, MQTT_PASS));

    while (1) {
        ESP_LOGI(TAG, "System working properly...");
        vTaskDelay(pdMS_TO_TICKS(10000)); // hearbeat
    }
}

Final Result

Here is a video demonstrating the operation of the XIAO, connecting to Wi-Fi and turning a LED on and of with the MQTT broker.

Final demonstration of the connection between XIAO and PC or Phone.

Files

Here you can download the original files generated for this week's project:

• 📁 Download all mqtt files (C/ESP-IDF)