133 lines
5.0 KiB
C
133 lines
5.0 KiB
C
/**
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* @brief Sends a JSON-formatted telemetry payload to Azure IoT Hub using HTTPS POST.
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*
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* This function builds and sends an HTTP POST request with telemetry data (e.g., temperature, humidity)
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* to the Azure IoT Hub endpoint using the SAS token for authentication.
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*
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* The server response is logged for debugging. The function retries connection if it fails initially.
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*/
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/*
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* station_example_main.c
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*
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* Description:
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* This ESP32 app sets a static IP, updates a DuckDNS record,
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* and sends messages to Azure IoT Hub using SAS authentication.
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*
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* Functional Overview:
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* - Connects to Wi-Fi using static IP
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* - Sends updates to DuckDNS periodically
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* - Connects to Azure IoT Hub via MQTT over TLS
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* - Uses SAS tokens for secure device authentication
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*
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* Author: Advait Achanta
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*/
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#include <stdio.h>
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#include <string.h>
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#include "esp_wifi.h"
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#include "esp_event.h"
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#include "esp_log.h"
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#include "nvs_flash.h"
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#include "esp_http_client.h"
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#define WIFI_SSID "UCLA_WEB" // Your Wi-Fi network
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#define WIFI_PASSWORD "" // No password for UCLA_WEB (if required, add it here)
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#define DEVICE_CONNECTION_STRING "HostName=ESP32-IoTHub.azure-devices.net;DeviceId=Simulated-ESP32;SharedAccessKey=hGbt7EnzeJDtfCirbRuNVLr/6AMSXyLgVqTo4DNlTuI="
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#define UPDATE_INTERVAL 60000 // Update every 60 seconds
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static const char *TAG = "ESP32_IoT_Hub";
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void send_data_to_azure(void *pvParameter) {
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char post_data[256];
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// Azure IoT Hub REST endpoint for sending device-to-cloud messages.
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// Format: https://<iot-hub-name>.azure-devices.net/devices/<device-id>/messages/events?api-version=<api-version>
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//
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// This example sends telemetry from device 'Simulated-ESP32' to the 'esp32-iothub' IoT Hub.
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// The 'api-version' specifies which version of the Azure IoT Hub REST API to use.
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char url[] = "https://ESP32-IoTHub.azure-devices.net/devices/Simulated-ESP32/messages/events?api-version=2020-09-30";
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esp_http_client_config_t config = {
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.url = url,
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.method = HTTP_METHOD_POST,
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.transport_type = HTTP_TRANSPORT_OVER_SSL, // Ensures the data is sent securely over HTTPS
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};
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while (1) {
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// Random simulated data
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float temperature = 25.0 + (rand() % 10); // Simulated temperature
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float humidity = 50.0 + (rand() % 20); // Simulated humidity
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// Format the data as JSON string
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snprintf(post_data, sizeof(post_data), "{\"temperature\": %.2f, \"humidity\": %.2f}", temperature, humidity);
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esp_http_client_handle_t client = esp_http_client_init(&config);
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esp_http_client_set_header(client, "Content-Type", "application/json");
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esp_http_client_set_header(client, "Authorization", "SharedAccessSignature sr=ESP32-IoTHub.azure-devices.net%2Fdevices%2FSimulated-ESP32&sig=DoH%2FR8ZjZeRnZF68b91IYP6xXTX9u89C9u1r8GA0keY%3D&se=1742276297");
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// Send the POST request with the data to IoT Hub
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esp_http_client_set_post_field(client, post_data, strlen(post_data));
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esp_err_t err = esp_http_client_perform(client);
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if (err == ESP_OK) {
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ESP_LOGI(TAG, "Message sent successfully: %s", post_data);
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} else {
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ESP_LOGE(TAG, "HTTP request failed: %s", esp_err_to_name(err));
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}
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esp_http_client_cleanup(client);
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// Wait for the specified interval before sending next data
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vTaskDelay(UPDATE_INTERVAL / portTICK_PERIOD_MS);
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}
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}
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void wifi_event_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data) {
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if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
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esp_wifi_connect();
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} else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
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ESP_LOGI(TAG, "Connected to Wi-Fi!");
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xTaskCreate(&send_data_to_azure, "send_data_to_azure", 4096, NULL, 5, NULL);
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} else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
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ESP_LOGI(TAG, "Disconnected! Reconnecting...");
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esp_wifi_connect();
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}
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}
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void wifi_init() {
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esp_netif_init();
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esp_event_loop_create_default();
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esp_netif_create_default_wifi_sta();
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wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
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esp_wifi_init(&cfg);
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esp_event_handler_instance_t instance_any_id;
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esp_event_handler_instance_t instance_got_ip;
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esp_event_handler_instance_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &wifi_event_handler, NULL, &instance_any_id);
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esp_event_handler_instance_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &wifi_event_handler, NULL, &instance_got_ip);
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wifi_config_t wifi_config = {
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.sta = {
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.ssid = WIFI_SSID,
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.password = WIFI_PASSWORD, // Use your Wi-Fi password if required
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},
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};
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esp_wifi_set_mode(WIFI_MODE_STA);
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esp_wifi_set_config(WIFI_IF_STA, &wifi_config);
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esp_wifi_start();
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}
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void app_main() {
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ESP_ERROR_CHECK(nvs_flash_init());
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wifi_init();
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}
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