This project involves an IoT application that uses ESP32 and the ThingsBoard platform to collect data from an SHT4x temperature and humidity sensor and send this data to a ThingsBoard server.

#include <ThingsBoard.h>
#include <Arduino_MQTT_Client.h>
#include <WiFiClient.h>
#include <ArduinoJson.h>
#include "Adafruit_SHT4x.h"

This section includes the libraries required for the project. ThingsBoard.h, Arduino_MQTT_Client.h, and WiFiClient.h are necessary for connecting your IoT device to the ThingsBoard server over the internet. ArduinoJson.h is used for data processing and MQTT messages. Adafruit_SHT4x.h is the library required to interact with the SHT4x sensor.

#define WIFI_AP_NAME        "Vodafonenet_Wifi_8047"
#define WIFI_PASSWORD       "U5DerrGGDUEz"
#define TOKEN               "pHYZ7VkKvoxTOyy6LDc1"
#define THINGSBOARD_SERVER  "demo.thingsboard.io"

constexpr uint16_t MAX_MESSAGE_SIZE = 128;
constexpr uint16_t THINGSBOARD_PORT = 1883;

This section defines settings like the name and password of the WiFi network, and the ThingsBoard server and connection port.

WiFiClient espClient;
Arduino_MQTT_Client mqttClient(espClient);
ThingsBoard tb(mqttClient, MAX_MESSAGE_SIZE);
int status = WL_IDLE_STATUS;

Adafruit_SHT4x sht4 = Adafruit_SHT4x();

Here, variables required for the WiFi and MQTT client, ThingsBoard object, and SHT4x sensor are defined.

Functions like InitWiFi, reconnect, shtBegin, and readTemperatureAndHumidity are used for initiating WiFi connection, reconnecting, initializing the SHT4x sensor, and reading temperature and humidity data from the sensor, respectively. The SHT40Data structure is defined to store temperature and humidity data.

setup and loop are the main functions. The setup function runs once when the program starts and does the necessary initial setups. The loop function runs continuously and reads sensor data and sends it to ThingsBoard.