In this project, I built a weather monitoring system using an ESP32-S3 Smart Display, a BME280 sensor, a rain sensor, and an LDR module. The system continuously measures environmental conditions and presents the information through a graphical interface created with LVGL.

Besides providing live weather information, this project serves as a great example of combining sensor interfacing with embedded GUI development.

System Overview

The weather station performs three major tasks:

Acquiring environmental measurements.
Processing sensor data.
Displaying information on a graphical dashboard.

The ESP32-S3 acts as the processing unit while LVGL provides the user interface.

How the System Works

The sensors continuously collect information from the environment. The ESP32-S3 processes the measurements and updates the dashboard in real time.

The complete workflow consists of:

Environmental data acquisition.
Sensor processing.
Graphical visualization.

Acquiring Environmental Data

Three sensors are used to monitor weather conditions.

BME280 Sensor

The BME280 provides:

Temperature
Relative humidity
Atmospheric pressure

Pressure measurements are also used to estimate altitude.

Communication with the controller takes place through the I2C interface.

Rain Sensor

Rain detection is performed using a conductive rain sensor.

Water droplets modify the conductivity of the sensor plate, producing changes in the output voltage. By monitoring these changes, the system determines whether rainfall is present.

Light Sensor

An LDR module is used to detect ambient light conditions.

Since the resistance of the photoresistor changes with illumination intensity, the controller can distinguish between daytime and nighttime conditions.

Sensor Processing

The ESP32-S3 performs several tasks:

Reading BME280 measurements.
Acquiring analog values from the rain sensor.
Measuring ambient light intensity.
Calculating altitude from pressure values.
Determining rain status.
Detecting day and night conditions.
Updating the graphical interface.

Continuous processing ensures that the dashboard always reflects current environmental conditions.

Visualizing Data with LVGL

Instead of showing plain numerical values, the project uses LVGL to create a more user-friendly interface.

The dashboard displays:

Temperature
Humidity
Pressure
Altitude
Rain status
Day/night indication

Icons and labels make the information easier to interpret and provide a more polished user experience.

Hardware Requirements

The project uses:

ESP32-S3 Smart Display
BME280 Sensor
Rain Sensor
LDR Module
Breadboard
Jumper Wires
USB Cable

Since the display module contains both the controller and the screen, the overall hardware remains compact.

Software Requirements

Development is performed using:

Visual Studio Code
ESP-IDF Extension
ESP-IDF v5.3.5
Python 3.11
Bosch BME280 Library
LVGL v8

These components provide support for sensor communication and graphical rendering.

Circuit Connections

The BME280 communicates with the ESP32-S3 over the I2C bus.

Connections:

VCC → 3.3 V
GND → GND
SDA → GPIO9
SCL → GPIO10

The rain sensor uses an analog output connected to GPIO7.

Connections:

VCC → 3.3 V
GND → GND
AO → GPIO7

The LDR module is connected to GPIO6.

Connections:

VCC → 3.3 V
GND → GND
AO → GPIO6

All sensors share the same 3.3 V supply and common ground.

Software Architecture

Although ESP-IDF contains many framework files, only a few modules are directly related to the application.

main.cpp

This file acts as the application entry point.

Responsibilities include:

Display initialization.
LVGL configuration.
Sensor initialization.
Dashboard creation.
Real-time screen updates.

sensors.c

This module serves as the sensor abstraction layer.

Functions include:

Reading BME280 measurements.
Pressure-based altitude estimation.
Rain sensor acquisition.
Light intensity measurements.
Environmental condition classification.

Separating sensor management from UI logic improves maintainability and simplifies future expansion.

Applications

The same architecture can be extended for:

Smart home systems
Greenhouse monitoring
IoT dashboards
Data logging
Industrial monitoring
Environmental sensing projects

Video

Final Thoughts

Combining an ESP32-S3 Smart Display with environmental sensors and LVGL makes it possible to build a compact and interactive weather station.

Beyond simply displaying sensor values, the project demonstrates how embedded hardware and graphical interfaces can work together to create practical IoT applications.