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.
Complete Project Resources
Full project is available at Play with Circuit
How to Build a Weather Monitoring System Using ESP32-S3 Smart Display and LVGL