Overview
Developed at American Study Education JSC between March and May 2026, Breezi is an advanced smart air purification and indoor climate workstation. The device monitors atmospheric particulate concentrations, volatile organic compounds, ozone, temperature, and humidity, dynamically modulating air filtration throughput according to real-time international Air Quality Index (AQI) thresholds.
Hardware & Sensor Integration
The system centers around an ESP32 dual-core SoC orchestrating a suite of laboratory-grade environmental sensors:
- Plantower PMS5003: Laser scattering optical particle sensor measuring fine particulate matter (PM1.0, PM2.5, PM10) in µg/m³.
- Sensirion SHT31-D: High-precision capacitive humidity (±2%) and band-gap temperature (±0.2°C) sensor over I2C.
- MQ-135 Gas Sensor: SnO2 semiconductor sensor calibrated for hazardous indoor air contaminants (NH3, NOx, alcohol, benzene, smoke, CO2).
- MQ-131 Gas Sensor: Specialized metal-oxide semiconductor sensor detecting trace ozone (O₃) levels.
- PWM Fan Driver Circuit: High-frequency MOSFET driver controlling a 12V brushless centrifugal blower fan with whisper-quiet progressive speed ramping.
Graphical Interface & Firmware
- LVGL (Light and Versatile Graphics Library): Deployed on a 2.8-inch ILI9341 SPI color TFT display (320x240). The interface features custom circular gauge dials, dynamic AQI color indicators (Green: Good, Yellow: Moderate, Orange: Unhealthy, Red: Hazardous), real-time sparkline graphs, and settings controls.
- FreeRTOS Multitasking Architecture:
- Task 1 (Priority High): UART sensor acquisition, digital filtering, and moving average calculation.
- Task 2 (Priority Medium): LVGL rendering loop at 30 FPS with DMA SPI transfer.
- Task 3 (Priority Low): WiFi station, NTP synchronization, and local HTTP dashboard server.
- OpenWeatherMap API Integration: Complements local indoor telemetry with regional outdoor ambient weather forecasts over WiFi.
Key Outcomes
Breezi demonstrated significant noise reduction and energy savings compared to conventional constant-speed purifiers by dynamically throttling filtration speeds based on actual air pollution severity. The project is open-sourced on GitHub - Breezi-Air-Purifier.