Smart Classroom Air Quality FYP: SCD41, BME280 and MQ135 Practical Guide
Plan a realistic classroom air quality FYP with ESP32, proper CO2 sensing, temperature, humidity, alerts, and honest sensor limitations.
Rectronx
2026-07-14
Quick Summary
A smart classroom air quality project can be strong when it separates real CO2 measurement from general gas sensing. Use SCD41 or a similar NDIR/photoacoustic CO2 sensor for CO2 trends, BME280 for temperature and humidity, and MQ135 only for relative gas or smoke trend experiments.
Project Scope
The system should monitor classroom conditions, display readings, trigger ventilation suggestions, and store data for reports. A good demo shows how readings change when occupancy or airflow changes.
Keep the claim practical: the prototype supports awareness and ventilation decisions. It does not certify indoor air quality for health compliance.
Suggested Components
Use ESP32, SCD41 or SCD30 for CO2, BME280 for temperature and humidity, OLED display, buzzer or LED indicator, and a dashboard. MQ135 can be included as a comparison sensor, but not as a precise CO2 sensor.
Build Steps
- Read each sensor separately using known libraries.
- Log readings with timestamps.
- Build threshold levels for normal, warning, and poor ventilation.
- Add a dashboard with historical charts.
- Compare readings near a window, closed room, and ventilated area.
Accuracy and Safety Notes
CO2 readings should come from a sensor designed for CO2. MQ135 output is affected by many gases, warm-up time, airflow, humidity, and calibration. Write this limitation clearly because it shows engineering maturity.
Common Mistakes
- Calling MQ135 a reliable CO2 sensor.
- Skipping warm-up and calibration notes.
- Placing sensors near fans or direct sunlight.
- No timestamped data for evaluation.
- Using only one short test period.