Introduction to Programming and Physical Computing Seminar
This project focuses on developing a smart air quality monitoring system using a Seeed Lotus microcontroller, an MQ-135 air quality sensor, a 0.96” OLED display, a buzzer, a small motor or fan, and a panel with three LEDs to indicate air quality levels. The system continuously measures CO₂ concentrations and other volatile compounds in indoor environments to provide real-time feedback on air quality.
The MQ-135 sensor captures analog readings of air pollutants, which the microcontroller processes to estimate CO₂ levels. Based on these measurements, the system classifies air quality into three categories: GOOD, MODERATE, or BAD. Each category is represented visually using three colored LEDs: green for good, yellow for moderate, and red for bad air quality and on the OLED display, which shows the current CO₂ concentration and the corresponding status.
When air quality drops to a BAD level (e.g., CO₂ exceeds 400 ppm), the system triggers a buzzer alert to notify occupants. Additionally, the motor or small fan can be activated automatically to improve ventilation and reduce CO₂ concentrations, providing a practical response to maintain healthier indoor air. The OLED display offers a clear, real-time visual representation of environmental conditions, making the system intuitive and easy to use.
Bill of Materials
1 Seeed Lotus board – Microcontroller – Main controller
1 MQ-135 Air Quality Sensor – Sensor – Analog output for CO₂ levels
1 0.96” OLED I²C – Display – 128×64 screen for visual output
3 LEDs (green, yellow, red) – Indicators – For GOOD, MODERATE, BAD air levels
3 220Ω resistors – Resistors – Current limiting for LEDs
1 Grove buzzer – Buzzer – Alerts BAD air levels
1 Motor / Fan – Servo SM-S2309S – Turns on when air levels are detected as BAD
7 Jumper wires – Wires – Connections between components
1 Breadboard – Bread Board – For LEDs and component connections
The project emphasizes real-time monitoring, alert mechanisms, and automated environmental control, demonstrating how embedded systems can enhance indoor health and safety. It serves as a prototype for applications in homes, classrooms, or offices, where maintaining good air quality is essential for comfort, concentration, and well-being.This compact system is scalable and adaptable, allowing for future expansions such as adding Wi-Fi connectivity for remote monitoring, cloud-based data logging, or integration with HVAC systems for automated ventilation control. By combining sensor data, visual and auditory alerts, and actuator-based responses, this project provides a practical demonstration of a smart, responsive indoor air quality management system.
