Indoor air-quality monitoring

The problem

We spend most of the day in closed rooms where carbon dioxide rises gradually and unnoticed with every breath. The result is headaches, sluggishness, and poor focus that we blame on tiredness rather than the air. It gets worse in winter when all windows are shut. The problem is that stale air has no smell or color, so it's noticed late — while measurement detects it about an hour before you feel it.

How it works

1. MeasurementThe sensors read carbon dioxide, gases, dust, temperature, and humidity.
2. ComparisonReadings are compared with the known health limits for each indicator.
3. ClassificationThe system gives a clear air status: good, acceptable, or needs ventilation.
4. AlertsExceeding a limit triggers a visual and audible alert in the room.
5. FollowingThe dashboard shows the day's curve, revealing exactly when the air quality drops.
6. ResponseThe control output can run an exhaust fan or remind you to open the window.

Project features

• An instantly clear result in green and red, with no numbers that need explaining.
• The daily curve reveals a pattern nobody noticed before.
• It suits classrooms, offices, and bedrooms — a wide market.
• It can be linked to an exhaust fan, turning it into a control system, not just a display.
• All its parts are simple, and it's quick to build.

Expected challenges

These are the main obstacles to expect during the build, laid out clearly so you know them before you start.

• Low-cost carbon dioxide sensors are estimates and don't provide a true measurement.
• Gas sensors need a warm-up period before giving correct readings.
• The unit's position changes the reading: near the window differs from the middle of the room.
• Calibration drifts over time and with high humidity.
• Too many alerts make users ignore them, so the thresholds must be realistic.

The consultation gives you a solution for each one.

Expected committee questions

Prepare your answers in advance: these questions come up often in defenses of similar projects.

1. At what level is carbon dioxide considered high, and where does that limit come from?
2. How was the air-quality sensor calibrated?
3. What's the difference between a PM2.5 dust sensor and a general air-quality sensor?
4. How does the system control ventilation automatically?

Practice the defense, question by question