AQI Monitor
The Air Quality Monitor is a compact, Arduino-based device designed to measure and display real-time air quality data. It was specifically built to address rising pollution levels in Delhi NCR, providing an easy-to-use solution for society guards and residents to monitor air conditions.
The monitor continuously measures particulate matter (PM) and toxic gases, providing an accurate Air Quality Index (AQI) reading. The device displays the AQI on an OLED screen and uses very simple indicators to indicate whether the air is safe or unsafe.
Step-by-Step Working
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Air Sampling and Detection:
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The device uses two key sensors:
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GP2Y1010AU0F Dust Sensor:
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Measures particulate matter (PM) levels by emitting an LED beam into the surrounding air.
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When particles scatter the light, a photodetector captures the reflection and converts it into an analog voltage signal.
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The intensity of the scattered light corresponds to the PM concentration.
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MQ-135 Gas Sensor:
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Detects harmful gases like CO₂, NH₃, NOx, benzene, and alcohol vapors.
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The sensor’s internal heating element activates chemical reactions with the gases, altering the resistance and generating an analog signal proportional to the gas concentration.
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Signal Processing:
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The Arduino Uno reads the analog signals from both sensors.
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The analog signals are converted into digital AQI values using the Arduino’s ADC (Analog-to-Digital Converter).
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To improve accuracy and stability:
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The code implements averaging algorithms to smooth out fluctuations and prevent false spikes.
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The system continuously updates the AQI every 2–3 seconds.
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Data Display and Alert System:
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The device uses a 0.96-inch OLED screen to display the AQI.
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The screen shows the current air quality with color-coded indicators:
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Safe (AQI < 100).
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Moderate (100 ≤ AQI < 200).
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Unsafe (AQI ≥ 200, masks recommended).
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