AeroGuard 180
A smart gas-detection and evacuation system with a 180 ° pivoting fan
Author: Victor Sandu
GitHub Project Link: https://github.com/UPB-PMRust-Students/proiect-Victor270104
Description
AeroGuard 180 continuously monitors the concentration of smoke and automatically evacuates contaminated air through a blower fan that can be rotated up to 180 °. The system sends Wi‑Fi alerts and provides local visual (LED) and audible (buzzer) feedback.
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Dual MQ‑2 gas sensors detect smoke, LPG, and CO in real‑time.
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An SG90 micro‑servo sweeps a 3 – 6 V DC blower fan up to 180 °, directing the airflow toward the gas source.
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Raspberry Pi Pico 2 W runs async Rust firmware, processes sensor data, and publishes MQTT/HTTP alerts.
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Status LEDs (green = safe, red = alert) and a passive buzzer offer immediate on‑site feedback.
Motivation
This project lets me dive deeper into embedded development with Rust while addressing a real‑world safety issue: preventing smoke or fires in homes and small labs by automating ventilation and issuing rapid notifications.
Architecture
MQ‑2 gas sensors – supply analog voltage proportional to smoke/gas concentration. The Pico’s ADC samples these signals continuously for threshold analysis.
SG90 micro‑servo – receives PWM commands from the Pico and rotates the blower fan up to 180 °, so contaminated air is pushed away from the danger zone.
L298N dual H‑bridge – drives the 3 – 6 V DC blower fan under Pico control (start/stop and optional speed modulation).
Status LEDs & passive buzzer – connected to GPIO pins; green LED indicates safe air, red LED and buzzer indicate dangerous concentrations and trigger ventilation.
LED indicators:
- Green LED: Air concentration is safe.
- Red LED: Air concentration is dangerous.
Power source – a single USB‑C cable from the laptop delivers 5 V. The Pico distributes logic power, while the L298N shares the same 5 V rail for the fan. No external batteries are required.
Log
Week 5 - 11 May
Week 12 - 18 May
Week 19 - 25 May
Hardware
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Raspberry Pi Pico 2 W:
- Purpose: Central control unit.
- Function: Runs Rust code to control sensors, fan, and LEDs.
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MQ‑2 Gas Sensor Module:
- Purpose: Detect flammable gases, CO, and smoke.
- Function: Provide analog voltage proportional to gas concentration—read by the Pico ADC to trigger ventilation and alarms.
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Micro‑servo SG90 180 °:
- Purpose: Mechanically orient the blower fan.
- Function: Receives PWM from the Pico to sweep up to 180 °, directing the airflow toward the contamination source.
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DC Blower Fan 3 V – 6 V:
- Purpose: Evacuate contaminated air from the monitored space.
- Function: Powered through an H‑bridge; speed and on/off state controlled by the Pico.
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L298N Dual H‑Bridge Driver:
- Purpose: Safely switch and drive the DC blower motor (with one spare channel for future actuators).
- Function: Translates Pico logic‑level signals into motor currents up to 2 A.
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LEDs (Red, Green):
- Purpose: Visual indicator.
- Function: Green = safe, Red = alert; driven by Pico GPIO lines via current‑limiting resistors.
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Passive Buzzer 3 V – 3.3 V:
- Purpose: Audible warning when gas thresholds are exceeded.
- Function: Generates a tone when toggled by a Pico GPIO pin.
Hardware Overview
- The Pico 2 W reads air concentration.
- Based on air conditions, it controls the ventilator and the motors.
- LEDs give real-time feedback on air concentration.
Schematics
Bill of Materials
| Device | Usage | Price |
|---|---|---|
| Raspberry Pi Pico 2W | Main microcontroller | ~40 RON |
| Senzor Module Gas MQ-2 | Air concentration sensing | ~11 RON |
| Micro Servomotor SG90 180° | Pivot for fan | ~12 RON |
| Driver module Dual L298N | Driver for motor | ~11 RON |
| Motor DC 3V-6V | Motor | ~11 RON |
| 3V Passive Buzzer | Buzzer | ~1 RON |
Software
| Library | Description | Usage |
|---|---|---|
| embassy-rp | RP2040 async embedded support | Core hardware abstraction |
| embedded-hal | Hardware abstraction layer | GPIO, ADC, PWM |