MQ Gas Alerting System

This repository contains an explanation to implement a simple gas checking system that toggles a Piezo-Buzzer when MQ-Sensor specific high concentration is detected

The script also sends a notifcation to Discord, if WEBHOOK_URL has a valid url

Getting Started

Needed: Transistor (to enable buzzer when GPIO Pin is triggered), Resistor for better accuracy (used 10kΩ), MQ-Sensor (used MQ-135) and Piezo-Buzzer (or similar)
Software: Python3 & pip
Hardware: Raspberry Pi 3b+

Execution of air quality script

python3 check-air.py is the main script
(Optional) Add a Discord webhook url to WEBHOOK_URL and toggle HAS_BUZZER variable
Remove file ending of main script -> It is executable without python3 command due to #!/usr/bin/env/python3
Script must then be moved to /usr/local/bin to be executable by simply writing the filename
- sudo mv FILENAME /usr/local/bin/
- sudo chmod +x /usr/local/bin/FILENAME - Add execution permission
To start the script on boot of Raspberry Pi:
- Create **FILENAME**.sh script from repo
- Move it to /etc/init.d and make it executable
  - sudo mv FILENAME.sh /etc/init.d/
  - sudo chmod +x /etc/init.d/FILENAME.sh
- Register script to be executed on boot:
  - sudo update-rc.d FILENAME.sh defaults
- Reboot Raspberry Pi or manually start the script:
  - sudo /etc/init.d/FILENAME.sh start

⚠️ Files that are moved to /usr/local/bin must be encoded in LF, not CRLF, otherwise they are not executable. Fix (VSCode): At the bottom right, change CRLF to LF Fix (Terminal): sudo sed -i -e 's/\r$//' /PATH/FILENAME