The world's most programmer-friendly CO2 Monitor

Why is this the world's most? Because Octocat is the most beloved mascot of programmers in the world. I think. ฅ^•ω•^ฅ

Features

• Display CO2 value in 5x5 LED matrix Round(CO2ppm / 100)
  • 4-7 Green color
  • 8-9 Yellow color
  • 10-19 Red color
  • over 20 (means 2000ppm~) Red filled rectangle is displayed
• Web server http://octocat.local
  • CO2 & temperature log graph for 24 Hours (GET /)
  • CO2 Sensor manual calibration (GET /calibrate)
  • mDNS support
• WiFi turn ON/OFF
  • push the LED Matrix button

Circuit diagram

• Octocat Figurine 3 inch (GitHub Shop)
• M5Stack Atom Matrix
• CO2 Sensor MH-Z19C
• 5V output DCDC boost converter
• Diode 1S2076A
• Electrolytic capacitor 47uF
• Ceramic capacitor 0.1uF
• DC jack (if needed)

How to build and upload to the device

Pre-requirement

• PlatformIO

% git clone https://github.com/komasayuki/co2-monitor.git
% cd co2-monitor

# make your own settings file
% cp ./src/config_CHANGE_ME_.h ./src/config.h

# change WiFi settings
% vi ./src/config.h

# build
% platformio run

# upload to M5Stack Atom Matrix
% platformio run -t upload

How to calibrate

Please take this device outside and open /calibrate in the browser when the CO2 value settles down. http://octocat.local/calibrate

If you want to change HTML for /

% cd tool
% npm install

% vi monitor.html

# minify and convert tool/monitor.html to src/indexhtml.h for arduino 
% npm start