The DIY CO2 meter and grapher for home and office use.

Features:

• display current CO2 level, temperature and humidity
• display historical graph of CO2 level for last 30 minutes
• switch to large display of CO2 level
• alarm when CO2 exceeds limit of 1000 ppm
• self calibration with countdown display

Electronics inside:

• Arduino nano
• 0.96" OLED display
• MQ135 sensor
• DHT11 sensor
• 6x6x4.3mm button

Arduino firmware and schematics at my github

Assembly instructions at my website in Russian or translated to English.

Anet ET4 Pro

No

Yes

0.3

30

Screen area requires supports. Button is better when printed with 0.1mm layer height.

Bottom part edges needs some sanding to get easy assembly/disassembly