GitHub - ericwooshem/DIY-Frugal-Arduino-CO2-Sensor: DIY Frugal CO₂ Sensor: Arduino & inexpensive parts to build a sub-$100 system to track and evaluate COVID-19 risk using CO₂ levels to estimate ventilation and occupancy.
![Adafruit SCD-40 - True CO2, Temperature and Humidity Sensor [STEMMA QT / Qwiic] : ID 5187 : $44.95 : Adafruit Industries, Unique & fun DIY electronics and kits Adafruit SCD-40 - True CO2, Temperature and Humidity Sensor [STEMMA QT / Qwiic] : ID 5187 : $44.95 : Adafruit Industries, Unique & fun DIY electronics and kits](https://cdn-shop.adafruit.com/970x728/5187-08.jpg)
Adafruit SCD-40 - True CO2, Temperature and Humidity Sensor [STEMMA QT / Qwiic] : ID 5187 : $44.95 : Adafruit Industries, Unique & fun DIY electronics and kits
![100,000ppm MH-Z16 NDIR CO2 Sensor with I2C/UART 5V/3.3V Interface for Arduino/Raspeberry Pi | Sandbox Electronics 100,000ppm MH-Z16 NDIR CO2 Sensor with I2C/UART 5V/3.3V Interface for Arduino/Raspeberry Pi | Sandbox Electronics](https://sandboxelectronics.com/wp-content/uploads/2015/09/SEN-000030_non-scale_3.jpg)