CO2 Monitor

Project completed: August 2021

In this project, I build a simple to use, handheld CO2 monitor capable of displaying the real CO2 value for a family member. The device simply reads the CO2 value from the sensor. This value is then displayed on the seven segment display. The device is powered from a USB battery bank so the device can be moved around.

I wanted to keep the cost as low as possible. As a result, I reused the perfboard and Arduino Nano, which I had left over from previous projects. The CO2 sensor is the most expensive part of the whole device. There are cheaper sensors which are capable of reporting CO2 values, but they only calculate the approximate CO2 value, not the actual reading. As a result, the decision was made to use the more expensive sensor.

When the device is powered up, it goes straight into reading the CO2 reading. Whatever the seven segment display shows is the CO2 reading. There is nothing to configure. This makes the device easy to use which was one if the criteria.

Below is an image of the device in action.

CO2 Measuring Device

Parts used

  • Sensirion SCD-41 CO2 sensor
  • Perfboard
  • Arduino Nano
  • 4 digit, 7 segment display
  • 7 220 ohm resistors

The code for this project can be found here