How Open Source & Open Hardware contribute to safer offices during the COVID19 pandemic

It is now firmly established that COVID19 is a airborne disease. There are numerous scientific papers showing how it spreads through the air: in restaurants¹ and buses, offices and even home buildings².

At Camptocamp, we mostly work from home since the beginning of the pandemic but we sometimes gather in small numbers for meetings (and also to welcome newcomers !).
To make these events as safe as possible, a small group of camptocampers designed and built CO2 sensing devices for our five offices (Paris, Chambéry, Lausanne, Olten, Munich).

We use CO2 as a proxy measure to how much of the air we breathe has already gone through someone else’s potentially infected lungs. The higher the CO2 level rises, the higher the risk to get infected.

The idea is not new: german schools use CO2 sensors since last fall to make sure ventilation is adequate to prevent super spreading among students.

CO2 level in fresh air is nowadays close to 415 ppm (keeps rising, unfortunately).

At rest, one emits 5 ml/s of CO2. If there are 5 people in a closed room for one hour, one can easily measure CO2 levels as high as 2500 ppm.

Regarding the COVID19 pandemic, it is commonly accepted that anything higher than 800 ppm in a public space puts you at risk. It has indeed been shown that, at this level, 1% of the air you breathe comes from someone else³.

The devices we built use Open Hardware widely known as Arduino-compatible microcontroller boards. The CO2 sensor is a swiss-made SCD30 device by Sensirion, which communicates with the board using the I2C bus.

The sketch we came up with relies on Open Source libraries such as https://github.com/sparkfun/SparkFun_SCD30_Arduino_Library, https://github.com/arkhipenko/TaskScheduler and the whole Arduino stack.

At the end of the day, we got several instances of this tiny little device showing the real time level of CO2 in the room.

When the CO2 level rises above 800 ppm, the screen color turns red, which indicates the room needs fresh air.

When the COVID19 pandemic is over (the sooner the better), these devices will stay relevant, since CO2 levels higher than 1000 ppm are proven to affect decision making and problem solving⁴ which are … key to our business !