Sensirion provides a low-cost CO₂ monitor reference design to enable IoT and HVAC companies to rapidly develop their own CO₂ monitor solution. Due to the pandemic, there is an increased demand to measure indoor CO₂ concentrations. Scientific studies indicate that COVID-19 is airborne resulting in an increasing demand to keep CO₂ concentrations in schools, offices and other crowded indoor environments monitored. Simple CO₂ monitors help to know when it's time to ventilate the room.

Here is an overview of the topics on this website:

• Use Case: CO₂ Monitor
• CO₂ Monitor App
• Advantages of Using the CO₂ Monitor Reference Design
• Contact Us: How to Go from Reference Design to a Product?
• Maker Tutorial: Create Your Own CO₂ Monitor

Why to Measure CO2 Indoors?

Too much CO₂ in the air results in a stuffy climate, decreasing occupant work performance and increasing risk of infection with viruses. Since indoor CO₂ is mostly emitted from humans, there is a correlation between indoor CO₂ concentration and exhaled air. Exhaled air contains human aerosols, which might carry viruses like COVID-19. Therefore, CO₂ concentration can be used as a trigger to ventilate for lower airborne virus infection risks. Especially in winter, or when outside air pollution levels are high, it is beneficial for occupants to ventilate only as needed. CO₂ monitors help to trigger ventilation and to create awareness for efficient ventilation routines, especially in schools without automated ventilation systems.

Efficient ventilation, an increase in productivity and the possibility of reducing virus infection: CO₂ monitors can be widely used in homes, schools, institutions, companies and many more. A CO₂ monitor, which works like a traffic light offers a simple but user-friendly solution.

The CO₂ monitor comes already calibrated and only needs to be connected to electricity. The LED display can be used immediately for CO₂ monitoring. Whenever possible, the CO₂ monitor should be placed at eye level and not directly next to windows or people.

The LED light then informs occpupants via three color levels about the CO₂ concentration level in their room. The top part of the CO₂ monitor is made of transparent plastic and provides a well visible light indication.

The standard thresholds are as follows:

• Green: <1000 ppm
• Yellow: 1000 - 1600 ppm
• Red: > 1600 ppm

Users who need more detailed information, can use the CO₂ monitoring app to read out the precise concentration via Bluetooth.

Features

• Enables efficient ventilation thanks to intuitive light indication – no complicated displays
• Advanced CO₂ history and data download via app
• Wall- or tabletop mounting, both possible
• USB powered - multiple power sources possible (e.g. powerbank, laptop, USB AC adapter etc.)
• Highest CO₂ measurement accuracy with Sensirion's established SCD30 CO₂ sensor: ±(30 ppm + 3% of measured value)

The CO₂ monitor reference design was created for companies, which like to develop their own commercial CO₂ monitor relying on their individual supply chains. It is not intended as an Arduino-based maker project, but as the foundation for developing a robust high-volume low-cost CO₂ monitor.

Sensirion provides the mechanical design and electrical design for companies with the intention to make a commercial CO₂ monitor on request.

Features of the CO₂ Monitoring App

• Displays precise real-time CO₂ concentration
• Three months of historic data (time chart: +8000 data points)
• Data export & download from app
• Manage multiple monitors in one app
• Set thresholds of LED color via app
• Set light intensity of LED via app

For our maker community we gladly provide a tutorial enabling the setup of a CO₂ monitor using our SCD30 CO₂ sensor for sending CO₂ measurements via Bluetooth to nearby phones. In this tutorial we guide you through all necessary steps to build your own monitor. Furthermore, we provide a compatible app for Android and iOS.

Learn more about the hardware, software and monitor setup and kick-start your own project now.

Check out the tutorial here.