Metriful is launching a $39 “Sense” indoor air quality sensor module that works with the Raspberry Pi and other I2C-enabled systems. Other sensors include temperature, humidity, air pressure, light, and sound.

In recent months, much of the world’s population has spent a lot of time indoors, often crowded into small apartments. If the air quality has improved outside due to the pandemic, the same cannot always be said for the indoor realm.

Metriful has gone to Kickstarter launch a remarkably low-cost sensor board called Sense to help you find how much pollution has come inside and how much is being generated from within from HVAC, cooking, and manufactured goods. It also checks temperature, humidity, air pressure, light, sound, and even gives you a rough estimation of CO2. Metriful has posted example code and setup instructions for Raspberry Pi and Arduino on GitHub and offers additional documentation.

Sense and mobile UI
(click images to enlarge)

The Sense board sells for 31 Pounds ($39) or 34 Pounds ($42.80) for a model that adds a 10-pin header for those who want to avoid soldering. Oxfordshire, UK based startup Metriful has easily surpassed its modest KS goal and expects to ship in September.

Sense is not a Raspberry Pi HAT, but it can be hooked up to the Pi, Arduinos, and other boards with I2C interfaces. It may not be quite as easy to set up as indoor sensing HAT like Pimoroni’s $57 Enviro+ pHAT, which offers a similar line-up of sensors. On the other hand, Sense is much cheaper and since it supports both 3.3V and 5V logic levels, it can work with a wider variety of systems.

Sense detail view
(click image to enlarge)

Powered by an STM32 microcontroller, the 37.5 x 23.4 x 3.1mm module is equipped with sensors from Bosch, Sensortec, Vishay, and other manufacturers. Unlike Pimoroni, Metriful does not list most of the sensor models.

The centerpiece is a Bosch BME680 metal-oxide gas air quality sensor that checks for potentially toxic volatile organic compounds (VOCs). An algorithm generates an air quality index rating based on total measured VOCs and humidity conditions from the separate humidity sensor. Another algorithm can generate a rough estimate of VOCs from breath and can also estimate CO2 concentration.

Sense sensor specs (left) and different pin-styles available for optional pin header version
(click images to enlarge)

Sense has a pin header that supports a Shinyei PPD42 air particulate matter sensor that measures smoke, pollen, and dust. Customers will need to buy this low-cost sensor on their own.

Other sensors include a temperature sensor and an air pressure barometer for detecting weather changes. There is also a sound sensor that detects sound pressure level and peak sound amplitude and a light sensor that can also detect white light levels.

The Sense module enables on-demand or scheduled measurements and provides automatic sensor setup and data analysis, with reports available on a mobile app. Programmable light and sound interrupts are also available.

 
Further information

The Sense module is available starting at 31 Pounds ($39) with shipments due in September. More information may be found on the Sense Kickstarter page and GitHub page, as well as the Metriful website.