SCD41 CO2 Sensor Breakout (Carbon Dioxide / Temperature / Humidity)

by Pimoroni

A true carbon dioxide sensor that can detect CO2 levels between 400 and 5,000 ppm, mounted on a Breakout Garden and Qw/ST-compatible breakout.

SCD41 is a high accuracy sensor that uses photoacoustic technology to tell you the precise proportion of carbon dioxide (in ppm) of the air that you're breathing. It can also measure temperature and relative humidity.

Too much carbon dioxide has all sorts of unpleasant effects on humans, such as turning up your tiredness levels and turning down your brain power. CO2 build-up is a useful indicator of how well ventilated a space is and also how many people are breathing the same air - a variable that's definitely worth tracking in homes, workplaces and schools at the moment. SCD41 is the extended range variant of this sensor which means it can detect very high levels of CO2 at up to 5,000 ppm, so it could potentially also be useful in industrial and laboratory settings.

We've been testing out this sensor in some of the more confined scuppers and bilges of Pimoroni HQ, and it's remarkable how sensitive it is - you can really see the change in CO2 levels when someone enters or leaves a room, or when doors are open or closed.

This breakout is compatible with our fancy Breakout Garden system, where using breakouts is as easy just popping it into one of the slots and starting to grow your project, create, and code. It's also Qw/ST compatible so it can be plugged into a whole range of different microcontrollers and HATs with Qwiic or STEMMA QT connectors.

Features

  • Sensiron SCD41 carbon dioxide sensor (datasheet)
    • Photoacoustic sensor technology PASens®
    • High accuracy: ±(40 ppm + 5 %)
    • Range: 400 ppm – 5,000 ppm
  • I2C interface, with address: 0x62
  • Qwiic/STEMMA QT connector
  • 3-5V compatible
  • Reverse polarity protection (on Breakout Garden connector)
  • Raspberry Pi-compatible pinout (pins 1, 3, 5, 7, 9)
  • Compatible with Raspberry Pi (Python library)
  • Compatible with Raspberry Pi Pico (C++/MicroPython libraries)
  • Schematic

Kit includes

  • SCD41 breakout
  • 1x5 male header
  • 1x5 female right angle header

We've designed this breakout board so that you can solder on the piece of right angle female header and pop it straight onto the bottom left 5 pins on your Raspberry Pi's GPIO header (pins 1, 3, 5, 7, 9). The right angle header also has the advantage of positioning the breakout away from the Pi's CPU so as to minimise radiated heat.

Software

We've put together a Python library together with examples showing you how to get readings from the sensor. 

You can also use this breakout with Raspberry Pi Pico and other RP2040 boards, using C++ or Pirate brand MicroPython.

Notes

  • Dimensions: approx 24mm x 21mm x 8mm (L x W x H, including sensor)