Carbon dioxide, aka CO2, is a gas that is an essential part of the Earth's atmosphere and life in general. However, while essential, it can have negative effects when concentrations exceed certain level. It can impact the entire planet via global warming. But it can also have very local effects, for example on indoor air quality. Elevated levels of CO2 can lead to reduced cognitive ability and other health related concerns. Therefore, monitoring CO2 levels of inside air can be useful as a part of gauging general air quality. 

Image source:

Numerous projects have already been done to monitor indoor CO2. This project posted to Hackster uses an ESP8266 and a CCS811 to send values to Adafruit IO. This tweet (and also blog post with more info) shares a project done by an 11 year old and is based on the Feather ecosystem using the SCD-30 CO2 sensor from Sensirion. This is an excellent true CO2 concentration sensor which we also use in this project.

In this project we use the SCD-30 along with a Matrix Portal to drive a 64x32 RGB LED matrix. This provides a nice way to display the current conditions and have it be readable to an entire room. And as a bonus, with this hardware arrangement, there is no soldering required!

This project does NOT require any soldering and the matrix is really big so its visible in a classroom, workshop, or on the wall of a home!


Here's a summary of the hardware needed for this project. Some items are optional. Also note that if you purchased an Adabox 016, you will have most of these items already.

The key item is of course the SCD-30 CO2 sensor itself:

Video of someone blowing a dust on a Adafruit SCD-30 - NDIR CO2 Temperature and Humidity Sensor.
Take a deep breath slowly breathe out. Mmm isn't it wonderful? All that air around us, which we bring into our lungs, extracts oxygen from and then breathes out carbon...
In Stock

To provide a solderless way to connect the SCD-30 to the Matrix Portal, you can use a STEMMA QT cable. They come in various lengths:

Angled of of JST SH 4-Pin Cable.
This 4-wire cable is 50mm / 1.9" long and fitted with JST SH female 4-pin connectors on both ends. Compared with the chunkier JST PH these are 1mm pitch instead of 2mm, but...
In Stock
Angled shot of STEMMA QT / Qwiic JST SH 4-pin Cable.
This 4-wire cable is a little over 100mm / 4" long and fitted with JST-SH female 4-pin connectors on both ends. Compared with the chunkier JST-PH these are 1mm pitch instead of...
Out of Stock
Angled shot of JST SH 4-Pin Cable - 200mm Long.
This 4-wire cable is a little over 200mm / 7.8" long and fitted with JST-SH female 4-pin connectors on both ends. Compared with the chunkier JST-PH these are 1mm pitch instead of...
Out of Stock

You'll also need a 64x32 LED matrix and a Matrix Portal to drive the matrix:

Video of a person rotating an LED matrix panel with animation resembling falling colored sand.
Folks love our wide selection of RGB matrices and accessories, for making custom colorful LED displays... and our RGB Matrix Shields...
In Stock
Vide of assembled and powered on 64x32 RGB LED Matrix Panel - 4mm pitch. The matrix displays "Black Lives Matter" alongside the Raised Fist.
Bring a little bit of Times Square into your home with this sweet 64 x 32 square RGB LED matrix panel. These panels are normally used to make video walls, here in New York we see them...
In Stock

OPTIONAL. You can add one of these acrylic diffusers to provide a more matted look to the display:

LED RGB matrix 10.2" x 5.1" with "Adafruit Industries LED Matrix" text showing, and LED acrylic slowly covering to make it nicely diffused
 nice whoppin' rectangular slab of some lovely black acrylic to add some extra diffusion to your LED Matrix project. This material is 2.6mm (0.1") thick and is made of...
In Stock

This guide was first published on Feb 02, 2021. It was last updated on Feb 27, 2024.

This page (Overview) was last updated on Feb 01, 2021.

Text editor powered by tinymce.