Sensirion I²C SCD4X Arduino Library

This is the Sensirion SCD4X library for Arduino allowing you to communicate with a sensor of the SCD4X family over I²C.

Click here to learn more about the Sensirion SCD4X sensor family.

Not all sensors of this driver family support all measurements. In case a measurement is not supported by all sensors, the products that support it are listed in the API description.

Supported sensor types

Sensor name	I²C Addresses
SCD40	0x62
SCD41	0x62

The following instructions and examples use a SCD41.

Installation of the library

This library can be installed using the Arduino Library manager: Start the Arduino IDE and open the Library Manager via

Sketch ➔ Include Library ➔ Manage Libraries...

Search for the Sensirion I2C SCD4X library in the Filter your search... field and install it by clicking the install button.

If you cannot find it in the library manager, download the latest release as .zip file and add it to your Arduino IDE via

Sketch ➔ Include Library ➔ Add .ZIP Library...

Don't forget to install the dependencies listed below the same way via library manager or Add .ZIP Library

Dependencies

• Sensirion Core

Connect the sensor

Use the following pin description to connect your SCD4X to the standard I²C bus of your Arduino board:

Pin	Cable Color	Name	Description	Comments
1	yellow	SCL	I2C: Serial clock input
2	black	GND	Ground
3	red	VDD	Supply Voltage	2.4V to 5.5V
4	green	SDA	I2C: Serial data input / output

The recommended voltage is 3.3V.

Board specific wiring

You will find pinout schematics for recommended board models below:

Arduino Uno

SCD4X	SCD4X Pin	Cable Color	Board Pin
SCL	1	yellow	D19/SCL
GND	2	black	GND
VDD	3	red	3.3V
SDA	4	green	D18/SDA

Arduino Nano

SCD4X	SCD4X Pin	Cable Color	Board Pin
SCL	1	yellow	A5
GND	2	black	GND
VDD	3	red	3.3V
SDA	4	green	A4

Arduino Micro

SCD4X	SCD4X Pin	Cable Color	Board Pin
SCL	1	yellow	~D3/SCL
GND	2	black	GND
VDD	3	red	3.3V
SDA	4	green	D2/SDA

Arduino Mega 2560

SCD4X	SCD4X Pin	Cable Color	Board Pin
SCL	1	yellow	D21/SCL
GND	2	black	GND
VDD	3	red	3.3V
SDA	4	green	D20/SDA

ESP32 DevKitC

SCD4X	SCD4X Pin	Cable Color	Board Pin
SCL	1	yellow	GPIO 22
GND	2	black	GND
VDD	3	red	3V3
SDA	4	green	GPIO 21

Quick Start

1. Install the libraries and dependencies according to Installation of the library

2. Connect the SCD4X sensor to your Arduino as explained in Connect the sensor

3. Open the exampleUsage sample project within the Arduino IDE:

   File ➔ Examples ➔ Sensirion I2C SCD4X ➔ exampleUsage

   The provided example is working with a SCD41, I²C address 0x62. In order to use the code with another product or I²C address you need to change it in the code of examples/exampleUsage. You find the list with pre-defined addresses in src/SensirionI2CSCD4X.h.

4. Click the Upload button in the Arduino IDE or Sketch ➔ Upload

5. When the upload process has finished, open the Serial Monitor or Serial Plotter via the Tools menu to observe the measurement values. Note that the Baud Rate in the used tool has to be set to 115200 baud.

Contributing

Contributions are welcome!

This Sensirion library uses clang-format to standardize the formatting of all our .cpp and .h files. Make sure your contributions are formatted accordingly:

The -i flag will apply the format changes to the files listed.

clang-format -i src/*.cpp src/*.h

Note that differences from this formatting will result in a failed build until they are fixed. :

License

See LICENSE.