Sensirion I²C SFX6XXX Arduino Library

This is the Sensirion SFX6XXX library for Arduino allowing you to communicate with a sensor of the SFX6XXX family over I²C.

Click here to learn more about the Sensirion SFX6XXX sensor family.

Supported sensor types

Sensor name	I²C Addresses
SFC6000	0x24, 0x23, 0x22, 0x21, 0x20, 0x42, 0x41
SFC6000D-5SLM	****
SFC6000D-50SLM	****
SFC6000D-20SLM	****
SFM6000	0x24, 0x23, 0x22, 0x21, 0x20, 0x42, 0x41
SFM6000D-20SLM	****
SFM6000D-50SLM	****
SFM6000D-5SLM	****

The following instructions and examples use a SFC6000.

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 SFX6XXX 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 SFX6XXX to the standard I²C bus of your Arduino board:

Pin	Cable Color	Name	Description	Comments
1	red	VDD	Supply Voltage	+24V
2	black	GND	Ground
3		NC	Do not connect
4	yellow	SCL	I2C: Serial clock input
5	purple	ADDR		Leave floating for default i2c address 0x24
6	green	SDA	I2C: Serial data input / output

The recommended voltage is 24V.

Make sure to use pull-up resistors when the used board does not include them in order to ensure a clean I2C signal. Learn more about pull-up resistors here.

Board specific wiring

You will find pinout schematics for recommended board models below:

Arduino Uno

SFX6XXX	SFX6XXX Pin	Cable Color	Board Pin
VDD	1	red	None
GND	2	black	GND
SCL	4	yellow	D19/SCL
ADDR	5	purple
SDA	6	green	D18/SDA

Arduino Nano

SFX6XXX	SFX6XXX Pin	Cable Color	Board Pin
VDD	1	red	None
GND	2	black	GND
SCL	4	yellow	A5
ADDR	5	purple
SDA	6	green	A4

Arduino Micro

SFX6XXX	SFX6XXX Pin	Cable Color	Board Pin
VDD	1	red	None
GND	2	black	GND
SCL	4	yellow	~D3/SCL
ADDR	5	purple
SDA	6	green	D2/SDA

Arduino Mega 2560

SFX6XXX	SFX6XXX Pin	Cable Color	Board Pin
VDD	1	red	None
GND	2	black	GND
SCL	4	yellow	D21/SCL
ADDR	5	purple
SDA	6	green	D20/SDA

ESP32 DevKitC

SFX6XXX	SFX6XXX Pin	Cable Color	Board Pin
VDD	1	red	None
GND	2	black	GND
SCL	4	yellow	GPIO 22
ADDR	5	purple
SDA	6	green	GPIO 21

Quick Start

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

2. Connect the SFX6XXX sensor to your Arduino as explained in Connect the sensor

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

   File ➔ Examples ➔ Sensirion I2C SFX6XXX ➔ exampleUsage

   The provided example is working with a SFC6000, I²C address 0x24. 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/SensirionI2CSFX6XXX.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.

Notes

Implications of 24V power requirement

Since most board do not provide the required 24V, the power will be provided by an external source, therefore the sensor will be unnafected by a board power cycle.

If a measurement is running at the time when a board reset is performed, the sensor will still be measuring when the board starts back up.

That is the reason why the provided example includes a stopContinuousMeasurement() before the call to startO2ContinuousMeasurement(). It will stop a potentially running measurement.

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.