Sensirion Raspberry Pi UART SFA3x Driver

This document explains how to set up the SEK-SFA3x evaluation kit to run on a Raspberry Pi using the provided code.

Setup Guide

Connecting the Sensor

Plug the provided USB cable into your Raspberry Pi.

If you don't have a suitable cable at hand, please find the SEK-SFA3x pinout listed below, or in the datasheet:

Pin	Name	Description	Comments
1	VDD	Supply Voltage	5V ±10%
2	GND	Ground
3	RX	UART: Receiving pin for communication
	SDA	I2C: Serial data input / output
4	TX	UART: Transmission pin for communication
	SCL	I2C: Serial clock input
5	SEL	Interface select	Leave floating or pull to VDD to select UART
			Pull to GND to select I2C
6	NC	Do not connect
7	NC	Do not connect

Raspberry Pi

• Install the Raspberry Pi OS on to your Raspberry Pi

• Download the driver from the Sensirion GitHub Page and extract the .zip on your Raspberry Pi

• Compile the driver

  1. Open a terminal

  2. Navigate to the driver directory. E.g. cd ~/raspberry-pi-uart-sfa3x

  3. Run the make command to compile the driver

     Output:

     rm -f sfa3x_uart_example_usage
     cc -Os -Wall -fstrict-aliasing -Wstrict-aliasing=1 -Wsign-conversion -fPIC -I. -o sfa3x_uart_example_usage sfa3x_uart.h sfa3x_uart.c sensirion_uart_hal.h sensirion_shdlc.h sensirion_shdlc.c \
      sensirion_uart_hal.c sensirion_config.h sensirion_common.h sensirion_common.c sfa3x_uart_example_usage.c
     

• Test your connected sensor

  • Run ./sfa3x_uart_example_usage in the same directory you used to compile the driver.

    Output:

    Device marking: 494108010320N020234S
    Formaldehyde concentration: 0.0 ppb
    Relative humidity: 35.35 %RH
    Temperature: 25.28 °C
    Formaldehyde concentration: 0.0 ppb
    Relative humidity: 35.34 %RH
    Temperature: 25.26 °C
    Formaldehyde concentration: 0.0 ppb
    Relative humidity: 35.36 %RH
    Temperature: 25.28 °C
    Formaldehyde concentration: 0.0 ppb
    Relative humidity: 35.34 %RH
    Temperature: 25.28 °C
    ...