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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

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

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
...