sensirion / raspberry-pi-uart-sfa3x

RaspberryPi driver for Sensirion SFA3x sensor module

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
    ...
    

raspberry-pi-uart-sfa3x's Issues

HCHO always zero

Hi, I just received the SFA30 evaluation kit and I ran the code with a raspberry pi for about 8 hours.

Temperature and humidity is correct but HCHO only gives zero:

This is measured in a relatively new office building. At the same time, I also have the SGP30 sensor that shows readings above 100 ppb (the broad peaks are during night when I suspect ventilation is off).

I also have a BME680 sensor and it reports very high bVOCe, in the range of 5000 ppb.

Do you have any thoughts on which of the three scenarios could be happening?

1. The air is completely devoid of formaldehyde?
2. The software in this repo contains a bug?
3. Hardware failure (keeping in mind that the software does not report any error codes..)?