Sensirion Raspberry Pi UART SEN44 Driver

This document explains how to set up the SEN44 sensor module 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 SEN44 pinout listed below:

Pin	Name	Description	Comments
1	VDD	Supply Voltage	5V ±10%
2	GND	Ground
3	RX	UART: Receiving pin for communication	TTL 5V and LVTTL 3.3V compatible
	SDA	I2C: Serial data input / output	TTL 5V and LVTTL 3.3V compatible
4	TX	UART: Transmission pin for communication	TTL 5V and LVTTL 3.3V compatible
	SCL	I2C: Serial clock input	TTL 5V and LVTTL 3.3V compatible
5	SEL	Interface select	Leave floating or pull to VDD to select UART
			Pull to GND to select I2C
6	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-sen44

  3. Run the make command to compile the driver

     Output:

     rm -f sen44_uart_example_usage
     cc -Os -Wall -fstrict-aliasing -Wstrict-aliasing=1 -Wsign-conversion -fPIC -I. -o sen44_uart_example_usage sen44_uart.h sen44_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 sen44_uart_example_usage.c
     

• Test your connected sensor

  • Run ./sen44_uart_example_usage in the same directory you used to compile the driver.

    Output:

    Serial number: C081C2651224B6FE
    Firmware: 0.4, Hardware: 6.0, protocol: 2.0
    Mass concentration pm1p0: 1
    Mass concentration pm2p5: 5
    Mass concentration pm4p0: 9
    Mass concentration pm10p0: 11
    Voc index: 0.0
    Ambient humidity: 40.81%RH
    Ambient temperature: 24.58°C
    Mass concentration pm1p0: 1
    Mass concentration pm2p5: 3
    Mass concentration pm4p0: 4
    Mass concentration pm10p0: 4
    Voc index: 0.0
    Ambient humidity: 40.81%RH
    Ambient temperature: 24.58°C
    ...