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Sensirion Raspberry Pi I2C SVM4x Driver

This document explains how to set up the SEK-SVM4x sensor module to run on a Raspberry Pi using the provided code.

The SVM4x evaluation kit covers evaluation of the SGP40 and SGP41 sensors.

Setup Guide

Connecting the Sensor

Your sensor has the five different connectors: VCC, GND, SDA, SCL, SEL (the sixth connector will not be used for now). Use the following pins to connect your SVM4x:

SVM4x	Raspberry Pi	Jumper Wire
VCC	Pin 1 or 2 (3.3V or 5V)	Red
GND	Pin 6	Black
SDA	Pin 3	Green
SCL	Pin 5	Yellow
SEL	Pin 9 (GND for I2C)	Blue

If you don't have a suitable cable at hand, please find the SEK-SVM4x technical description here:

Pin	Cable Color	Name	Description	Comments
1	Red	VDD	Supply Voltage	3.3 or 5.0 V
2	Black	Ground
3	Green	RX	UART: Receiving pin for communication
		SDA	I2C: Serial data, bidirectional
4	Yellow	TX	UART: Transmission pin for communication
		SCL	I2C: Serial clock
5	Blue	SEL	Interface select	Leave floating or pull to VDD to select UART
				Pull to GND to select I2C
6	Purple	NC	Do not connect

Raspberry Pi

Install the Raspberry Pi OS on to your Raspberry Pi
Enable the I2C interface in the raspi-config
Download the driver for 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-i2c-svm4x

Run the make command to compile the driver

Output:

rm -f svm41_i2c_example_usage
cc -Os -Wall -fstrict-aliasing -Wstrict-aliasing=1 -Wsign-conversion -fPIC -I. -o svm41_i2c_example_usage  svm41_i2c.h svm41_i2c.c sensirion_i2c_hal.h sensirion_i2c.h sensirion_i2c.c \
  sensirion_i2c_hal.c sensirion_config.h sensirion_common.h sensirion_common.c svm41_i2c_example_usage.c

Test your connected sensor

Run ./svm41_i2c_example_usage in the same directory you used to compile the driver.

Output:

Serial number: 0FA3F1F7000003392A3D0240
Firmware: 3.0 Debug: 0
Hardware: 3.0
Protocol: 1.0
Temperature Offset: 0.00 °C
Humidity: 47.34 % RH
Temperature: 28.95 °C
VOC index: 101.0 VOC index
NOx index: 1.0 NOx index
Humidity: 47.35 % RH
Temperature: 28.98 °C
VOC index: 101.0 VOC index
NOx index: 1.0 NOx index
...

Troubleshooting

Initialization failed

Ensure that you connected the sensor correctly: All cables are fully plugged in and connected to the correct pin.
Ensure that I2C is enabled on the Raspberry Pi. For this redo the steps on "Enable the I2C interface in the raspi-config" in the guide above.
Ensure that your user account has read and write access to the I2C device. If it only works with user root (sudo ./svm41_i2c_example_usage), it's typically due to wrong permission settings.