Example Code for Raspberry Pi-Read VOC Index

Hardware Preparation

• Raspberry Pi B4(or similar) x 1
• Gravity: SGP40 Air Quality Sensor x1
• Jumper wires

Software Preparation

• SGP40 Air Quality Sensor Python Library
• RASPBIAN Raspberry Pi Official OS

Wiring Diagram

Other Preparation Work

Step 1. Enable Raspberry Pi I2C. Skip this step if it is already enabled. Open the terminal, input the following commands:

pi@raspberrypi:~ $ sudo raspi-config

Select "5 Interfacing Options" with the up/down arrows, press "enter", then select "P5 I2C", click "YES". Restart the Raspberry Pi board.

Step 2. Install Python Dependent Library and git(Your Raspberry Pi board needs to access to the Internet). Skip this step if they have been installed already. Input the following commands into the terminal:

pi@raspberrypi:~ $ sudo apt-get update
pi@raspberrypi:~ $ sudo apt-get install build-essential python-dev python-smbus git

Step 3. Download SGP40 Driver library. Input the following commands into the terminal:

pi@raspberrypi:~ $ cd Desktop
pi@raspberrypi:~/Desktop $ git clone https://github.com/DFRobot/DFRobot_SGP40

Sample Code

• Connect the sensor with your Raspberry Pi board as the diagram shown above. I2C default address: 0x59.

• Input the following commands into the terminal and run the codes:

pi@raspberrypi:~/Desktop $ cd /home/pi/Desktop/DFRobot_SGP40/Python/raspberrypi/examples/
pi@raspberrypi:~/Desktop/DFRobot_SGP40/Python/raspberrypi/examples $ python get_voc_index.py

Result

Additional Information

The sensor provides the change of air quality trend, and the algorithm will continuously adjust the baseline of typical air according to historical data. The longer the sensor is used, the better the sensitivity and accuracy of trend and change.

In the normal air environment, the sensor can obtain the accurate VOC index immediately after use; in the heavily-polluted environment, the sensor can obtain the accurate VOC index after use for about 1 hour. It is recommended to integrate it into the long-term indoor projects.