Get started with the Environmental Sensor Board

The Environmental Sensor Board is an add-on board (also known as a pHAT or bonnet) that adds sensing capabilities to your Coral Dev Board or Raspberry Pi projects. It includes a secure cryptoprocessor with Google keys to enable connectivity with Google Cloud IoT Core services, allowing you to securely connect to the device and then collect, process, and analyze the sensor data.

This page is your guide to get started with the board. You can choose to connect the board to either the Coral Dev Board or any Raspberry Pi with a 40-pin header. Then you can collect sensor data using our Python API.

However, if you plan to process the data from your Environmental Sensor using a cloud backend, then instead try getting started with the Google Cloud tutorial called Sensor data collection and analytics with Cloud IoT Core.

Attach the sensor board

Whether you're using the Coral Dev Board or a Raspberry Pi, the Environmental Sensor Board must attach to the 40-pin header so that the sensor board is oriented directly above the host board. If you're using the Dev Board, this requires a header extension so the board can clear the heat sink/fan. For example, see this extra tall header from Adafruit, which gives enough room for the Dev Board fan to breathe.

If you're using a Raspberry Pi, you can now power on your board. The sensor board includes an EEPROM that allows the Raspberry Pi to automatically apply the device tree that configures all the header pins.

If you're using a Dev Board, the device tree is not automatically applied, so you must first power the board and perform the following steps from the Dev Board shell (be sure you're connected to the internet):

  1. Download our device tree for the sensor board and write it to /boot/coral-enviro-board.dtbo as follows:

    curl "https://coral.googlesource.com/coral-cloud/+/refs/heads/master/coral-enviro-devicetree/coral-enviro-board.dtbo?format=TEXT" \
    | base64 --decode | sudo tee /boot/coral-enviro-board.dtbo > /dev/null
    
  2. Add the new device tree to the overlays file:

    sudo sed -i '$ s/$/ coral-enviro-board/' /boot/overlays.txt
    

This overlay will apply once you reboot your board, but you need to install the Python library first.

Install the Python library

On your Dev Board or Raspberry Pi, run the following commands to install the Environmental Sensor Board library and driver:

echo "deb https://packages.cloud.google.com/apt coral-cloud-stable main" | sudo tee /etc/apt/sources.list.d/coral-cloud.list

curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

sudo apt update

sudo apt upgrade

sudo apt install python3-coral-enviro

Now reboot to apply the overlay and enable the sensor board driver:

sudo reboot now

Try the demo

We've provided a sample script that prints data from the temperature, humidity, ambient light, and pressure sensors onto the board's OLED display. You can run it as follows:

cd /usr/lib/python3/dist-packages/coral/enviro

# On Raspberry Pi:
python3 enviro_demo.py

# On Dev Board (root is required for GPIO control):
sudo python3 enviro_demo.py

Now look at the board's display to see the sensor data.

You can browse the sample code here.

Also take a look at the API documentation for coral.enviro.board and coral.cloudiot.core.

For more information about connecting your application to the cloud, see the Cloud IoT Core documentation. Also checkout the complete tutorial about sensor data collection and analytics with Cloud IoT Core.