Zephyr Examples

The Air Quality Wing has first class support on Zephyr. It can be used with almost any board that is supported by Zephyr.

Here's the code.

Sample descriptions

The code is a a work in progress but includes a BLE example, nRF9160 Feather example an standalone sample.

Basic

The Basic example connects to and obtain samples on a regular basis. They're printed out to the console.

BLE (Bluetooth Low Energy)

The BLE example does the same as the Basic but also connectable via Bluetooth. Once connected characteristics can be subscribed to and updated by the device.

Golioth

The Golioth example is the same as Basic but it also publishes to the Golioth IoT backend for integration with tools like Grafana.

Setting up your environment

Here is the minimal amount of steps to get an example working. This example is currently only configured for the nRF52 DK.

Hardware

If you do not have a PM2.5 sensor you can comment out &hpma_sensor, within sensors[] in main.c before building.

Virtual Environment

One of the main dependencies for Zephyr is Python. Instead of installing the required packages directly to your system, I highly recommend use a virtual environment instead.

First lets make a project folder. We can call it aqw:

mkdir -p aqw

If you don't have virtualenv installed already, make sure you install it:

pip3 install virtualenv

Set up a python virtual environment:

virtualenv -p python3 env

Then enable it by running:

source env/bin/activate

Install west

west is the command line utility for Zephyr. You'll need it to build the firmware.

pip3 install west

Init and update project

Next we'll download the source code and install the dependencies.

west init -m https://github.com/circuitdojo/air-quality-wing-zephyr-demo.git  --manifest-rev main

Or already cloned locally:

west init -l .

Then run

west update

This will download all the dependencies. If there are ever fixes to this sample you'll need to pull the changes and then re-run west update:

git pull && west update

Install remaining python dependencies

Finally, there are some important dependencies needed to build your freshly cloned Zephyr repository. Let's install those here.

pip3 install -r zephyr/scripts/requirements.txt

Install toolchain

• For Mac run the following: (it does require you install wget. brew is an easy way to do so: brew install wget)

  cd ~
  wget "https://developer.arm.com/-/media/Files/downloads/gnu-rm/9-2019q4/gcc-arm-none-eabi-9-2019-q4-major-mac.tar.bz2"
  tar xvfj gcc-arm-none-eabi-9-2019-q4-major-mac.tar.bz2
  rm gcc-arm-none-eabi-9-2019-q4-major-mac.tar.bz2
  

  Note for Catalina users you will get an error when running these utilities for the first time. You must allow them to be executed in your Security preferences.

  

• For Windows you can download and install the toolchain with this direct link.

Golioth

You will need to edit golioth.conf with your credentials in order to connect to Golioth's backend. More instructions on setting up your credentials can be found here. You can also create devices and add credentials within the Golioth Console.

Building

nRF52840 DK

cd demo
west build -b nrf52840dk_nrf52840

Then flash using

nrfjprog --program build/merged.hex --chiperase --reset

or load via the bootloader

newtmgr -c serial image upload build/zephyr/app_update.bin && newtmgr -c serial reset

Xenon

cd basic
west build -b particle_xenon

Then flash using

nrfjprog --program build/merged.hex --chiperase --reset

nRF9160 Feather

cd basic
west build -b circuitdojo_feather_nrf9160_ns

Then flash using

nrfjprog --program build/merged.hex --chiperase --reset