A minimalist, DIY PurpleAir clone.
Note: This project may go long periods of time without being updated, however it is actively used and maintained. Bug reports and pull requests are welcome.
ClearAir is DIY PurpleAir clone built to be a minimalist replacement. It uses the same sensors and calculations, but for a third of the cost. A Ruby script is provided for reading the current values from the sensor over the network. Other frontends/clients can be written tailored to your needs.
ClearAir was built and tested on an Adafruit Feather M0 WiFi.
- Adafruit Feather M0 WiFi
- Adafruit BME688
- Adafruit PMSA003I
- 5V 1A (1000mA) USB port power supply
- A micro-usb cable
| BME688 | PMSA003I |
|---|---|
| 3V -> 3V | 3V -> 3V |
| GND -> GND | GND -> GND |
| SCL -> SCK | SCL -> SCL |
| SDA -> SDI | SDA -> SDA |
A Fritzing file is located at docs/ClearAir.fzz.
Wiring diagram: 
These instructions are for Linux (x86_64).
- Download and extract the Adafruit SAMD library to
~/.arduino15/packages/adafruit/hardware/samd/1.0.9 - Download and extract the ARM compiler to
~/.arduino15/packages/adafruit/tools/arm-none-eabi-gcc/4.8.3-2014q1 - Download and extract Bossac to
~/.arduino15/packages/adafruit/tools/bossac/1.6.1-arduino. - Download and extract CMSIS to
~/.arduino15/packages/adafruit/tools/CMSIS/4.0.0-atmel.
Note: The archives above can be extracted whenever you'd like, but the paths at the top of the Makefile must be adjusted accordingly.
- Create
src/secrets.hwith the following content:#define _SSID "your_ssid" #define _PASSPHRASE "passphrase" - Edit
src/main.hwith appropriate IP & network settings - Then:
$ make $ make upload
To read values from the device, run ./client.rb [HOST]. Ruby is needed to run this script.
From here other frontends/clients can be written tailored for your needs. Reading from the sensor is as simple as opening a TCP socket and reading the JSON value that is returned.
An example response is as such:
{
"air_quality_index": 9,
"air_quality_category": "Good",
"pm25": 2.00,
"temperature": 23.07,
"humidity": 53.14,
"pressure": 1001.74
}
The default port is 2424. Don't forget to add rules to allow communication on this port on any firewalls or gateways between the client and the server.
Copyright (C) 2021 Shane Tully
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along with this program. If not, see http://www.gnu.org/licenses/.