linka-firmware-py

A Micropython Library for Linka Air Quality Sensors

Important Note

Micropython doesn't support a Software Serial implementation, so the sensor needs to be connected to the Hardware Serial pins on a ESP8266, this works differently from https://github.com/garyservin/linka-firmware and requires changing the cables on the board if you were using that before. Connection diagram TBA.

Installation

Installing micropython

Download the latest version of micrpython from micropyton.org for your specific board.
Install the flash utility with pip3 install --user esptool
Erase the flash with esptool.py --port /dev/ttyUSB0 erase_flash. You might need to specify a different port depending on your setup.
Flash the micropython firmware with esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect -fm dout 0 MICROPYTHON_FIRWMARE.bin. Replace MICROPYTHON_FIRWMARE.bin with the correct filename.

Create your config file

Create a config file with your custom credentials, it should look like this

config = {
    "ssid": "YOUR_WIFI_SSID",
    "psk": "YOUR_WIFI_PASSWORD",

    "api_key": "YOUR_SUPER_SECRET_API_KEY",

    "latitude": 0.0000,
    "longitude": 0.0000,

    "description": "My Sensor",
}

Other options include

linka_url # if you want to point to a custom backend server, defaults to https://rald-dev.greenbeep.com/api/v1/measurements if not specified
interval # time in seconds to wait before reading and sending a new measuerement

Installing te linka python code

Install the ampy tool pip3 install --user adafuit-ampy
Copy the files to your microcontroller

ampy --port /dev/ttyUSB0 put boot.py
ampy --port /dev/ttyUSB0 put config.py
ampy --port /dev/ttyUSB0 put linka.py
ampy --port /dev/ttyUSB0 put main.py
ampy --port /dev/ttyUSB0 put pms7003.py
ampy --port /dev/ttyUSB0 put webrepl_cfg.py

Restart your board with ampy --port /dev/ttyUSB0 reset
The LED on the board will blink every 5 minutes showing that the board is sending data, if not, you can try to debug it by using a webrepl client like the one included with thonny.

TODO

Add captive portal to more easily configure WiFi credentials
Store data if board isn't connected to the internet to send when connected
Simplify flashing method, add web flashing option
Confirm code works with with ESP32
Confirm code works with Raspberry Pi Pico W
Create wiring diagram