Simple program that shows AQI on system tray as a colored pie chart.

aqi_tray.pyw

#!/usr/bin/env python3
"""Simple program that shows AQI on system tray as a colored pie chart.

It fetches PM_2.5 data via Graphite's HTTP API every minutes.

Required Python packages:
    requests, pystray, Pillow
"""
import time
import webbrowser
from typing import Optional
from threading import Thread

from pystray import Icon, Menu, MenuItem
from PIL import Image, ImageDraw
import requests


ICON_SIZE = 32
MARGIN = 1
DRAW_AREA = [MARGIN, MARGIN, ICON_SIZE - MARGIN * 2, ICON_SIZE - MARGIN * 2]
REFRESH_INTERVAL_SECS = 60

# Change the following constants, pointing to your sensors.
WEB_URL = 'https://example.com/grafana/d/YOUR-DASHBOARD/'
GRAPHITE_URL = 'https://example.com/graphite-api/'
TARGET = 'your.sensor.pm25'
FROM = '-5min'

US_AQI = (
    [350.5, 500, 0.66, 501, '#800000', 'Hazardous'],
    [150.5, 350.5, 0.99, 201, '#800080', 'Very Unhealthy'],
    [55.5, 150.5, 0.5185, 151, '#e60000', 'Unhealthy'],
    [35.5, 55.5, 2.45, 101, '#ffa500', 'Unhealthy for Sensitive Groups'],
    [12, 35.5, 2.085, 51, '#e6e600', 'Moderate'],
    [0, 12, 4.1667, 0, '#008000', 'Good']
);  

def create_tray_icon(pm25: Optional[int]=None) -> (Image, str):
    img = Image.new('RGBA', (ICON_SIZE, ICON_SIZE), (0, 0, 0, 0))
    draw = ImageDraw.Draw(img)
    box = [0, 0, ICON_SIZE, ICON_SIZE]

    if pm25 is None:
        color = '#888888'
        deg = 0
        title = 'AQI Unknown'
    else:
        for lower, upper, coe, base, col, category in US_AQI:
            if pm25 > lower:
                color = col
                aqi = (pm25 - lower) * coe + base
                deg = (pm25 - lower) / (upper - lower) * 360
                title = f'AQI {aqi:.0f} - {category}'
                break
    
    draw.pieslice(DRAW_AREA, 0, 360, f'{color}80')
    draw.pieslice(DRAW_AREA, 0, deg, f'{color}ff')
    img = img.rotate(90)
    return img, title


class App:
    def __init__(self):
        self.session = requests.Session()
        img, title = create_tray_icon()
        menu = Menu(
            MenuItem('&Refresh', self.refresh, default=True),
            MenuItem('&Open in browser', self.open_browser),
            Menu.SEPARATOR,
            MenuItem('&Quit', self.quit),
        )
        self.mainloop = Thread(target=self.loop, daemon=True)
        self.icon = Icon("AQI", img, title, menu)
        self.icon.run(setup=lambda _: self.mainloop.start())

    def set_tray_icon(self, pm25: Optional[int]):
        self.icon.icon, self.icon.title = create_tray_icon(pm25)

    def loop(self):
        self.icon.visible = True
        while True:
            try:
                pm25 = self.fetch_pm25()
                self.set_tray_icon(pm25)
            except IOError:
                self.set_tray_icon(None)
            time.sleep(REFRESH_INTERVAL_SECS)

    def refresh(self):
        self.set_tray_icon()
        pm25 = self.fetch_pm25()
        self.set_tray_icon(pm25)
    
    def fetch_pm25(self) -> Optional[int]:
        url = f'{GRAPHITE_URL}render?target={TARGET}&from={FROM}&format=json'
        resp = self.session.get(url)
        if not resp.ok:
            return
        points = [v for v, _ in resp.json()[0]['datapoints'] if v is not None]
        if not points:
            return
        avg = sum(points) / len(points)
        return avg

    def open_browser(self):
        webbrowser.open(WEB_URL)

    def quit(self):
        self.icon.stop()


if __name__ == '__main__':
    App()