Air quality monitor using the Open Book and Adafruit PMSA003I Air Quality Breakout

lineplot.py

import displayio
from adafruit_display_text.label import Label

class LinePlot(displayio.Group):
    def __init__(
        self,
        font,
        *,
        x=0,
        y=0,
        width=300,
        height=200,
        color=0xFFFFFF,
        **kwargs
    ):
        super().__init__(max_size=5, **kwargs)
        self.x = x
        self.y = y
        self.width = width
        self.height = height
        self.color = color
        self._palette = displayio.Palette(2)
        self._palette[0] = 0
        self._palette.make_transparent(0)
        self._palette[1] = color
        char_width = font.get_glyph(ord("M")).width
        char_height = font.get_glyph(ord("M")).height
        self._label_ymax = Label(font, x=0, y=0, max_glyphs=5, color=color)
        self._label_ymin = Label(font, x=0, y=height - char_height, max_glyphs=5, color=color)
        self._plot_image = displayio.Bitmap(width - 5 * char_width, height, 2)
        self._plot_origin_x = 5 * char_width
        self.max_values = self._plot_image.width - 1
        self.values = [0] * self.max_values
        self._plot_added = False
        self.draw_plot()

        self.append(self._label_ymax)
        self.append(self._label_ymin)
        
    def push_value(self, value):
        self.values.pop(0)
        self.values.append(value)
        self.draw_plot()

    def draw_plot(self):
        self._plot_image.fill(0)
        for x in range(0, self._plot_image.width):
            self._plot_image[x, self._plot_image.height - 1] = 1
        for y in range(0, self._plot_image.height):
            self._plot_image[0, y] = 1
        ymin = min(self.values)
        ymax = max(self.values)
        self._label_ymax.text = f"{ymax:5}"
        self._label_ymin.text = f"{ymin:5}"

        if ymin != ymax:
            for i in range(0, len(self.values)):
                scaled_value = self._plot_image.height - 1 - round((float(self.values[i] - ymin) / float(ymax - ymin)) * float(self._plot_image.height - 1))
                self._plot_image[i + 1, int(scaled_value)] = 1
        if self._plot_added:
            self.pop(0)
        plot = displayio.TileGrid(self._plot_image, pixel_shader=self._palette, x=self._plot_origin_x, y=0)
        self.insert(0, plot)
        self._plot_added = True
        

main.py

import time
import board
import busio
from digitalio import DigitalInOut, Direction, Pull
from analogio import AnalogIn
import adafruit_pm25
import displayio
import terminalio
from adafruit_display_text.label import Label
from lineplot import LinePlot

display = board.DISPLAY

# air quality sensor
i2c = busio.I2C(board.SCL, board.SDA, frequency=100000)
pm25 = adafruit_pm25.PM25_I2C(i2c)

# power monitors
vbat = AnalogIn(board.BATTERY)
vbus = AnalogIn(board.USB)

ui = displayio.Group(max_size=16)

title_label = Label(terminalio.FONT, x=6, y=4, max_glyphs=48, color=0xFFFFFF)
ui.append(title_label)

white_bitmap = displayio.Bitmap(300, 376, 1)
white_palette = displayio.Palette(1)
white_palette[0] = 0xFFFFFF
background = displayio.TileGrid(white_bitmap, pixel_shader=white_palette, x=0, y=24)
ui.append(background)

plots = list()
particles = [0.3, 0.5, 1, 2.5, 5, 10]
for i in range(0, len(particles)):
    label = Label(terminalio.FONT, x=0, y=56 + i * 63, text="> {}um\n  /dL".format(particles[i]), color=0, line_spacing=0.75)
    plot = LinePlot(terminalio.FONT, x=20, y=27 + i * 63, width=280, height=58, color=0)
    plots.append(plot)
    ui.append(label)
    ui.append(plot)

display.show(ui)

while True:
    title_label.text = f"Air Quality Monitor     VBat: {2 * 3.3 * vbat.value / 65535:4.3}V  VBus: {2 * 3.3 * vbus.value / 65535:4.3}V"

    try:
        aqdata = pm25.read()
        print(aqdata)
    except RuntimeError:
        print("Unable to read from sensor, retrying...")
        continue

    plots[0].push_value(aqdata["particles 03um"])
    plots[1].push_value(aqdata["particles 05um"])
    plots[2].push_value(aqdata["particles 10um"])
    plots[3].push_value(aqdata["particles 25um"])
    plots[4].push_value(aqdata["particles 50um"])
    plots[5].push_value(aqdata["particles 100um"])
    display.refresh()
    time.sleep(10)