Plantower PM2.5 particulate matter sensor script that calculates AQI

pm25.py

import time
import board
import busio
import datetime
from pytz import timezone, utc
import adafruit_pm25

reset_pin = None
# If you have a GPIO, its not a bad idea to connect it to the RESET pin
# This may solve some sensor drift issues over long periods of time (unverified)
# reset_pin = DigitalInOut(board.G0)
# reset_pin.direction = Direction.OUTPUT
# reset_pin.value = False

# For use with a computer running Windows:
# import serial
# uart = serial.Serial("COM30", baudrate=9600, timeout=1)

# For use with microcontroller board:
# (Connect the sensor TX pin to the board/computer RX pin)
# uart = busio.UART(board.TX, board.RX, baudrate=9600)

# For use with Raspberry Pi/Linux:
import serial
uart = serial.Serial("/dev/ttyS0", baudrate=9600, timeout=0.25)

# For use with USB-to-serial cable:
# import serial
# uart = serial.Serial("/dev/ttyUSB0", baudrate=9600, timeout=0.25)

# Connect to a PM2.5 sensor over UART
# pm25 = adafruit_pm25.PM25_UART(uart, reset_pin)

# Create library object, use 'slow' 100KHz frequency!
# i2c = busio.I2C(board.SCL, board.SDA, frequency=100000)

# Connect to a PM2.5 sensor over UART
pm25 = adafruit_pm25.PM25_UART(uart)

liz = [(0, 12, 0, 50),
       (12.1, 35.4, 51, 100),
       (35.5, 55.4, 101, 150),
       (55.5, 150.4, 151, 200),
       (150.5, 250.4, 201, 300),
       (250.5, 350.4, 301, 400),
       (350.5, 500.4, 401, 500)]

def calcAQI(pm25):
  for r in liz:
    (rlo, rhi, lo, hi) = r
    if pm25 >= rlo and pm25 <= rhi:
      return float(hi - lo) / (rhi - rlo) * (pm25 - rlo) + lo

  return float('nan')


letters = { "a":[ "####", "#  #", "####", "#  #", "#  #"], "b":[ "###", "# #", "###", "# #", "###"], "c":[ "###", "#", "#", "#", "###"], "d":[ "##", "# #", "# #", "# #", "##"], "e":[ "###", "#", "###", "#", "###"], "f":[ "###", "#", "###", "#", "#"], "g":[ "###", "# #", "###", "  #", "###"], "h":[ "# #", "# #", "###", "# #", "# #"], "i":[ "###", " #", " #", " #", "###"], "j":[ "###", " #", " #", " #", "##"], "k":[ "# #", "##", "#", "##", "# #"], "l":[ "#", "#", "#", "#", "###"], "m":[ "# #", "###", "###", "# #", "# #"], "n":[ "###", "# #", "# #", "# #", "# #"], "o":[ "###", "# #", "# #", "# #", "###"], "p":[ "###", "# #", "###", "#", "#"], "q":[ "###", "# #", "# #", "# #", "####"], "r":[ "###", "# #", "##", "# #", "# #"], "s":[ "###", "#", "###", "  #", "###"], "t":[ "###", " #", " #", " #", " #"], "u":[ "# #", "# #", "# #", "# #", "###"], "v":[ "# #", "# #", "# #", "# #", " #"], "w":[ "# #", "# #", "# #", "###", "###"], "x":[ "# #", " #", " #", " #", "# #"], "y":[ "# #", "# #", "###", " #", " #"], "z":[ "###", "  #", " #", "#", "###"], " ":[ " "], "1":[ " #", "##", " #", " #", "###"], "2":[ "###", "  #", "###", "#", "###"], "3":[ "###", "  #", "###", "  #", "###"], "4":[ "#  #", "#  #", "####", "   #", "   #"], "5":[ "####", "#", "####", "   #", "####"], "6":[ "###", "#", "###", "# #", "###"], "7":[ "####", "   # ", "  #", "  #", " #"], "8":[ "####", "#  #", "####", "#  #", "####"], "9":[ "###", "# #", "###", "  #", "###"], "0":[ "####", "#  #", "#  #", "#  #", "####"], "!":[ " # ", " # ", " # ", "   ", " # "], "?":[ "###", "  #", " ##", "   ", " # "], ".":[ "   ", "   ", "   ", "   ", " # "], "]":[ "   ", "   ", "   ", "  #", " # "], "/":[ "  #", "  #", " # ", "# ", "# "], ":":[ "   ", " # ", "   ", " # ", "   "], "@":[ "###", "# #", "## ", "#  ", "###"], "'":[ " # ", " # ", "   ", "   ", "   "], "#":[ " # ", "###", " # ", "###", " # "] }

def print_letters(text):
    bigletters = []
    for i in text:
        bigletters.append(letters.get(i.lower(),letters[' ']))
    output = ['']*5
    for i in range(5):
        for j in bigletters:
            temp = ' '
            try:
                temp = j[i]
            except:
                pass
            temp += ' '*(5-len(temp))
            temp = temp.replace(' ',' ')
            temp = temp.replace('#','█')
            output[i] += temp
    return '\n'.join(output)

print("Found PM2.5 sensor, reading data...")

while True:
    try:
        aqdata = pm25.read()
    except RuntimeError as err:
        print(err, "retrying...")
        continue
    print("---------------------------------------")
    date_format = '%Y-%m-%d at %H:%M:%S PST'
    print(datetime.datetime.now(tz=utc).astimezone(timezone('US/Pacific')).strftime(date_format))

    print(print_letters("AQI:%.1f" % calcAQI(aqdata["pm25 standard"])))
       
    #print("Concentration Units (standard)")
    print("PM 1.0: %d\tPM2.5: %d\tPM10: %d" %(aqdata["pm10 standard"], aqdata["pm25 standard"], aqdata["pm100 standard"]))

    # Concentration units (environmental): aqdata["pm10 env"], aqdata["pm25 env"], aqdata["pm100 env"]
    print("Particles > 0.3um / 0.1L air:", aqdata["particles 03um"])
    print("Particles > 0.5um / 0.1L air:", aqdata["particles 05um"])
    print("Particles > 1.0um / 0.1L air:", aqdata["particles 10um"])
    print("Particles > 2.5um / 0.1L air:", aqdata["particles 25um"])
    print("Particles > 5.0um / 0.1L air:", aqdata["particles 50um"])
    print("Particles > 10 um / 0.1L air:", aqdata["particles 100um"])
    print("---------------------------------------")

    time.sleep(3)