CO2 monitor using Pimoroni Breakout Garden + 5x5 RGB Matrix + SCD41 breakouts, MicroPython 1.21

font2x5fixedmononum.py

# Quick script to convert Adafruit GFX font into binary file.
# Author: Tony DiCola
# License: MIT (https://opensource.org/licenses/MIT)
# Taken from glcdfont.c from Adafruit GFX Arduino library.
FONT = bytes((
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0x00, 0x00,
    0b11111, 0b11111, #0
    0b00000, 0b11111, #1
    0b10111, 0b11101, #2
    0b10101, 0b11111, #3
    0b11100, 0b00111, #4
    0b11101, 0b10111, #5
    0b11111, 0b00111, #6
    0b10000, 0b11111, #7
    0b11011, 0b11011, #8
    0b11100, 0b11111, #9
    0b00000, 0b01010  #:
))


if __name__ == '__main__':
    with open('font2x5.bin', 'wb') as outfile:
        # Write a byte each for the character width, character height.
        outfile.write(bytes((2, 5)))
        # Now write all of the font character bytes.
        for font_byte in FONT:
            outfile.write(font_byte.to_bytes(1, 'big'))

main.py

import utime
from pimoroni import BREAKOUT_GARDEN_I2C_PINS
from pimoroni_i2c import PimoroniI2C
from breakout_rgbmatrix5x5 import BreakoutRGBMatrix5x5
import breakout_scd41
import bitmapfont       # https://github.com/adafruit/micropython-adafruit-bitmap-font

MESSAGE        = '0000'
DISPLAY_WIDTH  = 5      # Display width in pixels.
DISPLAY_HEIGHT = 5       # Display height in pixels.
SPEED          = 5.0    # Scroll speed in pixels per second.
co2 = 0

i2c = PimoroniI2C(**BREAKOUT_GARDEN_I2C_PINS)
matrix = BreakoutRGBMatrix5x5(i2c)
breakout_scd41.init(i2c)
breakout_scd41.start()

with bitmapfont.BitmapFont(5, 5, matrix.set_pixel, 'font2x5.bin') as bf:
    # Global state:
    pos = DISPLAY_WIDTH                 # X position of the message start.
    message_width = bf.width(MESSAGE)   # Message width in pixels.
    last = utime.ticks_ms()             # Last frame millisecond tick time.
    speed_ms = SPEED / 1000.0           # Scroll speed in pixels/ms.
    # Main loop:
    while True:
        # Compute the time delta in milliseconds since the last frame.
        current = utime.ticks_ms()
        delta_ms = utime.ticks_diff(current, last)
        last = current
        
        # Compute position using speed and time delta.
        pos -= speed_ms*delta_ms
        if pos < -message_width:
            pos = DISPLAY_WIDTH
            if breakout_scd41.ready():
                co2, temperature, humidity = breakout_scd41.measure()
                MESSAGE = f'{co2: <4}'  # this is okay because it's a fixed-width font
            
        # Clear the matrix and draw the text at the current position.
        matrix.clear()
        if co2 < 600:
            bf.text(MESSAGE, int(pos), 0, 0, 255, 0)
        elif co2 >= 800:
            bf.text(MESSAGE, int(pos), 0, 255, 0, 000)
        else:
            bf.text(MESSAGE, int(pos), 0, 255, 255, 0)
        # Update the matrix LEDs.
        matrix.update()