Here's how to load the code and assets as well as some additional libraries you'll need.
Additional Libraries
To use with CircuitPython, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.
Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory Matrix_Portal_CO2_Monitor/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.
CIRCUITPY
# SPDX-FileCopyrightText: 2021 Carter Nelson for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import time
import board
import displayio
import adafruit_imageload
from adafruit_matrixportal.matrix import Matrix
import adafruit_scd30
# --| User Config |----
CO2_CUTOFFS = (1000, 2000, 5000)
UPDATE_RATE = 1
# ---------------------
# the sensor
i2c = board.I2C() # uses board.SCL and board.SDA
# i2c = board.STEMMA_I2C() # For using the built-in STEMMA QT connector on a microcontroller
scd30 = adafruit_scd30.SCD30(i2c)
# optional if known (pick one)
# scd30.ambient_pressure = 1013.25
# scd30.altitude = 0
# the display
matrix = Matrix(width=64, height=32, bit_depth=6)
display = matrix.display
display.rotation = 90 # matrixportal up
# display.rotation = 270 # matrixportal down
# current condition smiley face
smileys_bmp, smileys_pal = adafruit_imageload.load("/bmps/smileys.bmp")
smiley = displayio.TileGrid(
smileys_bmp,
pixel_shader=smileys_pal,
x=0,
y=0,
width=1,
height=1,
tile_width=32,
tile_height=32,
)
# current condition label
tags_bmp, tags_pal = adafruit_imageload.load("/bmps/tags.bmp")
label = displayio.TileGrid(
tags_bmp,
pixel_shader=tags_pal,
x=0,
y=32,
width=1,
height=1,
tile_width=32,
tile_height=16,
)
# current CO2 value
digits_bmp, digits_pal = adafruit_imageload.load("/bmps/digits.bmp")
co2_value = displayio.TileGrid(
digits_bmp,
pixel_shader=digits_pal,
x=0,
y=51,
width=4,
height=1,
tile_width=8,
tile_height=10,
)
# put em all together
splash = displayio.Group()
splash.append(smiley)
splash.append(label)
splash.append(co2_value)
# and show em
display.root_group = splash
def update_display(value):
value = abs(round(value))
# smiley and label
if value < CO2_CUTOFFS[0]:
smiley[0] = label[0] = 0
elif value < CO2_CUTOFFS[1]:
smiley[0] = label[0] = 1
elif value < CO2_CUTOFFS[2]:
smiley[0] = label[0] = 2
else:
smiley[0] = label[0] = 3
# CO2 value
# clear it
for i in range(4):
co2_value[i] = 10
# update it
i = 3
while value:
co2_value[i] = value % 10
value = int(value / 10)
i -= 1
while True:
# protect against NaNs and Nones
try:
update_display(scd30.CO2)
except:
pass
time.sleep(UPDATE_RATE)
Page last edited February 24, 2025
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