Installing Project Code

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 literary-clock/ and then click on the directory that matches the version of CircuitPython you're using.

Connect your MagTag board to your computer via a known good USB data+power cable. The board should show up as a thumb drive named CIRCUITPY in Explorer or Finder (depending on your operating system). Copy the contents of that directory to your CIRCUITPY drive.

Your CIRCUITPY drive should now look similar to the following image:

CIRCUITPY
# SPDX-FileCopyrightText: 2022 Eva Herrada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time

import ssl
import gc
import socketpool
import wifi
import adafruit_minimqtt.adafruit_minimqtt as MQTT
from adafruit_io.adafruit_io import IO_MQTT
import adafruit_datetime
import adafruit_display_text
from adafruit_display_text import label
import board
from adafruit_bitmap_font import bitmap_font
import displayio
from adafruit_display_shapes.rect import Rect

UTC_OFFSET = -4

quotes = {}
with open("quotes.csv", "r", encoding="UTF-8") as F:
    for quote_line in F:
        split = quote_line.split("|")
        quotes[split[0]] = split[1:]

display = board.DISPLAY
splash = displayio.Group()
display.root_group = splash

arial = bitmap_font.load_font("fonts/Arial-12.pcf")
bold = bitmap_font.load_font("fonts/Arial-Bold-12.pcf")
LINE_SPACING = 0.8
HEIGHT = arial.get_bounding_box()[1]
QUOTE_X = 10
QUOTE_Y = 7

rect = Rect(0, 0, 296, 128, fill=0xFFFFFF, outline=0xFFFFFF)
splash.append(rect)

quote = label.Label(
    font=arial,
    x=QUOTE_X,
    y=QUOTE_Y,
    color=0x000000,
    line_spacing=LINE_SPACING,
)

splash.append(quote)
time_label = label.Label(
    font=bold,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(time_label)

time_label_2 = label.Label(
    font=bold,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(time_label_2)

after_label = label.Label(
    font=arial,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(after_label)

after_label_2 = label.Label(
    font=arial,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(after_label_2)

author_label = label.Label(
    font=arial, x=QUOTE_X, y=115, color=0x000000, line_spacing=LINE_SPACING
)
splash.append(author_label)

try:
    from secrets import secrets
except ImportError:
    print("WiFi secrets are kept in secrets.py, please add them there!")
    raise

aio_username = secrets["aio_username"]
aio_key = secrets["aio_key"]

print(f"Connecting to {secrets['ssid']}")
wifi.radio.connect(secrets["ssid"], secrets["password"])
print(f"Connected to {secrets['ssid']}!")


def get_width(font, text):
    return sum(font.get_glyph(ord(c)).shift_x for c in text)


def smart_split(text, font, width):
    words = ""
    spl = text.split(" ")
    for i, word in enumerate(spl):
        words += f" {word}"
        lwidth = get_width(font, words)
        if width + lwidth > 276:
            spl[i] = "\n" + spl[i]
            text = " ".join(spl)
            break
    return text


def connected(client):  # pylint: disable=unused-argument
    io.subscribe_to_time("iso")


def disconnected(client):  # pylint: disable=unused-argument
    print("Disconnected from Adafruit IO!")


def update_text(hour_min):
    quote.text = (
        time_label.text
    ) = time_label_2.text = after_label.text = after_label_2.text = ""

    before, time_text, after = quotes[hour_min][0].split("^")
    text = adafruit_display_text.wrap_text_to_pixels(before, 276, font=arial)
    quote.text = "\n".join(text)

    for line in text:
        width = get_width(arial, line)

    time_text = smart_split(time_text, bold, width)

    split_time = time_text.split("\n")
    if time_text[0] != "\n":
        time_label.x = time_x = QUOTE_X + width
        time_label.y = time_y = QUOTE_Y + int((len(text) - 1) * HEIGHT * LINE_SPACING)
        time_label.text = split_time[0]
    if "\n" in time_text:
        time_label_2.x = time_x = QUOTE_X
        time_label_2.y = time_y = QUOTE_Y + int(len(text) * HEIGHT * LINE_SPACING)
        wrapped = adafruit_display_text.wrap_text_to_pixels(
            split_time[1], 276, font=arial
        )
        time_label_2.text = "\n".join(wrapped)
    width = get_width(bold, split_time[-1]) + time_x - QUOTE_X

    if after:
        after = smart_split(after, arial, width)

        split_after = after.split("\n")
        if after[0] != "\n":
            after_label.x = QUOTE_X + width
            after_label.y = time_y
            after_label.text = split_after[0]
        if "\n" in after:
            after_label_2.x = QUOTE_X
            after_label_2.y = time_y + int(HEIGHT * LINE_SPACING)
            wrapped = adafruit_display_text.wrap_text_to_pixels(
                split_after[1], 276, font=arial
            )
            after_label_2.text = "\n".join(wrapped)

    author = f"{quotes[hour_min][2]} - {quotes[hour_min][1]}"
    author_label.text = adafruit_display_text.wrap_text_to_pixels(
        author, 276, font=arial
    )[0]
    time.sleep(display.time_to_refresh + 0.1)
    display.refresh()


LAST = None


def message(client, feed_id, payload):  # pylint: disable=unused-argument
    global LAST  # pylint: disable=global-statement
    timezone = adafruit_datetime.timezone.utc
    timezone._offset = adafruit_datetime.timedelta(  # pylint: disable=protected-access
        seconds=UTC_OFFSET * 3600
    )
    datetime = adafruit_datetime.datetime.fromisoformat(payload[:-1]).replace(
        tzinfo=timezone
    )
    local_datetime = datetime.tzinfo.fromutc(datetime)
    print(local_datetime)
    hour_min = f"{local_datetime.hour:02}:{local_datetime.minute:02}"
    if local_datetime.minute != LAST:
        if hour_min in quotes:
            update_text(hour_min)

    LAST = local_datetime.minute
    gc.collect()


# Create a socket pool
pool = socketpool.SocketPool(wifi.radio)

# Initialize a new MQTT Client object
mqtt_client = MQTT.MQTT(
    broker="io.adafruit.com",
    port=1883,
    username=secrets["aio_username"],
    password=secrets["aio_key"],
    socket_pool=pool,
    ssl_context=ssl.create_default_context(),
)

# Initialize an Adafruit IO MQTT Client
io = IO_MQTT(mqtt_client)

# Connect the callback methods defined above to Adafruit IO
io.on_connect = connected
io.on_disconnect = disconnected
io.on_message = message

# Connect to Adafruit IO
print("Connecting to Adafruit IO...")
io.connect()

while True:
    try:
        io.loop()
    except (ValueError, RuntimeError) as e:
        print("Failed to get data, retrying\n", e)
        wifi.reset()
        io.reconnect()
        continue
    time.sleep(1)

Code run-through

The code starts out by importing all the libraries it needs - quite a lot in this case.

import time

import ssl
import gc
import socketpool
import wifi
import adafruit_minimqtt.adafruit_minimqtt as MQTT
from adafruit_io.adafruit_io import IO_MQTT
import adafruit_datetime
import adafruit_display_text
from adafruit_display_text import label
import board
from adafruit_bitmap_font import bitmap_font
import displayio
from adafruit_display_shapes.rect import Rect

Then, it sets the UTC offset - you should modify this to your current local UTC offset (you can find that here: https://www.timeanddate.com/time/zone/timezone/utc).

It then imports the quotes file and starts to set up the display and fonts.

UTC_OFFSET = -4

quotes = {}
with open("quotes.csv", "r", encoding="UTF-8") as F:
    for quote_line in F:
        split = quote_line.split("|")
        quotes[split[0]] = split[1:]

display = board.DISPLAY
splash = displayio.Group()
display.root_group = splash

arial = bitmap_font.load_font("fonts/Arial-12.pcf")
bold = bitmap_font.load_font("fonts/Arial-Bold-12.pcf")
LINE_SPACING = 0.8
HEIGHT = arial.get_bounding_box()[1]
QUOTE_X = 10
QUOTE_Y = 7

Now, the display background and text labels are set up and added to the display group.

rect = Rect(0, 0, 296, 128, fill=0xFFFFFF, outline=0xFFFFFF)
splash.append(rect)

quote = label.Label(
    font=arial,
    x=QUOTE_X,
    y=QUOTE_Y,
    color=0x000000,
    line_spacing=LINE_SPACING,
)

splash.append(quote)
time_label = label.Label(
    font=bold,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(time_label)

time_label_2 = label.Label(
    font=bold,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(time_label_2)

after_label = label.Label(
    font=arial,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(after_label)

after_label_2 = label.Label(
    font=arial,
    color=0x000000,
    line_spacing=LINE_SPACING,
)
splash.append(after_label_2)

author_label = label.Label(
    font=arial, x=QUOTE_X, y=115, color=0x000000, line_spacing=LINE_SPACING
)
splash.append(author_label)

After that, the MagTag attempts to connect to the internet.

try:
    from secrets import secrets
except ImportError:
    print("WiFi secrets are kept in secrets.py, please add them there!")
    raise

aio_username = secrets["aio_username"]
aio_key = secrets["aio_key"]

print(f"Connecting to {secrets['ssid']}")
wifi.radio.connect(secrets["ssid"], secrets["password"])
print(f"Connected to {secrets['ssid']}!")

At this point, we start defining a few helper functions.

The first one, get_width, is used to get the width of a string, in pixels, when passed the string and the font the string will be displayed in.

The next one, smart_split, is used to tell the code when to wrap a line when it's not the first label being used in a block of text. This is necessary since the code uses multiple fonts (bold and normal Arial 12pt.) in the same text block.

The last two are functions that are run when Adafruit IO is initially connected to - it subscribes the user to the ISO formatted time feed - and when it is disconnected from, respectively.

def get_width(font, text):
    return sum(font.get_glyph(ord(c)).shift_x for c in text)


def smart_split(text, font, width):
    words = ""
    spl = text.split(" ")
    for i, word in enumerate(spl):
        words += f" {word}"
        lwidth = get_width(font, words)
        if width + lwidth > 276:
            spl[i] = "\n" + spl[i]
            text = " ".join(spl)
            break
    return text


def connected(client):  # pylint: disable=unused-argument
    io.subscribe_to_time("iso")


def disconnected(client):  # pylint: disable=unused-argument
    print("Disconnected from Adafruit IO!")

This function is run whenever the quote to be displayed is updated. It's a bit complicated but a very important part of this project.

It starts by wiping all of the labels since we don't use every single label every time.

It then goes on to separate the different parts of the quote so it can set one part of that as bold and the rest as normal and sets the text of the part of the quote prior to the time.

Then the code for setting the location of the time text and the text after the time text is run, which account for the possibility that the first line of that may need to be wrapped over to the next line.

Finally, the display is refreshed with the new quote.

def update_text(hour_min):
    quote.text = (
        time_label.text
    ) = time_label_2.text = after_label.text = after_label_2.text = ""

    before, time_text, after = quotes[hour_min][0].split("^")
    text = adafruit_display_text.wrap_text_to_pixels(before, 276, font=arial)
    quote.text = "\n".join(text)

    for line in text:
        width = get_width(arial, line)

    time_text = smart_split(time_text, bold, width)

    split_time = time_text.split("\n")
    if time_text[0] != "\n":
        time_label.x = time_x = QUOTE_X + width
        time_label.y = time_y = QUOTE_Y + int((len(text) - 1) * HEIGHT * LINE_SPACING)
        time_label.text = split_time[0]
    if "\n" in time_text:
        time_label_2.x = time_x = QUOTE_X
        time_label_2.y = time_y = QUOTE_Y + int(len(text) * HEIGHT * LINE_SPACING)
        wrapped = adafruit_display_text.wrap_text_to_pixels(
            split_time[1], 276, font=arial
        )
        time_label_2.text = "\n".join(wrapped)
    width = get_width(bold, split_time[-1]) + time_x - QUOTE_X

    if after:
        after = smart_split(after, arial, width)

        split_after = after.split("\n")
        if after[0] != "\n":
            after_label.x = QUOTE_X + width
            after_label.y = time_y
            after_label.text = split_after[0]
        if "\n" in after:
            after_label_2.x = QUOTE_X
            after_label_2.y = time_y + int(HEIGHT * LINE_SPACING)
            wrapped = adafruit_display_text.wrap_text_to_pixels(
                split_after[1], 276, font=arial
            )
            after_label_2.text = "\n".join(wrapped)

    author = f"{quotes[hour_min][2]} - {quotes[hour_min][1]}"
    author_label.text = adafruit_display_text.wrap_text_to_pixels(
        author, 276, font=arial
    )[0]
    time.sleep(display.time_to_refresh + 0.1)
    display.refresh()

This function is run whenever the IO feed gets a new value, so roughly once a second. It starts by converting the received UTC time into the local time.

Then it checks to see if the time received is the same hour and minute as the last time received and if a quote entry exists for said time. If it isn't the same time and a quote does exist, the code then sends the time to the function above to update the quote.

LAST = None


def message(client, feed_id, payload):  # pylint: disable=unused-argument
    global LAST  # pylint: disable=global-statement
    timezone = adafruit_datetime.timezone.utc
    timezone._offset = adafruit_datetime.timedelta(  # pylint: disable=protected-access
        seconds=UTC_OFFSET * 3600
    )
    datetime = adafruit_datetime.datetime.fromisoformat(payload[:-1]).replace(
        tzinfo=timezone
    )
    local_datetime = datetime.tzinfo.fromutc(datetime)
    print(local_datetime)
    hour_min = f"{local_datetime.hour:02}:{local_datetime.minute:02}"
    if local_datetime.minute != LAST:
        if hour_min in quotes:
            update_text(hour_min)

    LAST = local_datetime.minute
    gc.collect()

However, before any of those functions can be used, the code needs to set up the Adafruit IO MQTT connection, which the following code does.

# Create a socket pool
pool = socketpool.SocketPool(wifi.radio)

# Initialize a new MQTT Client object
mqtt_client = MQTT.MQTT(
    broker="io.adafruit.com",
    port=1883,
    username=secrets["aio_username"],
    password=secrets["aio_key"],
    socket_pool=pool,
    ssl_context=ssl.create_default_context(),
)

# Initialize an Adafruit IO MQTT Client
io = IO_MQTT(mqtt_client)

# Connect the callback methods defined above to Adafruit IO
io.on_connect = connected
io.on_disconnect = disconnected
io.on_message = message

# Connect to Adafruit IO
print("Connecting to Adafruit IO...")
io.connect()

After it is connected the code runs through this loop to continually check for a new feed update from the Adafruit IO time feed.

while True:
    try:
        io.loop()
    except (ValueError, RuntimeError) as e:
        print("Failed to get data, retrying\n", e)
        wifi.reset()
        io.reconnect()
        continue
    time.sleep(1)

This guide was first published on Nov 08, 2022. It was last updated on May 26, 2024.

This page (Code the MagTag Quote Clock) was last updated on May 25, 2024.

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