Overview
If you're like me, one of the things that makes cooking kind of difficult is keeping track of time. This project makes that much less of an issue, giving you a magnetic timer that you can put just about anywhere with both visual and sound alerts to tell you when the timer is done.
This project uses the eInk display, NeoPixels, and built-in buttons of the Adafruit MagTag to make a rechargeable, programmable kitchen timer that is also magnetic. The MagTag displays the time left and then plays an alarm through the speaker and flashes the NeoPixels when the timer is done.
This kit contains all the parts except for a cable:
Or get the pieces separately:
Get a USB-A to USB-C cable to connect your computer to the MagTag:
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Install CircuitPython
CircuitPython is a derivative of MicroPython designed to simplify experimentation and education on low-cost microcontrollers. It makes it easier than ever to get prototyping by requiring no upfront desktop software downloads. Simply copy and edit files on the CIRCUITPY drive to iterate.
Click the link above and download the latest .BIN and .UF2 file
You can use a 9.x.x release for a pre-2025 MagTag. You must use a 10.x.x release for the updated MagTag 2025 Edition.
(depending on how you program the ESP32S2 board you may need one or the other, might as well get both)
Download and save it to your desktop (or wherever is handy).
Plug your MagTag into your computer using a known-good USB cable.
A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync.
Option 1 - Load with UF2 Bootloader
This is by far the easiest way to load CircuitPython. However it requires your board has the UF2 bootloader installed. Some early boards do not (we hadn't written UF2 yet!) - in which case you can load using the built in ROM bootloader.
Still, try this first!
Try Launching UF2 Bootloader
Loading CircuitPython by drag-n-drop UF2 bootloader is the easier way and we recommend it. If you have a MagTag where the front of the board is black, your MagTag came with UF2 already on it.
Launch UF2 by double-clicking the Reset button (the one next to the USB C port). You may have to try a few times to get the timing right.
If you're using Windows and you get an error at the end of the file copy that says Error from the file copy, Error 0x800701B1: A device which does not exist was specified. You can ignore this error, the bootloader sometimes disconnects without telling Windows, the install completed just fine and you can continue. If its really annoying, you can also upgrade the bootloader (the latest version of the UF2 bootloader fixes this warning)
Your board should auto-reset into CircuitPython, or you may need to press reset. A CIRCUITPY drive will appear. You're done! Go to the next pages.
Option 2 - Use esptool to load BIN file
If you have an original MagTag with while soldermask on the front, we didn't have UF2 written for the ESP32S2 yet so it will not come with the UF2 bootloader.
You can upload with esptool to the ROM (hardware) bootloader instead!
Follow the initial steps found in the Run esptool and check connection section of the ROM Bootloader page to verify your environment is set up, your board is successfully connected, and which port it's using.
In the final command to write a binary file to the board, replace the port with your port, and replace "firmware.bin" with the the file you downloaded above.
The output should look something like the output in the image.
Press reset to exit the bootloader.
Your CIRCUITPY drive should appear!
You're all set! Go to the next pages.
Option 3 - Use Chrome Browser To Upload BIN file
If for some reason you cannot get esptool to run, you can always try using the Chrome-browser version of esptool we have written. This is handy if you don't have Python on your computer, or something is really weird with your setup that makes esptool not run (which happens sometimes and isn't worth debugging!) You can follow along on the Web Serial ESPTool page and either load the UF2 bootloader and then come back to Option 1 on this page, or you can download the CircuitPython BIN file directly using the tool in the same manner as the bootloader.
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CircuitPython Internet Test
One of the great things about most Espressif microcontrollers are their built-in WiFi capabilities. This page covers the basics of getting connected using CircuitPython.
The first thing you need to do is update your code.py to the following (it will error until WiFi details are added). Click the Download Project Bundle button to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, and copy the entire lib folder and the code.py file to your CIRCUITPY drive.
# SPDX-FileCopyrightText: 2020 Brent Rubell for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import os
import ipaddress
import ssl
import wifi
import socketpool
import adafruit_requests
# URLs to fetch from
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_QUOTES_URL = "https://www.adafruit.com/api/quotes.php"
JSON_STARS_URL = "https://api.github.com/repos/adafruit/circuitpython"
print("ESP32-S2 WebClient Test")
print(f"My MAC address: {[hex(i) for i in wifi.radio.mac_address]}")
print("Available WiFi networks:")
for network in wifi.radio.start_scanning_networks():
print("\t%s\t\tRSSI: %d\tChannel: %d" % (str(network.ssid, "utf-8"),
network.rssi, network.channel))
wifi.radio.stop_scanning_networks()
print(f"Connecting to {os.getenv('CIRCUITPY_WIFI_SSID')}")
wifi.radio.connect(os.getenv("CIRCUITPY_WIFI_SSID"), os.getenv("CIRCUITPY_WIFI_PASSWORD"))
print(f"Connected to {os.getenv('CIRCUITPY_WIFI_SSID')}")
print(f"My IP address: {wifi.radio.ipv4_address}")
ping_ip = ipaddress.IPv4Address("8.8.8.8")
ping = wifi.radio.ping(ip=ping_ip)
# retry once if timed out
if ping is None:
ping = wifi.radio.ping(ip=ping_ip)
if ping is None:
print("Couldn't ping 'google.com' successfully")
else:
# convert s to ms
print(f"Pinging 'google.com' took: {ping * 1000} ms")
pool = socketpool.SocketPool(wifi.radio)
requests = adafruit_requests.Session(pool, ssl.create_default_context())
print(f"Fetching text from {TEXT_URL}")
response = requests.get(TEXT_URL)
print("-" * 40)
print(response.text)
print("-" * 40)
print(f"Fetching json from {JSON_QUOTES_URL}")
response = requests.get(JSON_QUOTES_URL)
print("-" * 40)
print(response.json())
print("-" * 40)
print()
print(f"Fetching and parsing json from {JSON_STARS_URL}")
response = requests.get(JSON_STARS_URL)
print("-" * 40)
print(f"CircuitPython GitHub Stars: {response.json()['stargazers_count']}")
print("-" * 40)
print("Done")
Your CIRCUITPY drive should resemble the following.
To get connected, the next thing you need to do is update the settings.toml file.
The settings.toml File
We expect people to share tons of projects as they build CircuitPython WiFi widgets. What we want to avoid is people accidentally sharing their passwords or secret tokens and API keys. So, we designed all our examples to use a settings.toml file, that is on your CIRCUITPY drive, to hold secret/private/custom data. That way you can share your main project without worrying about accidentally sharing private stuff.
If you have a fresh install of CircuitPython on your board, the initial settings.toml file on your CIRCUITPY drive is empty.
To get started, you can update the settings.toml on your CIRCUITPY drive to contain the following code.
# SPDX-FileCopyrightText: 2023 Adafruit Industries # # SPDX-License-Identifier: MIT # This is where you store the credentials necessary for your code. # The associated demo only requires WiFi, but you can include any # credentials here, such as Adafruit IO username and key, etc. CIRCUITPY_WIFI_SSID = "your-wifi-ssid" CIRCUITPY_WIFI_PASSWORD = "your-wifi-password"
This file should contain a series of Python variables, each assigned to a string. Each variable should describe what it represents (say wifi_ssid), followed by an = (equals sign), followed by the data in the form of a Python string (such as "my-wifi-password" including the quote marks).
At a minimum you'll need to add/update your WiFi SSID and WiFi password, so do that now!
As you make projects you may need more tokens and keys, just add them one line at a time. See for example other tokens such as one for accessing GitHub or the Hackaday API. Other non-secret data like your timezone can also go here.
For the correct time zone string, look at http://worldtimeapi.org/timezones and remember that if your city is not listed, look for a city in the same time zone, for example Boston, New York, Philadelphia, Washington DC, and Miami are all on the same time as New York.
Of course, don't share your settings.toml - keep that out of GitHub, Discord or other project-sharing sites.
If you connect to the serial console, you should see something like the following:
In order, the example code...
Checks the ESP32's MAC address.
print(f"My MAC address: {[hex(i) for i in wifi.radio.mac_address]}")
Performs a scan of all access points and prints out the access point's name (SSID), signal strength (RSSI), and channel.
print("Available WiFi networks:")
for network in wifi.radio.start_scanning_networks():
print("\t%s\t\tRSSI: %d\tChannel: %d" % (str(network.ssid, "utf-8"),
network.rssi, network.channel))
wifi.radio.stop_scanning_networks()
Connects to the access point you defined in the settings.toml file, and prints out its local IP address.
print(f"Connecting to {os.getenv('WIFI_SSID')}")
wifi.radio.connect(os.getenv("WIFI_SSID"), os.getenv("WIFI_PASSWORD"))
print(f"Connected to {os.getenv('WIFI_SSID')}")
print(f"My IP address: {wifi.radio.ipv4_address}")
Attempts to ping a Google DNS server to test connectivity. If a ping fails, it returns None. Initial pings can sometimes fail for various reasons. So, if the initial ping is successful (is not None), it will print the echo speed in ms. If the initial ping fails, it will try one more time to ping, and then print the returned value. If the second ping fails, it will result in "Ping google.com: None ms" being printed to the serial console. Failure to ping does not always indicate a lack of connectivity, so the code will continue to run.
ping_ip = ipaddress.IPv4Address("8.8.8.8")
ping = wifi.radio.ping(ip=ping_ip) * 1000
if ping is not None:
print(f"Ping google.com: {ping} ms")
else:
ping = wifi.radio.ping(ip=ping_ip)
print(f"Ping google.com: {ping} ms")
The code creates a socketpool using the wifi radio's available sockets. This is performed so we don't need to re-use sockets. Then, it initializes a a new instance of the requests interface - which makes getting data from the internet really really easy.
pool = socketpool.SocketPool(wifi.radio) requests = adafruit_requests.Session(pool, ssl.create_default_context())
To read in plain-text from a web URL, call requests.get - you may pass in either a http, or a https url for SSL connectivity.
print(f"Fetching text from {TEXT_URL}")
response = requests.get(TEXT_URL)
print("-" * 40)
print(response.text)
print("-" * 40)
Requests can also display a JSON-formatted response from a web URL using a call to requests.get.
print(f"Fetching json from {JSON_QUOTES_URL}")
response = requests.get(JSON_QUOTES_URL)
print("-" * 40)
print(response.json())
print("-" * 40)
Finally, you can fetch and parse a JSON URL using requests.get. This code snippet obtains the stargazers_count field from a call to the GitHub API.
print(f"Fetching and parsing json from {JSON_STARS_URL}")
response = requests.get(JSON_STARS_URL)
print("-" * 40)
print(f"CircuitPython GitHub Stars: {response.json()['stargazers_count']}")
print("-" * 40)
OK you now have your ESP32 board set up with a proper settings.toml file and can connect over the Internet. If not, check that your settings.toml file has the right SSID and password and retrace your steps until you get the Internet connectivity working!
IPv6 Networking
Starting in CircuitPython 9.2, IPv6 networking is available on most Espressif wifi boards. Socket-using libraries like adafruit_requests and adafruit_ntp will need to be updated to use the new APIs and for now can only connect to services on IPv4.
IPv6 connectivity & privacy
IPv6 addresses are divided into many special kinds, and many of those kinds (like those starting with FC, FD, FE) are private or local; Addresses starting with other prefixes like 2002: and 2001: are globally routable. In 2024, far from all ISPs and home networks support IPv6 internet connectivity. For more info consult resources like Wikipedia. If you're interested in global IPv6 connectivity you can use services like Hurricane Electric to create an "IPv6 tunnel" (free as of 2024, but requires expertise and a compatible router or host computer to set up)
It's also important to be aware that, as currently implemented by Espressif, there are privacy concerns especially when these devices operate on the global IPv6 network: The device's unique identifier (its EUI-64 or MAC address) is used by default as part of its IPv6 address. This means that the device identity can be tracked across multiple networks by any service it connects to.
Enable IPv6 networking
Due to the privacy consideration, IPv6 networking is not automatically enabled. Instead, it must be explicitly enabled by a call to start_dhcp_client with the ipv6=True argument specified:
wifi.start_dhcp_client(ipv6=True)
Check IP addresses
The read-only addresses property of the wifi.radio object holds all addresses, including IPv4 and IPv6 addresses:
>>> wifi.radio.addresses
('FE80::7EDF:A1FF:FE00:518C', 'FD5F:3F5C:FE50:0:7EDF:A1FF:FE00:518C', '10.0.3.96')
The wifi.radio.dns servers can be IPv4 or IPv6:
>>> wifi.radio.dns
('FD5F:3F5C:FE50::1',)
>>> wifi.radio.dns = ("1.1.1.1",)
>>> wifi.radio.dns
('1.1.1.1',)
>>> wifi.radio.ping("google.com")
0.043
>>> wifi.radio.ping("ipv6.google.com")
0.048
Create & use IPv6 sockets
Use the address family socket.AF_INET6. After the socket is created, use methods like connect, send, recfrom_into, etc just like for IPv4 sockets. This code snippet shows communicating with a private-network NTP server; this IPv6 address will not work on your network:
>>> ntp_addr = ("fd5f:3f5c:fe50::20e", 123)
>>> PACKET_SIZE = 48
>>>
>>> buf = bytearray(PACKET_SIZE)
>>> with socket.socket(socket.AF_INET6, socket.SOCK_DGRAM) as s:
... s.settimeout(1)
... buf[0] = 0b0010_0011
... s.sendto(buf, ntp_addr)
... print(s.recvfrom_into(buf))
... print(buf)
...
48
(48, ('fd5f:3f5c:fe50::20e', 123))
bytearray(b'$\x01\x03\xeb\x00\x00\x00\x00\x00\x00\x00GGPS\x00\xeaA0h\x07s;\xc0\x00\x00\x00\x00\x00\x00\x00\x00\xeaA0n\xeb4\x82-\xeaA0n\xebAU\xb1')
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Getting The Date & Time
A very common need for projects is to know the current date and time. Especially when you want to deep sleep until an event, or you want to change your display based on what day, time, date, etc. it is
Determining the correct local time is really really hard. There are various time zones, Daylight Savings dates, leap seconds, etc. Trying to get NTP time and then back-calculating what the local time is, is extraordinarily hard on a microcontroller just isn't worth the effort and it will get out of sync as laws change anyways.
For that reason, we have the free adafruit.io time service. Free for anyone with a free adafruit.io account. You do need an account because we have to keep accidentally mis-programmed-board from overwhelming adafruit.io and lock them out temporarily. Again, it's free!
Step 1) Make an Adafruit account
It's free! Visit https://accounts.adafruit.com/ to register and make an account if you do not already have one
Step 2) Sign into Adafruit IO
Head over to io.adafruit.com and click Sign In to log into IO using your Adafruit account. It's free and fast to join.
You will get a popup with your Username and Key (In this screenshot, we've covered it with red blocks)
Go to the settings.toml file on your CIRCUITPY drive (or create one with the text editor with your operating system) and add three lines for AIO_USERNAME, ADAFRUIT_AIO_KEY and TIMEZONE so you get something like the following:
# This file is where you keep secret settings, passwords, and tokens! # If you put them in the code you risk committing that info or sharing it CIRCUITPY_WIFI_SSID = "your-wifi-ssid" CIRCUITPY_WIFI_PASSWORD = "your-wifi-password" ADAFRUIT_AIO_USERNAME = "your-adafruit-io-username" ADAFRUIT_AIO_KEY = "your-adafruit-io-key" # Timezone names from http://worldtimeapi.org/timezones TIMEZONE="America/New_York"
The timezone is optional, if you don't have that entry, adafruit.io will guess your timezone based on geographic IP address lookup. You can visit http://worldtimeapi.org/timezones to see all the time zones available (even though we do not use Worldtime for time-keeping, we do use the same time zone table).
Step 4) Upload Test Python Code
This code is like the Internet Test code from before, but this time it will connect to adafruit.io and get the local time
import ipaddress
import os
import ssl
import wifi
import socketpool
import adafruit_requests
# Get our username, key and desired timezone
ssid = os.getenv("CIRCUITPY_WIFI_SSID")
password = os.getenv("CIRCUITPY_WIFI_PASSWORD")
aio_username = os.getenv("ADAFRUIT_AIO_USERNAME")
aio_key = os.getenv("ADAFRUIT_AIO_KEY")
timezone = os.getenv("TIMEZONE")
TIME_URL = f"https://io.adafruit.com/api/v2/{aio_username}/integrations/time/strftime?x-aio-key={aio_key}&tz={timezone}"
TIME_URL += "&fmt=%25Y-%25m-%25d+%25H%3A%25M%3A%25S.%25L+%25j+%25u+%25z+%25Z"
print("ESP32-S2 Adafruit IO Time test")
print("My MAC addr:", [hex(i) for i in wifi.radio.mac_address])
print("Available WiFi networks:")
for network in wifi.radio.start_scanning_networks():
print("\t%s\t\tRSSI: %d\tChannel: %d" % (str(network.ssid, "utf-8"),
network.rssi, network.channel))
wifi.radio.stop_scanning_networks()
print("Connecting to", ssid)
wifi.radio.connect(ssid, password)
print(f"Connected to {ssid}!")
print("My IP address is", wifi.radio.ipv4_address)
ipv4 = ipaddress.ip_address("8.8.4.4")
print("Ping google.com:", wifi.radio.ping(ipv4), "ms")
pool = socketpool.SocketPool(wifi.radio)
requests = adafruit_requests.Session(pool, ssl.create_default_context())
print("Fetching text from", TIME_URL)
response = requests.get(TIME_URL)
print("-" * 40)
print(response.text)
print("-" * 40)
After running this, you will see something like the below text. We have blocked out the part with the secret username and key data!
Note at the end you will get the date, time, and your timezone! If so, you have correctly configured your settings.toml and can continue to the next steps!
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Code the Kitchen Timer
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 MagTag_Kitchen_Timer/ 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.
Your CIRCUITPY drive should now look similar to the following image:
# SPDX-FileCopyrightText: 2020 Eva Herrada for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import time
import terminalio
from adafruit_magtag.magtag import MagTag
magtag = MagTag()
magtag.peripherals.neopixel_disable = False
magtag.add_text(
text_font=terminalio.FONT,
text_position=(140, 55),
text_scale=7,
text_anchor_point=(0.5, 0.5),
)
magtag.set_text("00:00")
# Function that makes the neopixels display the seconds left
def update_neopixels(seconds):
n = seconds // 15
for j in range(n):
magtag.peripherals.neopixels[3 - j] = (128, 0, 0)
magtag.peripherals.neopixels[3 - n] = (int(((seconds / 15) % 1) * 128), 0, 0)
alarm_set = False
while True:
if not alarm_set:
# Set the timer to 1 minute
if magtag.peripherals.button_a_pressed:
alarm_time = 60
alarm_set = True
start = time.time()
magtag.set_text("01:00")
last_set = 60
magtag.peripherals.neopixels.fill((128, 0, 0))
# Set the timer to 5 minutes
elif magtag.peripherals.button_b_pressed:
alarm_time = 300
alarm_set = True
start = time.time()
magtag.set_text("05:00")
last_set = 300
magtag.peripherals.neopixels.fill((128, 0, 0))
# Set the timer to 20 minutes
elif magtag.peripherals.button_c_pressed:
alarm_time = 1200
alarm_set = True
start = time.time()
magtag.set_text("20:00")
last_set = 1200
magtag.peripherals.neopixels.fill((128, 0, 0))
else:
time.sleep(1)
remaining = alarm_time - (time.time() - start)
if (remaining < 0):
remaining = 0
print(remaining)
if remaining == 0:
magtag.peripherals.neopixels.fill((255, 0, 0))
# Play alarm and flash neopixels to indicate the timer is done
for i in range(2):
magtag.peripherals.neopixels.fill((255, 0, 0))
magtag.peripherals.play_tone(3000, 0.5)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.1)
magtag.peripherals.neopixels.fill((255, 0, 0))
magtag.peripherals.play_tone(3000, 0.5)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.5)
alarm_set = False
magtag.set_text("00:00")
last_set = 0
continue
update_neopixels(remaining % 60)
if remaining % 60 == 0 and remaining != last_set:
magtag.set_text("{:02d}:00".format(remaining // 60))
last_set = remaining
# Reset the timer
if magtag.peripherals.button_d_pressed:
time.sleep(0.1)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.1)
magtag.peripherals.neopixels.fill((255, 0, 0))
time.sleep(0.1)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.1)
alarm_set = False
magtag.set_text("00:00")
Code Behavior
I'll quickly explain how to use this because I recognize it may not be too obvious at first. To set an alarm, press one of the first three buttons. The first button sets a 1-minute alarm, the second one sets a 5-minute alarm, and the third one sets a 20-minute alarm, but you can change these values by making a few small edits in the code that I'll explain in the 'Code Run Through' section. The fourth button stops the current alarm, allowing the user to set a new one.
When the code is running, the number of minutes left will be displayed on the display. However, this only updates once a minute so the built-in NeoPixels are also used as indicators for the seconds. Each NeoPixel represents 15 seconds, so if there are 3 NeoPixels lit and the display says "05:00", there is between 5:30 and 5:45 left on the timer. The NeoPixel furthest to the right that is still illuminated will slowly dim so that at the end of the 15 seconds that it is indicating it will turn off.
import time import terminalio from adafruit_magtag.magtag import MagTag
Then, the code initializes the MagTag object and makes sure built-in NeoPixels are enabled.
magtag = MagTag() magtag.peripherals.neopixel_disable = False
After that, the text object is added to the center of the display and it is set to "00:00."
magtag.add_text(
text_font=terminalio.FONT,
text_position=(140, 55),
text_scale=7,
text_anchor_point=(0.5, 0.5),
)
magtag.set_text("00:00")
Now, the code defines a function, update_neopixels. This function takes the amount of seconds left in the current minute (so if there were 5 minutes and 33 seconds left in the timer, the function would be given 33) and dims one NeoPixel at a time. At 59 seconds, all 4 NeoPixels are fully illuminated. At 46 seconds, the NeoPixel furthest to the right is almost completely out but the other three are still fully illuminated, and when this function is given 45 seconds, it will turn the fourth NeoPixel off and start dimming the third one.
def update_neopixels(seconds):
n = seconds // 15
for j in range(n):
magtag.peripherals.neopixels[3 - j] = (128, 0, 0)
magtag.peripherals.neopixels[3 - n] = (int(((seconds / 15) % 1) * 128), 0, 0)
At this point, the main loop starts. It first checks to see if an alarm is currently active. If there isn't an active alarm, it starts scanning to see if a button is pressed. If button a, b, or c (first three buttons, going left to right) is pressed, it then activates an alarm and sets a few variables that make keeping track of the alarm easier.
If you want to change the time an alarm lasts, change alarm_time, the string in magtag.set_text, and last_set.
alarm_set = False
while True:
if not alarm_set:
# Set the timer to 1 minute
if magtag.peripherals.button_a_pressed:
alarm_time = 60
alarm_set = True
start = time.time()
magtag.set_text("01:00")
last_set = 60
magtag.peripherals.neopixels.fill((128, 0, 0))
# Set the timer to 5 minutes
elif magtag.peripherals.button_b_pressed:
alarm_time = 300
alarm_set = True
start = time.time()
magtag.set_text("05:00")
last_set = 300
magtag.peripherals.neopixels.fill((128, 0, 0))
# Set the timer to 20 minutes
elif magtag.peripherals.button_c_pressed:
alarm_time = 1200
alarm_set = True
start = time.time()
magtag.set_text("20:00")
last_set = 1200
magtag.peripherals.neopixels.fill((128, 0, 0))
This next part of the loop only gets executed when alarm_set is True, that is to say when an alarm is active. It starts by printing out the time left in the alarm (in seconds) to the serial console. Then, if the time remaining has reached zero, it plays an alarm through the speaker and flashes the NeoPixels on and off a few times to indicate that the alarm is done. Next, it sets the necessary variables to indicate that an alarm isn't set.
else:
time.sleep(1)
remaining = alarm_time - (time.time() - start)
if (remaining < 0):
remaining = 0
print(remaining)
if remaining == 0:
magtag.peripherals.neopixels.fill((255, 0, 0))
# Play alarm and flash neopixels to indicate the timer is done
for i in range(2):
magtag.peripherals.neopixels.fill((255, 0, 0))
magtag.peripherals.play_tone(3000, 0.5)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.1)
magtag.peripherals.neopixels.fill((255, 0, 0))
magtag.peripherals.play_tone(3000, 0.5)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.5)
alarm_set = False
magtag.set_text("00:00")
last_set = 0
continue
If there is still time left in the alarm, update_neopixels is called. The code then checks to see if there is a whole number of minutes left and if there is, updates the display to reflect that.
update_neopixels(remaining % 60)
if remaining % 60 == 0 and remaining != last_set:
magtag.set_text("{:02d}:00".format(remaining // 60))
last_set = remaining
Finally, the code checks to see if button D (furthest to the right) is being pressed. If it is, it flashes the NeoPixels a few times and resets the alarm.
# Reset the timer
if magtag.peripherals.button_d_pressed:
time.sleep(0.1)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.1)
magtag.peripherals.neopixels.fill((255, 0, 0))
time.sleep(0.1)
magtag.peripherals.neopixels.fill((0, 0, 0))
time.sleep(0.1)
alarm_set = False
magtag.set_text("00:00")
Page last edited March 08, 2024
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