Stay up to date with your favorite Twitter feed with this MagTag Twitter display.

This guide will show you how to use an Adafruit MagTag, CircuitPython and the Twitter API to fetch and display the latest tweets from a Twitter account. After the MagTag fetches a tweet, it goes into deep-sleep mode for 15 minutes to conserve power.

Parts

The starter kit includes everything you need to use the Adafruit MagTag.

The Adafruit MagTag combines the new ESP32-S2 wireless module and a 2.9" grayscale E-Ink display to make a low-power IoT display that can show data on its screen...
$44.95
In Stock

Or, you can purchase the parts for this project individually.

The Adafruit MagTag combines the new ESP32-S2 wireless module and a 2.9" grayscale E-Ink display to make a low-power IoT display that can show data on its screen even when power...
$34.95
In Stock
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This...
$6.95
In Stock
Got a glorious RGB Matrix project you want to mount and display in your workspace or home? If you have one of the matrix panels listed below, you'll need a pack of these...
$2.50
In Stock

There are optional frames if you like:

Here is the perfect kit with two faceplate options for your MagTag, including a vivid Red Arrow plate and a dreamy white Cloud plate. And of course, the mounting hardware is included,...
$5.95
In Stock

You'll also want to pick up a USB Type C cable to connect the MagTag to your computer.

As technology changes and adapts, so does Adafruit. This  USB Type A to Type C cable will help you with the transition to USB C, even if you're still...
$3.95
In Stock
As technology changes and adapts, so does Adafruit. This  USB Type A to Type C cable will help you with the transition to USB C, even if you're still...
$4.95
In Stock

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.

Set Up CircuitPython

Follow the steps to get CircuitPython installed on your MagTag.

Click the link above and download the latest .BIN and .UF2 file

(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 the UF2 bootloader is installed, you will see a new disk drive appear called MAGTAGBOOT

Copy the UF2 file you downloaded at the first step of this tutorial onto the MAGTAGBOOT drive

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.

To use the internet-connectivity built into your ESP32-S2 with CircuitPython, you must first install a number of libraries. This page covers that process.

Adafruit CircuitPython Library Bundle

Download the Adafruit CircuitPython Bundle. You can find the latest release here:

Download the adafruit-circuitpython-bundle-version-mpy-*.zip bundle zip file, and unzip a folder of the same name. Inside you'll find a lib folder. The entire collection of libraries is too large to fit on the CIRCUITPY drive. Instead, add each library as you need it, this will reduce the space usage but you'll need to put in a little more effort.

At a minimum we recommend the following libraries, in fact we more than recommend. They're basically required. So grab them and install them into CIRCUITPY/lib now!

  • adafruit_requests.mpy - A requests-like library for HTTP commands.
  • neopixel.mpy - Helper library to use NeoPixel LEDs, often built into the boards so they're great for quick feedback

Once you have added those files, please continue to the next page to set up and test Internet connectivity

Once you have CircuitPython installed and the minimum libraries installed we can get your board connected to the Internet. 

To get connected, you will need to start by creating a secrets.py file.

Secrets 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 secrets.py file, that is in your CIRCUITPY drive, to hold secret/private/custom data. That way you can share your main project without worrying about accidentally sharing private stuff.

Your secrets.py file should look like this:

# 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

secrets = {
    'ssid' : 'home_wifi_network',
    'password' : 'wifi_password',
    'aio_username' : 'my_adafruit_io_username',
    'aio_key' : 'my_adafruit_io_key',
    'timezone' : "America/New_York", # http://worldtimeapi.org/timezones
    }

Copy and paste that text/code into a file called secrets.py and save it to your CIRCUITPY folder like so:

Inside is a python dictionary named secrets with a line for each entry. Each entry has an entry name (say 'ssid') and then a colon to separate it from the entry key 'home ssid' and finally a comma ,

At a minimum you'll need to adjust the ssid and password for your local WiFi setup 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, just cause its called secrets doesn't mean you can't have general customization data in there!

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 secrets.py - keep that out of GitHub, Discord or other project-sharing sites.

Don't share your secrets.py file, it has your passwords and API keys in it!

Connect to WiFi

OK now you have your secrets setup - you can connect to the Internet using the Requests module.

First make sure you are running the latest version of Adafruit CircuitPython for your board.

Next you'll need to install the necessary libraries to use the hardware--carefully follow the steps to find and install these libraries from Adafruit's CircuitPython library bundle. Our introduction guide has a great page on how to install the library bundle.

  • adafruit_requests
  • neopixel

Before continuing make sure your board's CIRCUITPY/lib folder or root filesystem has the above files copied over.

Once that's done, load up the following example using Mu or your favorite editor:

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"

# Get wifi details and more from a secrets.py file
try:
    from secrets import secrets
except ImportError:
    print("WiFi secrets are kept in secrets.py, please add them there!")
    raise

print("ESP32-S2 WebClient 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 %s"%secrets["ssid"])
wifi.radio.connect(secrets["ssid"], secrets["password"])
print("Connected to %s!"%secrets["ssid"])
print("My IP address is", wifi.radio.ipv4_address)

ipv4 = ipaddress.ip_address("8.8.4.4")
print("Ping google.com: %f ms" % (wifi.radio.ping(ipv4)*1000))

pool = socketpool.SocketPool(wifi.radio)
requests = adafruit_requests.Session(pool, ssl.create_default_context())

print("Fetching text from", TEXT_URL)
response = requests.get(TEXT_URL)
print("-" * 40)
print(response.text)
print("-" * 40)

print("Fetching json from", JSON_QUOTES_URL)
response = requests.get(JSON_QUOTES_URL)
print("-" * 40)
print(response.json())
print("-" * 40)

print()

print("Fetching and parsing json from", JSON_STARS_URL)
response = requests.get(JSON_STARS_URL)
print("-" * 40)
print("CircuitPython GitHub Stars", response.json()["stargazers_count"])
print("-" * 40)

print("done")

And save it to your board. Make sure the file is named code.py.

Open up your REPL, you should see something like the following:

In order, the example code...

Checks the ESP32-S2's MAC address.

print("My MAC addr:", [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("Avaliable 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 secrets.py file, prints out its local IP address, and attempts to ping google.com to check its network connectivity. 

print("Connecting to %s"%secrets["ssid"])
wifi.radio.connect(secrets["ssid"], secrets["password"])
print(print("Connected to %s!"%secrets["ssid"]))
print("My IP address is", wifi.radio.ipv4_address)

ipv4 = ipaddress.ip_address("8.8.4.4")
print("Ping google.com: %f ms" % wifi.radio.ping(ipv4))

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("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("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("Fetching and parsing json from", JSON_STARS_URL)
response = requests.get(JSON_STARS_URL)
print("-" * 40)
print("CircuitPython GitHub Stars", response.json()["stargazers_count"])
print("-" * 40)

OK you now have your ESP32-S2 board set up with a proper secrets.py file and can connect over the Internet. If not, check that your secrets.py file has the right ssid and password and retrace your steps until you get the Internet connectivity working!

To use all the amazing features of your MagTag with CircuitPython, you must first install a number of libraries. This page covers that process.

Get Latest Adafruit CircuitPython Bundle

Download the Adafruit CircuitPython Library Bundle. You can find the latest release here:

Download the adafruit-circuitpython-bundle-version-mpy-*.zip bundle zip file, and unzip a folder of the same name. Inside you'll find a lib folder. The entire collection of libraries is too large to fit on the CIRCUITPY drive. Therefore, you'll need to copy the necessary libraries to your board individually.

At a minimum, the following libraries are required. Copy the following folders or .mpy files to the lib folder on your CIRCUITPY drive. If the library is a folder, copy the entire folder to the lib folder on your board.

Library folders (copy the whole folder over to lib):

  • adafruit_magtag - This is a helper library designed for using all of the features of the MagTag, including networking, buttons, NeoPixels, etc.
  • adafruit_portalbase - This library is the base library that adafruit_magtag is built on top of.
  • adafruit_bitmap_font - There is fancy font support, and it's easy to make new fonts. This library reads and parses font files.
  • adafruit_display_text - This library displays text on the screen.
  • adafruit_io - This library helps connect the MagTag to our free data logging and viewing service

Library files:

  • adafruit_requests.mpy - This library allows us to perform HTTP requests and get responses back from servers. GET/POST/PUT/PATCH - they're all in here!
  • adafruit_fakerequests.mpy  - This library allows you to create fake HTTP requests by using local files.
  • adafruit_miniqr.mpy  - QR creation library lets us add easy-to-scan 2D barcodes to the E-Ink display
  • neopixel.mpy - This library is used to control the onboard NeoPixels.
  • simpleio.mpy - This library is used for tone generation.

Secrets

Even if you aren't planning to go online with your MagTag, you'll need to have a secrets.py file in the root directory (top level) of your CIRCUITPY drive. If you do not intend to connect to wireless, it does not need to have valid data in it. Here's more info on the secrets.py file.

Before we can use the Twitter API we need to register for a developer account. 

Go to https://developer.twitter.com/en.html. You should see a page something very like:

Click apply:

Then Apply for a developer account:

Select Exploring the API and click Next.

Fill out the form that gets presented, and clock Next. Verify the information, and click Next. Agree to the terms, and click Submit Application.

A verification email will be sent to your Twitter account's email address. Respond accordingly and you'll be able to create your app.

Creating an App

To access the Twitter API, you will need to create a Twitter app. On the Twitter Developer Portal, navigate to the Projects & Apps page and click Create App.

Name your app something unique. 

After naming your app, you'll be presented with your keys and tokens. Save all 3 keys and tokens somewhere safe on your computer, such as a text file on your desktop.

Open the secrets.py file on your PyPortal and add your Twitter app's Bearer token as twitter_bearer_token.

Your secrets.py file should look like this:

# 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

secrets = {
    'ssid' : 'home ssid',
    'password' : 'my password',
    'timezone' : "America/New_York", # http://worldtimeapi.org/timezones
    'github_token' : 'fawfj23rakjnfawiefa',
    'hackaday_token' : 'h4xx0rs3kret',
    'twitter_bearer_token' : 'YOUR_SECRET_TWITTER_BEARER_TOKEN'
    }

Secrets.py Setup

Open the secrets.py file on your CircuitPython device using Mu or your favorite text editor. You're going to edit this file to enter the Twitter Bearer Token you saved earlier.

  • Change twitter_bearer_token to your app's Twitter bearer token

Your secrets.py file should look like this: 

# 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

secrets = {
    'ssid' : 'home ssid',
    'password' : 'my password',
    'timezone' : "America/New_York", # http://worldtimeapi.org/timezones
    'github_token' : 'fawfj23rakjnfawiefa',
    'hackaday_token' : 'h4xx0rs3kret',
    'twitter_bearer_token' : 'YOUR_SECRET_TWITTER_BEARER_TOKEN'
    }

Code 

Click the Download: Project Zip File link below in the code window to get a zip file with all the files needed for the project. Copy the contents of the zip file and place them on the CIRCUITPY drive.

# SPDX-FileCopyrightText: 2019 Dave Astels for Adafruit Industries.
# SPDX-FileCopyrightText: 2020 Brent Rubell for Adafruit Industries.
#
# SPDX-License-Identifier: Unlicense
import time
from adafruit_magtag.magtag import MagTag

try:
    from secrets import secrets
except ImportError:
    print(
        """WiFi settings are kept in secrets.py, please add them there!
the secrets dictionary must contain 'ssid' and 'password' at a minimum"""
    )
    raise

# Set to the twitter username you'd like to fetch tweets from
TWITTER_USERNAME = "adafruit"

# Set to the amount of time to deep sleep for, in minutes
SLEEP_TIME = 15

# Set up where we'll be fetching data from
DATA_SOURCE = (
    "https://api.twitter.com/1.1/statuses/user_timeline.json?"
    "screen_name=%s&count=1&tweet_mode=extended" % TWITTER_USERNAME
)
TWEET_TEXT = [0, "full_text"]
TWEET_FULL_NAME = [0, "user", "name"]
TWEET_HANDLE = [0, "user", "screen_name"]

magtag = MagTag(url=DATA_SOURCE, json_path=(TWEET_FULL_NAME, TWEET_HANDLE, TWEET_TEXT))
# Set Twitter OAuth2.0 Bearer Token
bearer_token = secrets["twitter_bearer_token"]
magtag.set_headers({"Authorization": "Bearer " + bearer_token})

# Display setup
magtag.set_background("/images/background.bmp")

# Twitter name
magtag.add_text(
    text_position=(70, 10),
    text_font="/fonts/Arial-Bold-12.pcf",
)

# Twitter handle (@username)
magtag.add_text(
    text_position=(70, 30),
    text_font="/fonts/Arial-12.bdf",
    text_transform=lambda x: "@%s" % x,
)

# Tweet text
magtag.add_text(
    text_font="/fonts/Arial-Bold-12.pcf",
    text_wrap=30,
    text_maxlen=160,
    text_position=(
        5,
        (magtag.graphics.display.height // 2) + 20,
    ),
    line_spacing=0.75,
)

# preload characters
magtag.preload_font()

try:
    value = magtag.fetch()
    print("Response is", value)
except (ValueError, RuntimeError) as e:
    print("Some error occured, retrying! -", e)

time.sleep(2)
print("Sleeping!")
magtag.exit_and_deep_sleep(SLEEP_TIME * 60)

Once all the files are copied from your computer to the PyPortal, you should have the following files on your CIRCUITPY drive.

Code Usage

Every 15 minutes, the MagTag will attempt to fetch and display a new tweet from the Twitter handler specified in the code.

Then it goes into a deep sleep mode for 15 minutes to save energy.

 

Change the Twitter Handle

To display tweets from a specific Twitter account, change the following line in the code to the account you'd like to show tweets from:

TWITTER_USERNAME = 'adafruit'

Change the Sleep Time

After fetching and displaying a tweet, the MagTag goes into a deep-sleep mode for 15 minutes. Modify the following line in the code to reflect how long the MagTag will enter the deep sleep mode for, in minutes.

SLEEP_TIME = 15

Code Walkthrough

Data Sources

This project fetches data directly from Twitter's timeline API. A request is made to api.twitter.com to fetch the most recent status from a Twitter account, their full name, and their Twitter handle/username (such as @adafruit).

# Set up where we'll be fetching data from
DATA_SOURCE = "https://api.twitter.com/1.1/statuses/user_timeline.json?count=1&screen_name=%s"%TWITTER_USERNAME
TWEET_TEXT = [0, 'text']
TWEET_FULL_NAME = [0, 'user', 'name']
TWEET_HANDLE = [0, 'user', 'screen_name']

MagTag Library

The MagTag library makes it simple to create projects for the MagTag ePaper display. The code passes it the URL to fetch data from along with the JSON paths to retrieve the data.

magtag = MagTag(
    url=DATA_SOURCE,
    json_path=(TWEET_FULL_NAME, TWEET_HANDLE, TWEET_TEXT)
)
# Set Twitter OAuth2.0 Bearer Token
bearer_token = secrets['twitter_bearer_token']
magtag.set_headers({'Authorization': 'Bearer ' + bearer_token})

Display Objects

The code sets up a bitmap image background (a white background with a black Twitter logo) and text fields to hold the contents of the API response.

# Display setup
magtag.set_background("/images/background.bmp")

# Twitter username
magtag.add_text(
    text_position=(70, 10),
    text_font="/fonts/Arial-Bold-12.pcf",
)

# Twitter handle (@username)
magtag.add_text(
    text_position=(70, 30),
    text_font="/fonts/Arial-12.bdf",
    text_transform=lambda x: "@%s"%x,
)

# Tweet text
magtag.add_text(
    text_font="/fonts/Arial-Bold-12.pcf",
    text_wrap=40,
    text_maxlen=140,
    text_position=(
        10,
        (magtag.graphics.display.height // 2)+20,
    ),
    line_spacing=0.75,
)

# preload characters
magtag.preload_font()

Text Transform

Unfortunately, Twitter's API returns a twitter username without the "@" prefix. To add the @ prefix before a twitter username, the code uses an anonymous function (a "lambda") which is passed to the text_transform parameter in the magtag.add_text() function.

So, by calling text_transform=lambda x: "@%s"%x, we're creating a new anonymous function which looks like:

def x_function(x):

  return "@%s"%x

Update the Display

The main chunk of code attempts to fetch the URL from Twitter's API using magtag.fetch(). Then it parses out the data sources and displays the values on text labels.

try:
    value = magtag.fetch()
    print("Response is", value)
except (ValueError, RuntimeError) as e:
    print("Some error occured, retrying! -", e)

time.sleep(2)
print("Sleeping!")
magtag.exit_and_deep_sleep(SLEEP_TIME * 60)

The code exits and goes into deep sleep until the next SLEEP_TIME minutes. 

magtag.exit_and_deep_sleep(SLEEP_TIME * 60)

This guide was first published on Dec 29, 2020. It was last updated on Dec 29, 2020.