With Twitter being purchased and renamed X, it is likely this guide no longer functions as it did when it was written. It will be kept up for reference only - do not rely on thie project to work due to extensive changes by X.

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.

MagTag dev board with enclosure pieces, four magnet feet, and lipoly battery
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...
Out of Stock

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

Angled shot of Adafruit MagTag development board with ESP32-S2 and E-Ink display.
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...
Out of Stock
Lithium Ion Polymer Battery 3.7v 420mAh with JST 2-PH connector and short cable
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...
Out of Stock
Angled shot of four magnet feet.
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:

Acrylic + Hardware Kit for Adafruit MagTag showing contents
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.

USB Type A to Type C Cable - 1ft - 0.3 meter
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...
Out of Stock
USB Type A to Type C Cable - approx 1 meter / 3 ft long
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.

One of the great things about the ESP32 is the 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. 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, 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.

CIRCUITPY

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.

Don't share your settings.toml file! It has your passwords and API keys in it!

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!

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'
    }

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 MagTag_Twitter/ 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:

CIRCUITPY
# 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, ConnectionError, OSError) as e:
    print("Some error occured, retrying! -", e)

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

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 Jul 21, 2024.