These files power a 64x32 RGB matrix display that shows arrival times for the New York City Subway or the Washington DC Metro Rail. I am currently using an Adafruit Matrixportal S3 micocontroller. It was vaguely inspired by Tidbyt products, but mostly just the form factor. You can find instructions on how to set this up yourself at the bottom.
New York City has the most extensive public transportation system in the United States, but due to its age (over 100 years old!) it is frequently in need of major maintenance which disrupts or delays service. To avoid needlessly waiting for trains on the platform, this display shows the next two trains traveling in one direction (the way I'm usually going) from the station closest to my apartment. Pushing the built-in Up button on the microcontroller displays the next four trains going in both directions.
The default screen also shows the time, temperature and AQI level. The AQI icon is color coded to signal the recommendations put out by the US gov. The subway line icons (known as 'bullets' in official parlance), will flash an alert symbol if the transit agency has issued an alert for that line. Pushing the onboard Down button will scroll the alerts along the bottom of the display.
Originally, I used an Adafruit Matrixportal M4, but it doesn't have enough memory for all the information and would frequently crash. I also would like to add additional functionality, so the additional memory is necessary.
The NYC Subway and Washington DC Metro use protocol buffers for their data. The packages needed to parse the datafeeds are too large for a microcontroller, so I built a simple Flask app that prepares the data for the display. That app is hosted on Python Anywhere. This setup only requires you obtain a free API key from the MTA or WMATA. Specifying the subway lines and station that's displayed is handled by headers in the API call to the Flask app.
NYC Subway routes are organized into two travel directions: North and South and looking at a map this is fairly easy to figure out which direction you would want displayed. Washington DC's Metro is a little more complex and in the official data feed trains are listed as direction 0 or direction 1. I have mapped these to roughly trains that end in the North or East and ones that end in the South or West.
I’ve been thinking about adding a dial that would allow switching between more than just two screens, but I haven’t thought of what other sort of information I’d like to display. I would also like to build a case for it.
The data delivered by the Flask app includes information on the terminal station, and displaying this or filtering trains based on it could be useful for users who need that level of specificity.
I’d also like to add support for other transit agencies, so if you live in a city where this would be useful, please contribute!
These are the components I used in my build:
- Adafruit Matrixportal S3
- 64x32 RGB LED Matrix display - 4mm pitch, similar to this one
- A diffusion panel
- Wall power adapter to USB C (5V 2.5A), similar to this one. Note: the linked adapter also requires a Micro B USB to USB C adapter. If it's out of stock, it is also available here.
- UGLU Adhesive Dashes used to adhere the diffusion panel to the LED Matrix display. Adafruit recommended.
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Follow the instructions on this page to prepared the display and install CircuitPython. Download the library files. Ensure the following are placed inside the
libfolder when installing libraries:- adafruit_bitmap_font/
- adafruit_bus_device/
- adafruit_display_shapes/
- adafruit_display_text/
- adafruit_esp32spi/
- adafruit_imageload/
- adafruit_io/
- adafruit_matrixportal/
- adafruit_minimqtt/
- adafruit_portalbase/
- adafruit_connection_manager.mpy
- adafruit_fakerequests.mpy
- adafruit_lis3dh.mpy
- adafruit_requests.mpy
- neopixel.mpy
- adafruit_ticks.mpy
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If you are setting this up in Washington, DC, sign up for a developer account and get an API key. If you are setting this up for NYC, no API key is necessary.
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Create an API key for your
Flaskapp, it can be anything, it just has to match when making requests. -
Sign up for a an account on pythonanywhere.com and follow these instructions to deploy the
Flaskapp in the repo (the file calledtransit_api.py). Make sure to fill in your API keys in theenvar_template.pyand then rename it toenvar.pybefore uploading it to pythonanywhere. Finally, uploadstation_dict.pyto the same directory astransit_api.pyandenvar.pyon pythonanywhere.com. -
Copy the
fontsfolder to the root directory on the Matrixportal. -
Copy the
imgfolder for your selected transit system to the root directory. -
Download and fill out the fields in
secrets_template.pyaccording to the inline instructions. -
Rename
secrets_template.pytosecrets.pyand copy it to the root directory. -
Copy the
code.pyto the root directory. -
It is best practice to use a serial monitor (Ex. from the Arduino IDE) to ensure the code is running correctly before attaching the LED Matrix display as computer supplied USB-C power is often not enough to power the board and display. This can make it appear that the code is failing when the issue may actually be insufficient power.
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Enjoy not waiting on the platform.
If you used a Matrixportal S3, it has three buttons built into the board. From top to bottom they are: RESET, UP and DOWN. Here is the current functionality of each button:
RESETwill reset the device and will reload the code, it's useful in case the board looses its wi-fi connection or other errors.UPwill change the display to show the next four trains in both directions, as seen in the example gif above.DOWNscrolls any active alerts on the lines selected during setup.
This project is licensed under the GNU v3.