e-ink Subway & Weather Display

A Raspberry Pi-powered e-ink display showing real-time subway arrival times and weather forecasts. Perfect for mounting on your wall to check train times and weather before heading out.

Full Post here.

Features

• Real-time subway arrival times
• Current weather and 3-day forecast
• Debug mode with automatic image preview
• Native e-ink display support on Raspberry Pi

Getting Started

Hardware

• Raspberry Pi 4b+
  • SD Card, power supply, (optionally keyboard, mouse, hdmi cord, etc.)
• Waveshare 9.7inch E-Ink display HAT for Raspberry Pi
• Frame (optional)
• Custom Mat (Optional, but I got mine from AmericanFrame.com)

Raspberry Pi Setup

0. Figure out how you're going to connect to the Raspberry Pi
1. Install UV
2. Enable the SPI interface
3. Attach the e-ink display to the Raspberry Pi

To test the display on Raspberry Pi:

git clone https://github.com/sambroner/subway-eink.git
cd subway-eink
uv sync
uv run test.py

Installation

1. Install uv (if not already installed)
2. Install dependencies:

   uv sync

3. Set up .env file (copy from .env.template)

Running on your wall

1. Set up a systemd service

Running

If DEBUG=true in your .env:

• Images will be saved to debug_output/current_display.png
• Your system's default image viewer will automatically open and update with each refresh
• The image viewer will refresh automatically when new data arrives

If DEBUG=false:

• On Raspberry Pi: The e-ink display will update
• On other platforms: An error will be raised (e-ink display only works on Raspberry Pi)

To run:

uv run runner.py

CairoSVG

• CairoSVG is used to convert SVGs to PNGs for the display.
• On mac, you may need to manually compile Cairo: https://stackoverflow.com/questions/36225410/installing-cairo-and-pycairo-mac-osx

Display Modes

Figuring out the right display mode was annoying. The full spec is here.

To Do

• Consider checking if the wait time still makes sense and then refresh. E.g. It's 11am. Train Arrives at 11:04 and there's no update. When time turns to 11:01, even if no update, refresh.
• Fix hourly weather... seems like it's only 100% or zero?

Credits

• IT8951 library by GregDMeyer: https://github.com/GregDMeyer/IT8951

Setting up as a service

To have the display start automatically on boot:

sudo systemctl restart subway-eink.service
sudo systemctl stop subway-eink.service

[Unit]
Description=Subway E-Ink Display Service
After=network.target

[Service]
Type=simple
User=sambroner
WorkingDirectory=/path/to/repo
ExecStart=/path/to/uv run runner.py
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target