• Equipment
• Testing the display
  • Install BCM2835 C library
  • Test the OLED
• Running the departure board
  • Prerequisites
  • Connecting the display
  • Launch time!
• License

You can test the departure board using an emulator driven by pygame without the need for any additional hardware.

sudo apt install python3 python3-pip python3-pil python3-venv python-is-python3 libjpeg-dev zlib1g-dev libfreetype6-dev liblcms2-dev libopenjp2-7 libtiff5
python -m venv venv
pip install -r requirements.dev
python src/main.py --emulate GTW

• Raspberry Pi 4
• SD1322 256x64 SPI OLED display
  • 4 pin SPI, with Raspberry Pi dupont cable

You can perform a basic sanity check on your SD1322 display before using it as a departure board.

The BCM2835 was used on the 1st gen Raspberry Pis but future models have maintained backwards compatibility in terms of GPIO access to the extent that the kernel developers have chosen to report the BCM2835 as used in even modern Pis.

We need to install a C library in order to access the GPIO pins and other features of the Pi within our application.

cd reference/bcm2835-1.71
./configure
make
sudo make check
sudo make install

These commands will build, test, and install the BCM2835 C library onto your Raspberry Pi. If you encounter any issues, you might need to install some additional dependencies:

sudo apt install autoconf build-essential
autoreconf -f -i

If you're using the same OLED display as me, the seller provides a test program which you can use.

You'll need the BCM2835 library from the last step already installed.

cd reference/SPI_Interface
make
sudo ./oled

The test app should cycle through various monochrome bitmaps, before displaying the time and an cycling advert for "www.buydisplay.com".

On Ubuntu, you can run the following commands in a terminal to install the required prerequisites for your departure board

# Python and Luma prerequisites
sudo apt install python3 python3-pip python3-pil python3-venv python-is-python3 libjpeg-dev zlib1g-dev libfreetype6-dev liblcms2-dev libopenjp2-7 libtiff5

# Enable non-root access to the SPI port for your current user
sudo usermod -a -G spi,gpio,i2c $(whoami)

# Install dependencies
python -m venv venv
pip install -r requirements.txt

This may be different depending on your display, but this works correctly with mine.

Note

RPi pin numbers in the table below are the GPIO pin numbers and not the physical pin numbers on the header.

Run the script!

# Replace GTW with any CRS codes
python src/main.py GTW

Running the departure board as a service allows it to be started automatically when your system boots up.

You can configure the station CRS in the departure-board.service station:

# for Gatwick Airport (GTW)
Environment="STATION_CRS=GTW"

Run the following commands to set up the service:

cp departure-board.service ~/.config/systemd/user/
systemctl --user enable departure-board.service
systemctl --user start departure-board.service
loginctl enable-linger $USER

Starting the service can take up to 5 minutes depending on your device and internet connection. This is because the service creates a virtual environment and installs the dependencies.

If something goes wrong, you can watch the service logs:

journalctl --user -fu departure-board.service

You can modify the service file at ~/.config/systemd/user/departure-board.service. If you modify the service file you need to reload the systemd daemon:

systemctl --user daemon-reload
systemctl --user restart departure-board.service

Rather simple:

git pull
systemctl --user restart departure-board.service

This repository is licensed under the MIT license, but I do appreciate some form of attribution if you reuse this elsewhere.

The CustomPixelFont and CustomPixelFontSmall in src/assets were created by me using free (for now?) software called PixelForge (download permalink) developed by Sergi Lázaro.