What will this do?

A Raspberry Pi powered HUB75-Matrix real-time UK train departure board with UI. Uses Staff Data for additional functionality.

Configurable via a light-weight web-page or the command line you can select:

• All trains from a station
• All trains from a station on a specified platform
• Whether to show Network Rail alert message.
• The frequency of display update
• Frequency of toggle between 2nd and 3rd departure
• Many other options…

Default display:

• The next train with calling points, operator and formation
• Any delay-related messages and cancellation reasons
• Location of the next service
• The following two departures – destination and departure times

Options to display

• Station the departure board is configured for
• Departure platform
• Estimated departure time for calling points
• Any National Rail messages for the station

There are some limitations with using this hardware which I suspect don’t apply to commercially-available units, however for the cost it’s a great result!

Rough Costs – £50 for the Raspberry Pi (although bargains to be had on eBay), £14 for the adapter, £18 per-panel from Ali Express. I’ve left out the power-supply as this depends on what you have to hand.

Some Background

Being a life-long train fan I’ve always wanted my own departure board, and as a regular commuter one which shows my usual route.

Over the years I’ve looked at flip-dot displays and various other types and saw LED dot-matrix displays become available for purchase. These look amazing… however the price is offputting, as is the monthly-subscription some require.

My thought – “How hard can it be”.

And here we are.

Step 1 – Get the Hardware

The TL:DR with some example links to the products (I’m not plugging any vendor here!).

• Some P2, 5V, 128*64 pixel colour modules with a HUB75E interface (3 works well – the video above has 4)
• A Raspberry Pi 4 (1GB is fine)
• Either an Adafruit RGB Matrix Bonnet or an Electrodragon 3-port RGB Matrix board (latter is great value)
• A 5V power-supply capable of delivering at least 5 Amps

Too much for this page, so there’s detail on the Hardware page.

Step 2 – Set up the Raspberry Pi

Switch off Anything you Don’t Need

1. Set dtparam=audio=off in /boot/firmware/config.txt
2. Add isolcpus=3 to the end of the parameters in /boot/firmware/cmdline.txt to isolate a CPU.
3. Example – console=serial0,115200 console=tty1 root=PARTUUID=9f23843a-02 rootfstype=ext4 fsck.repair=yes rootwait cfg80211.ieee80211_regdom=GB isolcpus=3
4. Remove unecessary services with sudo apt-get remove bluez bluez-firmware pi-bluetooth triggerhappy pigpio

Then run lsmod and to check for the snd_bcm2835 module.

$lsmod | grep snd_bcm2835
snd_bcm2835            24576  0
snd_pcm               139264  5 snd_bcm2835,snd_soc_hdmi_codec,snd_compress,snd_soc_core,snd_pcm_dmaengine
snd                   110592  6 snd_bcm2835,snd_soc_hdmi_codec,snd_timer,snd_compress,snd_soc_core,snd_pcm

If it’s there then blacklist it:

cat << EOF | sudo tee /etc/modprobe.d/blacklist-rgb-matrix.conf
blacklist snd_bcm2835
EOF

sudo update-initramfs -u

Finally reboot - sudo reboot - to get a nice clean and sparkly install.

Note At the rsk of stating the obvious, when adding options to cmdline.txt add to the end and do not put in a newline.

In no particular order:

• Git
• JSON for modern C++
• curl (should be there already)
• curl C++ wrappers

sudo apt install git
sudo apt install nlohmann-json3-dev
sudo apt install libcurl4
sudo apt install libcurlpp-dev

Take a clone of HZellers RPI RGB Matrix repository and compile the library

git clone https://github.com/hzeller/rpi-rgb-led-matrix.
cd rpi-rgb-matrix
make

A pre-emptive read of the Troubleshooting section will help you get ahead of issues.

Enjoy the demos in the examples-api-use directory. If you've got the configuration described here then you can start with this:

(you'll need to drop the --led-gpio-mapping=adafruit-hat if you're not using an Adafruit Hat)

sudo ./demo -D9 --led-rows=64 --led-cols=128 --led-chain=3 --led-gpio-mapping=adafruit-hat

Have fun with the demos!

Step 3 – Set up the Data-Feed

You’ll need to register for an account – do this as an individual rather than a company.

Once you’ve got an account you’ll need to subscribe to two data-sets:

• Staff Data
• Reference Data

Find these via the Data Products Catalogue.

Search for Live Departure Board – Staff Version – and go to the Specification tab on the page

Click on /LDBSVWS/api/20220120/GetArrDepBoardWithDetails/{crs}/{time} – this is the departure data we’re using.

Copy the Consumer Key and save it to put in your config file.

Search for Reference Data – and go to the Specification tab on the page.

Note that there are a number of Reference Data sources available – the one you want is just called ‘Reference Data’.

Click on /LDBSVWS/api/ref/20211101/GetReasonCodeList – this is the delay/cancellation reason data we’re using.

Copy the Consumer Key and save it to put in your config file.

Step 4 – Install the Departure Board Software

Download and build from my Github Departure Board repository

git clone https://github.com/jonmorrissmith/RPi_DepartureBoard
cd RPi_DepartureBoard
chmod 755 setup.sh
./setup.sh

This will build the software, configure the UI, create config files and ensure permissions are correctly set on directories.

Start the UI server

./run.sh

You should see:

Starting server on port 80...

Which means you can go to http:// and start using your display!

First Time Use and Configuration

Set the following in the UI

debug_mode      \\ true/false for on/off
debug_log_dir   \\ where to store the debug logs and JSON output from the API

location   \\ The CRS code for the station whose departures you want to show
platform   \\ Leave blank for all platforms or populate for a specific platform

ShowCallingPointETD   \\ If set to Yes will display departure times after each calling point
ShowMessages          \\ If set to Yes will display Network Rail message for your departure station
ShowPlatforms         \\ If set to Yes will display the platform for the departures
ShowLocation          \\ If set ('from') will display at the bottom (alternate with Messages)

StaffAPIKey           \\ The Staff Departure Board key from Rail Data Market Place
DelayCancelAPIKey     \\ The Delay/Cancellation Reference Data key from Rail Data Market Place

fontPath  \\ Path to fonts - you can use the matrix package (/home//rpi-rgb-led-matrix/fonts/7x14.bdf)

calling_point_slowdown       \\ Lower the number, the faster the calling-points scroll
nrcc_message_slowdown        \\ Lower the number, the faster the Network Rail messages scroll
refresh_interval_seconds     \\ How often the API is called to refresh the train data
third_line_refresh_seconds   \\ How often the third line switches between 2nd and 3rd departure
Message_Refresh_interval     \\ How often any Network Rail messages are shown
ETD_coach_refresh_seconds    \\ How often the top right switches between ETD and number of coaches
third_line_scroll_in         \\ If true 2nd/3rd departures scroll in rapidly from the right when they change

matrixcols=128           \\ Number of columns in an LED matrix panel
matrixrows=64            \\ Number of rows in an LED matrix panel
matrixchain_length=3     \\ Number of panels you've got chained together
matrixparallel=1         \\ Number of chains you've got running in parallel
matrixhardware_mapping   \\ See hzeller documentation - set to adafruit-hat-pwm for the Adafruit bonnet
gpio_slowdown=2          \\ Sometimes the Pi is too fast for the matrix.  Fiddle with this to get the right setting.

first_line_y     \\ pixel-row for the first line of text
second_line_y    \\ pixel-row for the second line of text
third_line_y     \\ pixel-row for the third line of text
fourth_line_y    \\ pixel-row for the fourth line of text

Scroll to the bottom and click on Save and Restart.

This saves your configuration (to ‘config.txt’) and (re)starts the display.

You can Save as Default and Rest to Default to allow you to revert changes.

It’s unlikely that you’ll need to change these, but they’re available if you need to.

Detail of the parameters is available in the RGB Matrix documentation.

led-multiplexing
led-pixel-mapper
led-pwm-bits
led-brightness
led-scan-mode
led-row-addr-type
led-show-refresh
led-limit-refresh
led-inverse
led-rgb-sequence
led-pwm-lsb-nanoseconds
led-pwm-dither-bits
led-no-hardware-pulse
led-panel-type
led-daemon
led-no-drop-privs
led-drop-priv-user
led-drop-priv-group

Additional Information

Simply remove the -d option from the Executable_command_line line in ui-config.txt

Change the port in ui-config.txt.

Note that the executable needs root to access the RGB matrix.

You can edit config.h to hard-code values for parameters which are in config.txt

If you do this then it’s easiest to run

make clean
make all

which will recompile the executable with your defaults.

Three options which also support a ‘-d’ option for debugging information

Use the hard-coded configuration in the executable

sudo ./departureboard

Use the hard-coded configuration in the executable and specify origin

sudo ./departureboard KGX

Use the configuration file

sudo ./departureboard -f

Combination of the above

sudo ./departureboard KGX -f -d

Happy to help – create an issue on github or email the user ‘train’ at anotherpartialsuccess.com

Helpful Links for debugging RGB Matrix Issues

• Changing parameters
• Troubleshooting
• Contact me via GitHub