A scrolling information display for the Pimoroni Unicorn HAT/PHAT on Raspberry Pi.
By Andrew Wedgbury wedge@sconemad.com

To start with, clone this git repo!

Install the unicornhat Python module from Pimoroni following the [instructions here] (https://github.com/pimoroni/unicorn-hat).

unicorn-scroller.py uses the PIL module.
The astro message script uses the pyephem module.
You can install these via pip with:

sudo pip install PIL
sudo pip install pyephem

You also need a font to use when displaying text. It's difficult to find a font that looks good at 8 pixels high - The best I've found is Minecraftia-Regular, which you can download from http://www.dafont.com/minecraftia.font Unzip the font into the same directory as the script. You can also try out some different fonts - there are plenty available for free online. Unzip your chosen font into the same directory and modify the "font" and "font-offset" variables near the top of the main program.

You'll find various other variables defined at the top of unicorn-scroller.py, which you can use to set the display orientation, brightness, background colour and scroll speed.

To run from the command line:

sudo python unicorn-scroller.py

To run on system boot, add the following to /etc/rc.local (before the "exit 0" line at the end):

(cd /home/pi/unicorn-scroller && python unicorn-scroller.py)&

Being sure to change /home/pi/unicorn-scroller to the actual directory where you checked out the files if different.

The program scrolls messages generated by scripts located in the messages subdirectory. Each script outputs its message in a simple format, consisting of text and the names of image files located in the images subdirectory.

The following message scripts are available: (The example images shown below were generated by saving the PIL Image object as a PNG file, and scaling up by 2x, and use the Minecraftia-Regular font)

Example:

Displays the current time.
Make sure you have your timezone set correctly!

Example:

Displays the current date.

Example:

Displays the current weather conditions plus a 3 day forecast.
This uses BBC weather feeds, you will need to edit the script and add your location ID, the previous link should explain how to get this.

Example:

Displays some astronimical information calculated using pyephem - moon phase, sunrise and sunset times.
You will need to set the 'loc' variable near the top of this script to describe your location for this to be accurate.

Example:

Displays a short fortune cookie message generated by the unix fortune program.

The order and frequency of the messages to be displayed is determined by a set of symbolic links in the messages subdirectory. The program looks for links named in the form of two numbers separated by a dash, which are interpreted as a denominator, d and remainder r in the following formuala:

i % d == r

Where i is an integer which starts at 1 and is incremented for every loop, and % is the modulus operator.

The default configuration is the following set of links:

01-00 -> time
16-00 -> date
16-04 -> weather
16-08 -> date
16-12 -> astro
99-00 -> fortune

So the time message is shown for every loop, date is shown every 8 loops, and weather and astro on every 16 loops. The fortune message is shown less frequently, on every 99 loops. You can change these links as required, by removing (using the rm command) and adding (using the ln -s command). For example, to show the fortune message every 50 loops:

cd messages
rm 99-00
ln -s fortune 50-00

You can of course modify the message scripts or add new ones as required!