An emoji slideshow on the Sense HAT

EmojiLoop is a small pixel-art slideshow for the Sense HAT LED matrix. It cycles through five 8×8 icons — a smiley, a heart, a skull, a Space Invader-style alien and an up arrow — every 3 seconds.

Source code: projects/EmojiLoop/EmojiLoop.java

How it works

Each icon is defined as a flat int[] of length 64 (8 columns × 8 rows). To keep the source readable, the code uses short one-letter constants:

• o — off (transparent / background)
• K — black
• Y — yellow
• R — red
• W — white
• G — green
• B — blue

Every row of the array is written out with these constants, which makes each sprite look like ASCII art in the source file. That's a nice pattern to know: it makes it very easy to hand-draw new icons.

The main loop:

1. Opens the Sense HAT.
2. Iterates over the array of sprites and their names.
3. For each sprite, prints its name to the console and calls hat.setPixels(sprite) to draw all 64 pixels at once.
4. Sleeps 3 seconds, then moves to the next icon and eventually restarts from the beginning.

Running it

This script depends on a specific branch of pi4j-drivers (my igfasouza branch), so clone and install it locally first:

git clone -b igfasouza https://github.com/igfasouza/pi4j-drivers.git
cd pi4j-drivers
mvn install

Then run it with JBang on a Raspberry Pi with a Sense HAT attached:

jbang projects/EmojiLoop/EmojiLoop.java