Minimatrix is a tiny (3cm x 3cm) battery powered LED matrix display, reprogrammable over infra-red. It displays marquee text and short animations, which can be programmed using an infrared remote control or from a computer via an Arduino or similar development platform. You can even use it as an interactive display by updating it live!
Minimatrix is available now on tindie! It’s $10 for a kit, $15 fully assembled, and $5 for a remote control.
For way more technical details about minimatrix, see this post.
Assembly instructions can be found here.
An owner’s / usage manual can be found here.