The Desktop Billboard
Many operator controls are built into the software. You can choose any one of 4 different 50-character messages, you can make the display brighter or dimmer, you can vary the scroll rate, and you can select two different built-in animation effects to run at the end of your message: a bouncing ball (like "Pong") or something that looks like an exploding dot. When entering characters for your message, you can insert, delete, and scroll forward or backward. Messages are retained in non-volatile memory when the Billboard is turned off.
As with my other devices, I have personally made the cabinet, designed the circuitry, and written the software.
The Desktop Billboard will run on its own internal batteries or an AC adaptor.