If you are planning to implement any electronic moving display system that is activated by movements in its surroundings then just have a look on the project posted by Jer from Volts and Bytes, where an Atmega8 is used to activate a Sure Electronics 0832 LED matrix display when motion is detected by the attached PIR sensor. Check the link for complete circuit schematics and firmware.
“This consumes less power than those electronic moving display system without the motion triggering system.”
It is perfect solution to put it near entrances where people would see some welcome message. Or use projects starting point for more great projects that would include sound, or mechanical movement triggered by PIR sensor.