These pieces are from the old and now abandoned airport of Athens . These units were taken by gypsies for scrap. Luckily, one day a patron of fine things noticed a truck of gypsies not far away from were he lived and saw these units at the back of their truck. After a bit of bartering these units were saved from an untimely demise and are now available for your use.
Each split flap display has a collection of forty flaps on which the characters or graphics that are silkscreened. These flaps are precisely rotated to show the desired character or graphic. These displays are often found in railway stations and airports, where they serve as flight information display system and typically display departure or arrival information, although digital equivalents are far more common now.
Sometimes the flaps are large and display whole words, and in other installations there are several smaller flaps, each displaying a single character. The former method is limited to the words it can display on the flaps, while the latter system is not, and output messages can be changed without the need for the addition or replacement of flaps, although images cannot. During a power loss or disruption the display will freeze.
See our write up HERE on how we reverse engineered the control and operation of these displays with modern micro controllers.