“Split-flap displays are electromechanical display devices, which were common in airports or railway stations a few years ago.Unfortunately, most of them are gone and replaced by LED displays. Why not create a DIY version of it?
As mechanical devices they are rather complex and subject of mechanical wear-out. But Split-Flap displays have many advantages over their LED counterparts: no power required if the display is static, good visibility and contrast, and the flapping sound draws attention if information changes.”