https://en.wikipedia.org/wiki/Refreshable_braille_display

https://www.youtube.com/watch?v=9yLZRPXJ8lo  HumanWare Brailliant Braille Display  8:57 (see also: https://www.youtube.com/user/HumanWareTechnologie/videos )

https://www.youtube.com/watch?v=FL8AxMZgQiA   Demonstration of the Vario Ultra Braille Display from Baum 10:22 (see also: https://www.youtube.com/user/ChiLighthouse/videos  The Chicago Lighthouse Adaptive Technology Center)