I worked at a company in the late 90's that made some of (or first) Braille computers. The braille dots were actuated with Piezo driven at over 200 volts. The piezo compound was proprietary and supposedly the blending process was done by two or three old women in Germany. Anyhow, we had a retired French physicist (French civilian nuclear program) working on driving braille cells with Nitinol under a SBIR grant. Unfortunately we were not able to get past prototype stage. The was a very interesting place to work. Almost forgot the lead- I still have a package of "Muscle wire" that he gave me.