How was this clock made?

Hi everyone, I found this clock , the D/A clock by Alvin Aronson, and I am wondering if anyone knows how to make this clock or if anyone knows how he made it?


Picture of How was this clock made?
ehfo (author) 5 years ago
ahhh, thanks!
Kiteman5 years ago
It looks like a set of small servos lifting and lowering the segments in the desired sequence.

Kiteman Kiteman5 years ago