If I asked you today to rotate a volume control remotely, for example, you might offer up an open loop stepper motor or an RC-style servo ... in some equipment: a synchro. The synchro dates ...

[M-byte] wrote in to tell us about the Lego Synchro Drive. Although not a new ... but this drive is made using only Lego Technic parts. The machine’s motion is quite pleasing.