I want to make an analog subway countdown clock. The idea is to have an ordinary clock with three hands. These hands will point to the number of minutes before the next, second next, and third next train arrives at my local subway station (one of the L stations in Brooklyn, NYC).
I was thinking to implement this using a Raspberry Pi. The software part is easy; however I have no idea how to get started on the hardware part. Is it possible to get a motor which can control three clock hands completely separately but on the same shaft? Or is there another mechanism that could address this problem?
I did some research, and you can buy hardware to control an hours-minute-second clock, but the problem is that you can't decouple the hands and get separate control on each of them.