Flippin’ tech 

30 November 2015 tbs.pm/8132

The Vintage Technology Association

If you ever wondered how the BBC flip-dots schools’ programmes countdown clock worked, the Vintage Technology Association has revealed all.

A flip dot display uses an array of magnetic disks suspended above a matrix of coils to display alphanumeric data. Each coil has a U-shaped bar passing through it, which stores the magnetic state imparted when an electric current passes through the coil. The U-bars are connected to the pivot points of each magnetic disk, causing the disks to flip to match the magnetic state of the bars.

You can glimpse it in action here:

Ferranti-Packard Flip Dot Display [AnubisTTP/The Vintage Technology Association] via Dave Jeffery/Roddy Buxton