Peggy 2 is our intelligent, Arduino-compatible (“freeduino” based), multiplexed 25 x 25 LED matrix, supporting up to 10 mm LEDs (or up to 5 mm LEDs in the Peggy 2LE version). It supports single-color LEDs at each point in the matrix, but you can mix and match different color LEDs throughout the matrix, and you don’t have to populate every LED location.
Since the whole matrix is available to control, it can be used to make an interesting clock in a lot of different ways.
One of the things that is sometimes helpful on a clock is to get slightly better precision than is available from a regular quartz crystal, and we’ve been using Macetech’s ChronoDot module on our Bulbdial clock kit. However it’s almost as easy to add the ChronoDot to the Peggy, and here’s how to do so.