For the most part, the build is what you would expect: a 16×8 LED Matrix display driven by a TLC5920 LED driver, with an Arduino that uses a DS1307 RTC (real-time clock) with a coin cell battery ...

He started with a prototype that uses a PIC 18F4580 microcontroller connected to a MAX7221 LED driver, which gave him control over some dot matrix displays to test the wiring and sample script.

Okay, I knew this would happen - one Arduino clock leads to another. Take a look at a clock that tells the time in terms of the first 192 digits of Pi, via a 32 x 8 LED matrix... Dubbed the Pi Day ...