This replica uses LEDs driven by an Arduino Nano and a real-time clock. Since the RTC gives hours from 0-23 and minutes and seconds from 0-59, a couple of shift registers and some modulo ...

This presented a problem, as [Frugha] wanted to control the clock with a single Arduino Nano. Even charlieplexing won’t get you that many I/O lines. The solution was a nifty little chip called ...

Apart from understanding the Arduino's code language ... on the Nano and Micro are entirely different. The Nano runs on an ATmega328 with a clock speed of 16 MHz, flash memory of 32 KB, SRAM ...