The “Simply” Perfect Clock #piday #raspberrypi - Adafruit Blog

TL;DR

Lee Hutchson wanted a simple clock that never needed setting, specifically a red seven-segment display that could automatically sync with an atomic time source. After failing to find a ready-made solution that met all his requirements, he decided to build his own clock using a Raspberry Pi, a 3D printer, and a red 1.2” four-digit seven-segment display with an I2C backpack.