There are 3 rings of 12 LEDs on the left side of the PCB, which are used as an analog clock displaying Hours, Minutes and Seconds. A 17x11 LED matrix also displays the time and allows for configuring settings.
A light sensor provides for a smooth experience in brighter and darker environments.
The CardClock time can be set manually or if on WiFi, syncs NTP time every 3 hours. It also keeps track of time using the onboard Real-Time-Clock. Unplug your clock? No problem, the super-capacitor keeps the RTC powered for more than 2 days.