It's a biorhythm clock using Arduino Nano.

A biorhythm is a theoretical process by which the human body and mind are regulated according to set patterns. Biorhythms are usually separated into three distinct groups. The emotional, mental, and physical cycles. Classically, the lengths of these cycles are 28 days, 33 days, and 23 days respectively.

The default date of birth is set in the sketch. To change it, you need to press the knob for more than three seconds, and then change year, month and day using a double-click on the knob.

The LED will give you the Emotional, Physical and Intellectual status, calculated using the date of birth and the current date and time maintained by the RTC clock.