Circadian watch

by Jonathan Ravasz

The hypothalamus regulates body temperature between 36°C and 38°C over each 24 hour cycle. During the normal circadian rhythm, sleep occurs when the core temperature is dropping. Sleep usually begins when the body heat loss is maximal. The average adults lowest temperature is about 5AM, two hours before waking time.


I propose a “watch” that measures the human body’s cycle, circadian rhythm by body temperature. The users would be informed about the phase of the day not by the conventional 24 hour clock, but their own biological rhythm.

The prototype should consist of an Arduino Lilypad, bluetooth module, lithium-ion battery, set of LEDs indicating temperature and a bluetooth in-ear temperature sensor.

Leave a Comment

Your email address will not be published. Required fields are marked *