Altered circadian rhythms are commonly reported among individuals with psychiatric disorders, such as bipolar disorder, anxiety, depression. Depression is a common mental disorder. Globally, it is estimated that 5% of adults suffer from depression. Up to 20% of people in industrial societies work night shifts, commercial airlines often crossing time zones carry more than half of the world's population a year, and even much greater proportion of the population regularly experiences "social jet lag". All these contribute not only to sleep disorders, but also to circadian disruption via phase advance, delay and instability, blunted amplitude, etc. Since, chronotherapy proves effective in certain mental health conditions, we see it is important to use such affordable tool as consumer devices to keep users informed on the stability as well as the early signs of desynchronisation of their circadian rhythms.