Wearable health monitoring technologies, including smartwatches and fitness trackers, have attracted considerable consumer interest over the past few years.

Not only has this interest has been mainly encouraged by the rapid demand growth in the wearable technology market for the ubiquitous, continuous, and pervasive monitoring of vital signs, but it has been leveraged by the state-of-the-art technological developments in sensor technology and wireless communications. The wearable technology market was valued at over $13.2 billion by the end of 2016 and its value is forecast to reach $34 billion by the end of 2020.

There are many sensors for measuring vitals of the human body which are essential for a doctor or a medic to know the health problems. We all know that doctor first checks Heart Rate to know Heart Rate Variability (HRV) and body temperature. But the current wearable bands and devices fail in the accuracy and repeatability of the measured data. This mostly happens due to miss alignment of fitness tracker and erroneous reading etc. Most use the LED and Photodiode based Photo Plethysmography (PPG) sensors for the heart rate measurement.