Development potential of mHealth (mobile health) applications can be improved with the introduction of a miniature optical blood-flow sensor that could sense stress levels, help prevent dehydration and avoid altitude sickness. mHealth applications include blood-flow sensing earbuds, a wearable device for heatstroke prevention and a wearable device for mountain climbers.

The sensor works by measuring the blood-flow volume in the subcutaneous tissue through contact with the ear, finger or forehead. It utilizes a phenomenon called the Doppler shift through the measurement of light frequency variations when light is reflected from the blood vessels.

 
optical sensor diagram kyocera(cr) Figure 1: Sensor utilizes the relative shift in frequency and the strength of the reflected light to measure blood-flow volume.  

A high signal-to-noise ratio (S/N), small size and low power consumption (output: 0.5mW) would enable an easy integration with mobile devices and wearables. The sensor which measures only 1mm x 1.6mm x 3.2mm will be offered by Kyocera in module sample by April 2017 and is projected to be introduced to the market by March 2018.