Utilizing Smartphone as Colorimetric Sensor in Detecting Stress Level

Stress is a human reaction that occurs when there is a physical or emotional change in the environment that necessitates adaptation. The human body produces stress hormones known as cortisol. When we are under stress, the amount of cortisol in our bodies increases. Cortisol levels can also reveal health information. In this paper, we developed an Android application on a smartphone as a colorimetric sensor to measure cortisol concentration, which was correlated with stress level as part of the development of a wearable cortisol biosensor. The smartphone’s Android apps can detect changes in the color of the biosensor caused by cortisol concentration changes. This color will be translated by a smartphone into Red, Green, and Blue (RGB) values, which will then be translated into the stress level.