A Portable Device for Measuring Heart Rate in Comparison with the Pressure Applied for Light Penetration in Skin Surface

Abstract

This paper describes a new technique which measures the extent of light penetration into a skin by measuring the force applied on the source and detector to push them deep into the skin for NIR Spectroscopy. The current research analyses the transmitted or reflected light from the skin on an account of how much force was applied to push the transmitter and receiver and the result shows a linear increase in both the quantities. To achieve this, a new device has been prepared containing two different LEDs having different wavelength surrounded by four different photodiodes. To measure the force, a stain gauge has been installed on the opposite sides. The sensing unit is followed by the signal conditioning and microcontroller circuit. In addition to this, the paper also shows the waveforms of PPG signal in accordance with the applied increased pressure and shows different types of shapes with different applies pressure.