Analysis of Source-to-Area Distance in PPG Signal Detection Using Phototransistor

Abstract:

Photoplethysmography utilizes a light source and a light sensor in order to receive a signal corresponding to particular information one wants to convey. The distance of the source to the area of the signal to be measured is very essential to be able to get the best probable signal. The aim of this study is to determine the best possible distance of the light source to the area to be measured that would give optimum detection response. This study was composed of two parts which both employed Backscatter simulation to compare the different distances of LED to the area to be measured. Both parts also utilized phototransistor as the light sensor. In the first part, white, green, red, orange, blue and yellow light emitting diodes were used as light sources whose distances were varied from 5 to 10 cm. The distance and three LED colors with the best PPG signals detection obtained from the first part were the distance and LED light sources used in the second part. The second part included distances of 1, 3 and 5 cm of the LED to the area to be measured, particularly the dorsal skin of human subjects. The series of experiments conducted proved that orange LED was the best emitter source for simple detection; however, for applications involving human skin, the yellow LED was the best source to be used at a distance of 3 cm away from the area to be measured.

Año de publicación:

2020

Keywords:

• backscatter simulation
• photoplethysmography
• optical response
• Distance
• phototransistor

Fuente:

scopus