Design of an Embedded System for photoplethysmography with a Real-Time Optical Sensor

Design of an Embedded System for photoplethysmography with a Real-Time Optical Sensor

The monitoring of heart rate by using photoplethysmography (PPG) technique is receiving considerable attention. Nowadays as it can solve the problem of monitoring, the heart rate cost effectively and efficiently. Therefore, a real-time optical sensor based on this technique was chosen for reflectance PPG in order to obtain the heart rate of a person from the changes in the blood flow within the arteries. This PPG technique is a non-invasive method both obtaining information about blood volume and monitoring heart rate, whereby it calculates the blood pulse by receiving a reflected light based signal from the blood through a photo detector. The overall system is divided into three modules which are Analogue Front-End for detecting the signal, Embedded System used for sampling the data as well as controlling the brightness of the LED and producing a properly filtered PPG signal by the Graphical User Interface stage. The main scope of this paper is to design an Embedded system which includes controlling the modulation of the light source of LED, sampling the optical signal obtained from the blood via an Analogue-to-Digital Converter, and then transmitting the data to the Graphical User Interface through the RS232 port.