Preliminary Studies Comparing Heart Rate Measurement Using Optical Sensor Based on Self Mixing Interferometry and Photoplethysmography (PPG)

Heart Rate is important information about the physiological and psychological condition of human. The pulse rate is directly related to the heart activity because of the impact of the volume changing of blood correlated to the heart which pumps blood throughout the body periodically. Heart rate measurement is used generally ECG (Electrocardiogram) or Blood Pressure Measurement in the medical world. In this paper the ratio of the heart rate is analyzed by using a technique photoplethysmography and optical sensor based on self-mixing interferometry. A typical self-mixing configuration consist of a laser diode as a light source (LD, 785 nm) and the photodetector which integrated in the package. Photoplethysmography consist of infrared (IR, 940 nm) acts as source of light, photodiode as a photo-detector, PPG circuit, arduino and PC. Photoplethysmography is non-invasive optical technique that can used to detect blood volume changes in the microvascular bed of tissue. The result show that human heart rate signals can be detected using the SMI method with a frequency of 100 kHz and input current 50 mA, but using PPG method the human heart signal was detected in the amplitude range of 2,070 to 2,080 mV.