No abstract

The monitoring heart rate by vibration sensor based on self-mixing interferometry (SMI) had been done. Experimental schemes and the performance of vibration sensor based on SMI as a function of frequency and amplitude of human heart rate signals had been examined. The vibration sensor consists of a laser diode as a light source (λ = 785 nm) with integrated detector, a mirror as a vibrating target, and a simulated heart signal from ECG generator. ECG generator signals and audio amplifier are adjusted in frequencies of 1-100 kHz. The result showed that the feedback parameter of SMI signal could be identified at frequency 50 Hz. The heart signal was shown clearly at frequency 100 kHz.

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.