Heart rate monitoring by using non-invasive wearable sensor

This paper presents a wearable system for heart rate monitoring based on photoplethysmography (PPG). This method based on sensing the cardiovascular pulse presents the analyzing of the light variations on biological tissues. The interaction of light with biological tissue is a complex phenomenon, therefore, involves scattering, absorption and reflection. In our work, we used for PPG the reflectance mode. Blood absorbs more light than others tissues and the reduction of the blood amount shows an increased intensity of the light scattered back of reflected from tissue. This approach is very comfortable for patients because the light sensor it is integrated into garment. This method can be useful for wireless patient monitoring consequently ambient assisted living applications if is completed with others aggregators (smartphone, notebook). For hearth rate monitoring are used contact sensors and non-contact remote measurement (Doppler radar technology). The non-contact and remote measurement has the disadvantage of mobility limitation (this method can be used in laboratory or in hospitals). The contact non-invasive sensing method for hearth rate monitoring has the advantage to be wear by the user.