Heart rate measurement from fingertips / Muhamad Amirul Mohd Jamaluddin & Abdul Auf Rahman

The heart rate is one of the significant physiological parameters of the human cardiovascular system. Heart rate is the number of times the heart beats per minute. Heart rate data reflects various physiological states such as biological workload, stress at work and concentration on tasks, and the active state of the nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sympathetic regulation increases and parasympathetic regulation decreases the heart rate. Thus, monitoring of heart rate plays a significant role in providing the status of cardiovascular system and clinically related information to medical professionals. Heart rate measurement is also considered as an essential parameter in patient care monitoring system. Heart rate can be measured either by the ECG waveform or by sensing the pulse - the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of the heart. The pulse can be felt from those areas where the artery is close to the skin. This paper highlights on the design of a microcontroller (PIC series) based heart rate counter that is able to capture the pulse from fingertip by sensing the change in blood volume. Heart rate of the subject is measured from the finger using optical sensors to detect the flow of blood through the finger. The main analog signal received from the human body gets captured with an instrumentation amplifier MC1458. Then the signal is filtered with another Op-Amp. The pulses are counted by a microcontroller and the output of the circuit is displayed on the seven segment clearly. This project design provides fastness and safety. Moreover, the installation of this device is not easy. Also, the designed device, being noninvasive one, can easily find its place in health care monitoring system.