Improvement of photo-electric plethysmograph applying newly developed opto-electronic devices

Photo-electric plethysmograph has been widely used to measure the cardiac pulse rate. However, the sensing device remains without any improvement, even though the opto-electronic technology has been highly refined recently. In order to get rid of low-temperature burn, which is often experienced in long-term, continuous applications, and to guarantee enough motion-free measurements, we develop a new type of photo-electric sensing device, together with more sophisticated signal processing circuits. The design criteria and the merit of the prototype device are discussed in some detail.