Four channel device for PPG measurements

The article deals with the design of four channel device serving for photoplethysmographic measurements. There are described main parts of the device such as analog and digital signal processing part and microcontroller controlled LED drivers. The work includes description of digital data processing algorithm. There is presented design of graphical user interface and device functionality verification. The use of the device for medical purposes is outlined too. Preliminary measurements and data analysis were performed. Within the analysis we correlated second derivative of pulse wave contour with age of measured subjects.