Thesis
Photoplethysmography (PPG) system
Geert Langereis, Version 2, February 2010
1
Introduction ........................................................................................................................ 2
1.1 1.2 Background on photoplethysmography (PPG) ...................................................................... 2 Specifications of the PPG implementation in this report ....................................................... 2 The optoelectronic parts ......................................................................................................... 4 The electronic circuit ............................................................................................................. 4 Arduino code: Analog “oscilloscope” mode .......................................................................... 8 Arduino code: Digital timing interval mode .......................................................................... 8 Postprocessing of interval data .............................................................................................. 9 Heart-rate in the time domain (1): the asynchronous signal ................................................ 11 Heart-rate in the time domain (2): key characteristics ......................................................... 12 Heart-rate in the frequency domain ..................................................................................... 14 Cross correlation in time and frequency .............................................................................. 14 HRV standards ..................................................................................................................... 14 Hardware .............................................................................................................................. 16 Arduino Code ....................................................................................................................... 16
Geert Langereis, Version 2, February 2010
1
Introduction ........................................................................................................................ 2
1.1 1.2 Background on photoplethysmography (PPG) ...................................................................... 2 Specifications of the PPG implementation in this report ....................................................... 2 The optoelectronic parts ......................................................................................................... 4 The electronic circuit ............................................................................................................. 4 Arduino code: Analog “oscilloscope” mode .......................................................................... 8 Arduino code: Digital timing interval mode .......................................................................... 8 Postprocessing of interval data .............................................................................................. 9 Heart-rate in the time domain (1): the asynchronous signal ................................................ 11 Heart-rate in the time domain (2): key characteristics ......................................................... 12 Heart-rate in the frequency domain ..................................................................................... 14 Cross correlation in time and frequency .............................................................................. 14 HRV standards ..................................................................................................................... 14 Hardware .............................................................................................................................. 16 Arduino Code ....................................................................................................................... 16