Portable heart rate detector based on photoplethysmography with android programmable devices

In this paper, a miniature portable heart rate detector system is implemented by modern hardware ICs and simple sensor circuit with software executable on Android platform. The biosignal is first extracted via photoplethysmography (PPG) principle into electric signal. Then a microprocessor is used to covert biosignal from analog to digital format, suitably for feeding into an RF module (nRF24L01 for RF transmission). On the receiver end, the computer and/or smart phone can analyse the data and display the heart rate status for health care monitoring. The housing for portable devices and PCB is tailored made by using the new 3-D printer with ergonomic design. Initial prototype size is 40 × 30 × 20 mm³ and could be smaller in later version. Some application software running on Window application and Android phone have been developed to display result for users. In the future, pure Bluetooth technology will be used for wireless personal communications instead of RF modules. At the same time, the data can be sent to computer console using existing available networks (3G, 4G, WiFi, etc.) for health database logging purpose.