Design of a Low-Frequency Microphone for Mobile Phones and Its Application to Ubiquitous Medical and Healthcare Monitoring

This paper describes a novel strategy for providing ubiquitous medical and healthcare monitoring through the use of a mobile phone equipped with a low-frequency microphone sensitive to pressure waves in the frequency range of 0.1 Hz to 10 kHz. The mobile phone is placed in a sealed air cushion under the pillow or mattress of the subject's bed. The low-frequency microphone in the mobile phone picks up the signals from the subject's heartbeat, respiration, body movement and snoring and transmits them to a healthcare center where an auto-diagnosing system or specialist monitors the subject's health condition. By simply replacing the conventional audio-microphone with the low-frequency microphone, novel ubiquitous medical and healthcare functions are added to mobile phones. The low-frequency microphone as a key device was newly designed and its validity was examined by experiment.