Pulse oximetry is the non-invasive measurement of the oxygen saturation (SpO2). It is used for a rapid assessment of a patient's respiratory function to determine onset of hypoxemia (oxygen starvation) or COPD (Chronic obstructive pulmonary disease). The sensing device is worn in the fingertip which makes it the one with least discomfort among the devices for measuring vital parameters. In many critical situations, it is the ideal candidate for continuous monitoring using a wearable system for

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... lert generation. We have developed the prototype of such a device which can be connected to any android based mobile phone. It consists of a hardware subsystem with a very small footprint for continuous acquisition of SpO2 signal for transfer to the mobile phone of the user. A part of the mobile application runs in the background to continuously acquire this signal, convert it into calibrated values of SpO2 and pulse rate and store them in the local DBMS. In case the connection to a Hospital DBMS is enabled, it is updated there as well. The foreground part of the application provides the instantaneous values of pulse rate and SpO2, along with their trends and minimum values. By continuous monitoring of pulse rate and SpO2 in the background, the application can detect the onset of hypoxemia and COPD and can give suitable alarms. The Hospital DBMS can be accessed by the consulting clinicians, thereby allowing remote monitoring of patient health condition. The device is being integrated into a wearable Body Area Network having ECG, Pressure and Temperature sensors for the complete monitoring of all vital parameters. Once clinically accepted, it can become a low cost alternative to the current bedside monitoring system used in hospitals. This paper presents the hardware and software aspects of the SpO2 sensor segment developed.