The aging population and a lack of recourses such as workers, places in Japan become a serious concern. Miniature body sensors can perform long-term and ambulatory health monitoring, such as heart rate and blood pressure monitoring. However, technology, healthcare, and easy user interface have not yet been collaborating deeply and much research is underway. This research uses light sensing to acquire biological information such as SpO2, blood pressure via a non-invasive approach. In this research, a cheap, easy to use, and low power consumption device prototype used to obtain SpO2 related information is designed. The proper light wavelength for light sensing in our device is discussed and related experiments are carried out and the data is analyzed. The experiment and data analyzing results show that the proposed SpO2 evaluation method is useful and practical. In future work, the blood pressure data processing method will be studied.