Health Monitoring System in the Bedroom using Ubiquitous Technology

Advances in information technology have enabled ubiquitous health monitoring at home, which is particularly useful for patients, who have to live alone. We have focused on the automatic and unobtrusive measurement of biomedical signals and activities of patients. We have constructed wireless communication networks in order to transfer data. The networks consist of Bluetooth and Wireless Local Area Network (WLAN). In this paper, we present the concept of a ubiquitous-Bedroom (u-Bedroom) which is a part of a ubiquitous-House (u-House) and we present our systems for ubiquitous health monitoring. INTRODUCTION Ubiquitous health monitoring allows biomedical signals to be measured without the individual’s awareness. For successful ubiquitous monitoring the biomedical signals need to be measured unobtrusively and the data need to be transferred using a wireless communication system. Biomedical signal measurement is very important in the field of telemedicine and health monitoring because it is the precursor of analysis and diagnosis. In previous studies unobtrusive biomedical signal measurement was not a main issue. M. Ishijima[1] presented a method to measure Electrocardiogram (ECG) in bed without any body surface electrodes. Instead of body surface electrodes, conductive textile electrodes were used in order to measure ECG signal. T. Tamura et al.[2] showed that it was possible to obtain ECG signal in the bathtub only using water. Bluetooth communication technology has many advantages for the field of telemedicine. A lot of data has to be transferred and processed because biomedical signals, activities and environmental parameters are always being monitored. Wireless Local Area Network (WLAN) is needed in association with Bluetooth communication network. Using Bluetooth technology and WLAN, any problems regarding bandwidth and speed can be solved. In this paper, we describe ubiquitous health monitoring system in the bedroom. We have focused on the unobtrusive biomedical signal measurement and wireless data transfer using Bluetooth technology and WLAN. These two main technologies have enabled ubiquitous health monitoring without patient’s awareness. MATERIALS AND METHODS The ubiquitous-House (u-House) has a toilet, kitchen, living room, and three bedrooms. Sensors are installed in each location. In the bedroom, there are five sensors which measure biomedical signals, activities and environmental parameters. Fig. 1 Diagram of the ubiquitous bedroom and location of sensors A. Unobtrusive Biomedical Signal Measurement In the bedroom, three biomedical signals can be measured from the bed. 1) ECG signal measurement on bed An ECG signal can be obtained from the patient in bed using a conductive sheet. Whenever the patient lies on bed at night, ECG signals are measured by a conductive textile electrode attached to the bed sheet. In order to process the ECG signal an amplifier has been developed. This bioamplifier has several filters, namely a low-pass, notch, and high-pass filter. Such filters can remove noise and it is possible to obtain a clear ECG signal comparable to the common Ag-AgCl direct contact electrode. 2) Body movement during sleep Bed Loadcell Conductive Sheet Snoring Sensor Magnetic Switch Temperature Sensor Door