Development of Home-care System Using RF Transceiver and Internet

• Main Authors: Chin-Yuan Tu, 涂清源
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/22170200305413342083

碩士 === 中原大學 === 醫學工程研究所 === 90 === Due to the increase of aging population in Taiwan, taking care of elderly will become a social problem we will face in the coming century. The routine medical checkups not only cause weariness for elderly to make the trip but also cannot provide real-time consultation and medical assessment. Thus, a home-care system is proposed to provide monitoring service in order to take full advantage of existing medical resource. In this study, the proposed system consists of signal acquisition, radio frequency (RF) transmission, signal processing, internet communication and database modules. The ECG signal is amplified and filtered in the signal acquisition module. The total gain of ECG amplifier is 570 and the filter bandwidth is from 0.5 to 100 Hz. The RF transmission module is consist of MSP430F148 micro-controller and TRF6900 RF transceiver. The bio-signal is digitized by the built-in analog-to-digital converter (ADC) in the micro-controller and organized into a data package. As soon as the package is established, it is sent by the transceiver using the high-frequency band. On the receiver side, it utilizes the same communication protocol to extract signals from the received package. Data is then passed to the personal computer (PC) through the RS232 interface, on the receiving side, for signal processing, analysis and storage. In addition to waveforms display, the PC processes the acquired signals and obtains biological parameters such as heart rate for evaluating user’s physical condition. At the same time, the application program on the PC can establish internet connection with the remote server in the hospital. After processing, data is saved in the Access database for long-term physical condition monitoring. The results indicate that the effective range of the RF transmission module is 7 meters with accuracy of 100%. In this range, the package missing rate is 6.83% and the transmission rate is 38400bps. This demonstrates that the RF module can provide reliable real-time transmission. However, it is found that the length of training sequence during package transmission is inverse proportional to signal sampling rate and package missing rate. The shorter the training sequence is the higher the package missing rate is. The trade-off between package missing rate and sampling rate can be resolved by external ADC in the future. The results of internet transmission evaluation indicate that the transmission rate is 0.5 kbps with 98.99% accuracy which is satisfactory for a reliable internet transmission. However, the transmission rate is too low for real-time purpose. Thus, it is necessary to increase the transmission rate in the future.