Research Of Wearable Electronic Thermometer And Its Software & Hardware Design

On the one hand the demand of real-time monitoring of temperature is increasing in home health care field and medical field; on the other hand wireless communications, processing technology and materials technology continue to progress, all these provide good conditions for the development of wearable devices. Based on the above background, this thesis presents the subject of research of wearable electronic thermometer and its software & hardware design.In the study of body temperature sensors, this thesis introduced the design principles of the temperature sensor based on Complementary Metal-Oxide-Semiconductor process, and gave a detailed analysis of the temperature measurement error caused by the saturation current Is, the current gain β and bias current in the design process, then a single-point calibration method was carried out to improve the measurement accuracy of the temperature sensor. And then the performance test experiment of the temperature sensor was designed and completed in climate chamber from -40℃ to 120℃. The test results show that the inaccuracy (+3δ) of the temperature sensor for the body temperature range of 20℃ to 50℃ is within ±0.1℃ and meet the accuracy requirements of clinical electronic thermometer.In the section of the design and test of the wearable body temperature measuring system, this thesis introduced the hardware and software design of the NTC-based temperature sensor terminal, wireless receiver terminal and programming testing board. A method of assembling the wearable temperature sensor terminal was proposed. And then the author gave an analysis of the measurement error of the NTC-based temperature sensor and introduced a method of batch calibration. This thesis proposed a variety of techniques and methods to improve the performance of the temperature sensor and the whole system so as to reduce the size, weight and power consumption of the temperature sensor terminal and enhanced its portability and wearability. The measurement accuracy and power consumption of the whole temperature measurement system was tested, the results show that the temperature error is less than ± 0.04℃ at 37℃, and that the temperature error is less than±0.1℃ from 30℃ to 45℃. The results also show that a button cell with a capacity of 70 mAh can maintain the temperature sensor more than 20 days, and standby the temperature sensor about two years.