Design of a multi-channel high precision wearable temperature collection system based on negative temperature coefficient thermistor

Jie Tao, Julaiti Maitirouzi Maitirouzi, Huiqing Luo, Tusheng Guo, Ping Wang, Hangning Ren

Article ID: 1621
Vol 3, Issue 2, 2022
DOI: https://doi.org/10.54517/wt.v3i2.1621
VIEWS - 300 (Abstract)

Abstract

Body temperature is often used to screen infectious diseases and monitor treatment. Through the method of measuring the resistance of constant voltage temperature measuring circuit, a wearable multi-point body temperature monitoring system is researched and designed to determine skin surface temperature. The STM32F103C8T6 chip is used as the core processor, and the negative temperature coefficient thermistor (NTC) as the temperature sensing component. ADS1256 chip is a temperature signal conditioner, Bluetooth module is a wireless transmission unit, and LABVIEW is used to design the host computer interface. The constant voltage bridge circuit composed of thermistor and resistor voltage divider to carry out the acquisition of 8 channels of temperature data, and the 24bits ultra-high-precision analog-to-digital conversion module is configured with differential inputs to amplify, filter and convert analog signals; the converted data is processed and calculated in the single-chip microcomputer; finally, the data is transmitted to the host computer via Bluetooth. The thermistor is linearly compensated using the fourth-order formulation of the Stein-hart formula. Reduce the impact of environmental interference and uneven body temperature distribution from software and hardware. The error during the temperature measurement of temperature sensor is analyzed. The experimental results showed that the resolution of measurement system reached 0. 01 , and the temperature measurement accuracy was up to ± 0. 02 . This design scheme has high stability and accuracy; and the circuit is simple in structure, small in size, and low power consumption which can be used in occasions requiring precise body temperature measurement.


Keywords

8 channels body temperature measurement, negative temperature coefficient thermistor, high precision, wearable

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