Design and Fabrication of Embedded Wireless Monitoring System Based on Bluetooth Low Energy Transmission for Potentiometric Sensors
Zhong Cao, Wenfeng Li, Chen Liu, Yu-Yu Peng, Ying J. Huang, Zhongliang Xiao · CHINESE JOURNAL OF ANALYTICAL CHEMISTRY (CHINESE VERSION) · 2021
A small embedded wireless monitoring system for potentiometric sensors was designed and fabricated. The system employed a dual precision op amp of TLC4502 as the preamplifier and a bluetooth low energy (BLE) chip of CC2541 as the main controller, and the main controller integrated 14 bits analog to digital convertor (ADC). The system used the BLE development application program (App) to establish a Bluetooth connection with the CC2541 for wireless real-time reading of sensing potentials. The monitoring system software was developed on the basis of a BLE-CC254X-1.41 protocol stack by the embedded development software of IAR Embedded Workbench. To verify the reliability and accuracy of the system, a precision regulated power supply was used for analog potential acquisition test, and a pH composite electrode was used for monitoring the pH change. The test results showed that the system could be applied to real time measurement of potential signals for three times amplification with an accuracy of 0.4 mV, and a consistent response to pH change was able to quickly output with a linear correlation coefficient of R2=0.9994. Furthermore, the concentration change of L-cysteine (L-cys) was monitored in real time by the BLE system with a self-made L-cys sensor, and the dynamic response change was consistent with that of commercial multimeter, indicating that the rapid transmission and real time monitoring of potentiometric signals could be well realized through the BLE wireless sensing system.