Study on the multi-sensing system based on the wireless communication technology Jui-Fu Cheng1, Jung-Chuan Chou2*, Tai-Ping Sun3, and Shen-Kan Hsiung1 1
2
Institute of Electronic Engineering, Chung Yuan Christian University, Chung-Li, Taiwan 320, R.O.C., Graduate School of Electronic Engineering, National Yunlin University of Science and Technology, Douliou, Taiwan 640, R.O.C., 3 Department of Electrical Engineering, National Chi Nan University, Nantou, Taiwan 545, R.O.C. E-mail:
[email protected]
Abstract—In this investigation, the multi-sensing system based on the wireless communication technology was presented. The multi-sensing system consists of the multi-sensors module, PIC microcontroller module, Bluetooth communication module, and graphic LabVIEW program module. The experimental data can be transferred to the computer by this system without distance limit. The experimental data include pH, pK, pNa, and pCl in the buffer solutions. Keywords: Multi-sensing system, wireless communication technology, PIC microcontroller module, Bluetooth communication module d, LabVIEW. Topic: (10) Sensor systems
applications of multi-sensors detections. Finally, the main goal of this investigation is to combine the technologies of multi-sensors, the wireless communication, and graphic LabVIEW program to realize the multi-sensing system. 2. EXPERIMENTAL 2.1. Multi-sensors module The ion-selective membranes were used to deposit on the SnO2 pH electrode to fabricate the potassium, sodium, and chlorine ion-selective electrodes (ISEs). The multi-sensors module consists of these electrodes and the reference electrode (i.e. Ag/AgCl glass electrode), and were used to detect the concentrations of pH, pK, pNa, and pCl in the buffer solutions. Fig. 1 and Fig. 2 show the cross-sectional view and structure of the multi-sensors, respectively.
1. INTRODUCTION The wireless communication technologies, such as the Home RF, IEEE802.11, IrDA, and Bluetooth, are used extensively in many applications [1, 2]. After comparing these wireless communication technologies, the Bluetooth technology not only has the advantages of low power and low consumption, but also transmits data within 100 meters. Consequently, the Bluetooth technology is very suitable for the applications.
Figure 1. Cross-sectional view of the multi-sensors.
Moreover, according to the previous literatures, the SnO2 pH electrode fabricated by radio frequency sputtering method has the advantages of good sensitivity, easy fabrication, low cost and disposable device for the pH detection [3-5]. The ion electrodes were fabricated by the sputtering method in this study, and the sensing membranes were coated on the surface of those ion electrodes to form the potassium electrodes, the sodium electrodes, and the chlorine electrodes. In addition, Arshak et al. [6] presented a novel humidity sensor with an error-compensated measurement system based on the graphic LabVIEW program. Thus, according to the results, the graphic LabVIEW program is suitable and powerful for the
Figure 2. Structure of the multi-sensing system.
2.2. PIC microcontroller module As shown in Fig. 2, the PIC microcontroller module consists of the front-ended analog readout circuits and the PIC microcontroller [7-9]. As aforementioned descriptions, the designed readout circuits consist of the instrumentation amplifier, high pass filter, gain-stage amplifier, level shift circuit, and the low pass filter [7, 8]. After processing the sensing signals, the measurement results can be transferred to the output (i.e. the Bluetooth communication module).
2.4. Graphic LabVIEW program module While the computer had received the measurement results of the concentrations of the multi-sensors in the buffer solutions, the graphic LabVIEW program module was employed to obtain and analyze the sensing signals, such the concentrations of pH, pK, pNa and pCl. Finally, the measurement results can be shown on the monitor display. Consequently, the multi-sensing system is effective for the multi-sensors detections. 3. RESULTS AND DISCUSSION
2.3. Bluetooth communication module After processing the sensing signals from the PIC microcontroller module, the measurement results can be transferred to the computer with wireless method by the Bluetooth communication module. As aforementioned descriptions, Fig. 3 shows the structure of the Bluetooth communication module.
After obtaining the sensing signals from the buffer solutions by the multi-sensors module, the measurement results can be transferred to the PIC microcontroller module. Finally, Fig. 4 shows the measurement results of the multi-sensors. The sensitivity and linearity of each sensor has good performance. 4. CONCLUSION
PIC microcontroller module
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The multi-sensing system based on the wireless communication technology was presented in this investigation. According to the experimental results, the multi-sensing system was successfully combined with multi-sensors module, PIC microcontroller module, Bluetooth communication module and Graphic LabVIEW program module for detecting pK, pNa and pCl in the buffer solutions.
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Figure 3. Structure of the Bluetooth communication module. K ISE (Sensitivity=52.92mV/decade)
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This study was supported by National Science Council, The Republic of China under the contracts NSC 94-2213-E-033-005. [1]
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Figure 4. Measurement results of the multi-sesnors. (a) pH sensor. (b) potassum sensor. (c) sodium sensor. (d) chlorine sensor.
[7] [8] [9]
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