由於無線感測網路所提供的方便性，無線感測網路已漸漸被廣泛應用在環境監測、工業運用、健康照護以及居家應用等等，不同種類的感測器和無線感測平台也隨之發展。面對琳瑯滿目的感測器，如何設計出一個對於使用者來說最合適的無線感測器介面平台，成了設計無線感測平台的一個重點。
　　一般說來，無線感測器介面的功能為在固定的頻率下取樣感測器輸出的感測資料並將此資料轉成微處理器可處理的資料格式。它會影響到整個無線感測平台的消耗功率、資料精準度、以及取樣頻率等等。
　　目前市面上感測器輸出格式可分為類比輸出、數位輸出、電容量輸出以及高階協定輸出。在本論文中，我們提供了類比輸出以及數位輸出的無線感測器介面平台架構；並將元件特性參數化，經由實驗整理出這些參數和應用需求及傳輸效能的關係式，藉此關係式可得知對應用最佳化的元件所需特性。我們更提供了一些簡單測試無線感測平台性能的方法還有一套依據應用需求的偏好程度來計算整體效益的公式，使用者可以藉此得到無線感測平台的效能。
　　實驗中，我們從上述的方法實際設計了類比輸出以及數位輸出的無線感測器介面，並利用數位訊號處理來達到應用需求的精準度和高取樣頻率。
　　我們希望這些方法能幫助設計者更有效且更迅速地設計無線感測介面平台，也幫助設計者或使用者從而選擇最適宜的無線感測平台。

Wireless sensor networks are being considered in a wide range of applications, from environmental monitoring and industrial monitoring to health care management and home use. Different sensing devices and sensor platforms have been developed to date. One of the most important design problems is how to design an interface for a wireless sensor platform. The interface between the microcontroller and the sensing devices directly affect the performance, power usage, and data accuracy of a sensor platform.
In this thesis, we categorize the sensing devices and propose a methodology for systematic selection of the interface for cross-layer optimization. Sensing devices are categorized based on their output type, including analog, digital, capacitive, and high-level protocol types. We derive formulas for evaluation and estimation of sensor platforms implemented with alternative choices of interfaces. We demonstrate this methodology with case studies of a real-world sensing platform by comparing analog and digital alternatives of sensing devices. We also use digital signal post-processing as a case study for evaluating the accuracy and high sampling rate as required by the application.

[1] C. Park and P. H. Chou, "EmPro: an environment/energy emulation and profiling platform for wireless sensor networks," in Proc. 3rd Annual IEEE Communications
Society on Sensor and Ad Hoc Communications and Networks(SECON), vol. 1, Sep.2006, pp. 158-167.
[2] C. Xiao, L. Zhao, T. Asada, W. G. Odendaal, and J. van Wyk, "An overview of inte-gratable current sensor technologies," in Industry Applications Conference, Oct. 2003.
[3] Http://www.sensorland.com/HowPage018.html.
[4] F. M. L. Van Der and G. C. M. Meijer, "A universal transducer interface for capacitive and resistive sensor elements," Analog Integrated Circuits and Signal Processing, vol. 14, pp. 249-260, 1997.
[5] X. Li, G. C. Meijer, R. de Boer, and M. van der Lee, "A high-performance universal sensor interface," in Sicon'01 Sensor for Industry Conference, Nov. 2001.
[6] G. Chao, L. Xiujun, and G. C. Meijer, "A system-level approach for design of smart sensor interfaces," in Proc. Conference of IEEE Sensors, 2004.
[7] K. L. Kraver, M. R. Guthausa, T. D. Stronga, P. L. Birda, G. S. Chab, W. Holdc, and R. B. Browna, "A mixed-signal sensor interface microinstrument," Proc. of the
International Solid-State Sensors and Actuators Conference, vol. 91, pp. 266-277, Jul. 2001.
[8] D. Potter, "Overview and application of the IEEE P1451.4 smart sensor interface standard," in Proc. IEEE AUTOTESTCON, 2002.
[9] B. Schott, M. Bajura, J. Czarnaski, J. Flidr, T. Tho, and L. Wang, "A modular power-aware microsensor with >1000x dynamic power range," in Proc. ACM/IEEE International Conference on Information Processing in Sensor Networks, 2005.
[10] C. Park, J. Liu, and P. H. Chou, "B#: a battery emulator and power-pro‾ling instrument," IEEE Design and Test of Computers, vol. 22, pp. 150{159, Mar-Apr 2005.
[11] F. Simjee and P. H. Chou, "Accurate battery lifetime estimation using high-frequency power profile emulation," in ISLPED, Aug. 2005.
[12] A. Serra, "New measurement procedure for the static test of ADCs," in Proc. 17th IEEE Instrumentation and Measurement Technology Conference, 2000.
[13] S.-C. Huang, "Quantitative evaluation and practical emulation methodologies for wireless sensor platforms," Master's thesis, National Tsing Hua University, 2007.
[14] P. H. Chou and C. Park, "Energy-e±cient platform designs for real-world wireless sensing applications," in Proc. IEEE/ACM International Conference on Computer-aided
Design, 2005.
[15] N. Xu, S. Rangwala, K. K. Chintalapudi, D. Ganesan, A. Broad, R. Govindan, and D. Estrin, "A wireless sensor newtork for structural monitoring," in Proc. 2nd Interna-
tional Conference on Embedded Networked Sensor Systems, Nov. 2004.
[16] C. Park and P. H. Chou, "Eco: Ultra-wearable and expandable wireless sensor platform," in Proc. 3rd International Workshop on Body Sensor Networks, Apr. 2006.
[17] J. Hahn, S.-M. Yoo, Q. Xie, C. Park, and P. H. Chou, Eco v0.1 System Programmers' Manual, May 2006.
[18] Product Specication nRF24E1, Nordic Semiconductor, Mar. 2006.
[19] Model 1221 Low Noise Analog Accelerometer, Silicon Designs, Inc., Sep. 2007.
[20] Triaxial Digital Accelerometer Module:2420, Silicon Designs, Inc., Sep. 2007.
[21] S. Hay‾n and B. Van Veen, Signals and Systems. Wiley, 2006, ch. 8.