• Journal of Sensor Science and Technology
• /
• v.14 no.1
• /
• pp.28-32
• /
• 2005

In this paper, a CMOS integrated detection circuit for capacitive type fingerprint sensor signal processing is described. We designed a detection circuit of charge-sharing sensing scheme. The proposed detection circuit increases the voltage difference between a ridge and valley. The test chip is composed of $160{\times}192$ array sensing cells (12 by $12.7{\;}mm^{2}$). The chip was fabricated on a 0.35 m standard CMOS process. Measured difference voltage between a ridge and valley was 0.95 V.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.987-992
• /
• 2000

In a high speed spindle system, it is very important to monitor the operation of the spindle to prevent catastrophic damage to the system. Widely used sensors for monitoring are eddy-current and capacitive types. These sensors provide high accuracy of monitoring, but their steep prices lead to expensive high speed spindle systems. The main goal of our research is to develop technology for producing high speed spindle system utilizing magnetic bearings. As active magnetic bearings require position sensors for feedback control, a noncontact position sensor is being developed as a part of this main goal. Once developed, it will contribute to affordable high speed spindle system. This paper describes the selection process of the sensor types and the design of the driving circuit. We also report the experimental results that characterize the static and dynamic performances of the inductive sensor.

• Journal of Sensor Science and Technology
• /
• v.19 no.2
• /
• pp.92-98
• /
• 2010

The capacitive sensor has a simple structure, compact size and low cost, but a small dynamic range. The small range is caused by use of gap variation. If the sensor takes area variation type with one plate moving horizontally, it can have a large measurable range. While the area variation has relatively low sensitivity, some studies have found methods to improve the sensitivity. Even though the methods are effective, parameters of the results are limited and 2 dimensional. This study provides more practical and 3 dimensional analysis and suggests relations between parameters. Using the results, the optimized design parameters of a high dynamic range capacitive sensor can be found.

• Journal of Sensor Science and Technology
• /
• v.23 no.1
• /
• pp.24-28
• /
• 2014

A lock-in amplifier was proposed for capacitive sensor applications. This amplifier was based on a general-purpose microcontroller and had only a charge amplifier as analog circuits. All the other functions of lock-in amplifier except for the charge amplifier were implemented with firmware and the internal resources of the microcontroller. A rectangular signal, generated by the microcontroller, was used in a sensor-driving signal instead of a conventional sinusoidal signal. This makes it possible that the phase comparison circuit in the lockin amplifier is made with analog-to-digital converter, a timer and an interrupt controller. Using the oversampling method and the rectangular driving signal, we can make it easy to implement the peak detection function with software and sample the peak-to-peak signal at charge amplifier output. A charge amplifier was proposed to cancel out the base capacitance existing in capacitive sensors structurally. The experimental results show that the lock-in amplifier operating in the supply voltage of 3.0 V cancels out the base capacitance and has good linearity.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.32-37
• /
• 2000

In a high speed spindle system, it is very important to monitor the operation of the spindle to prevent catastrophic damage to the system. Widely used sensors for monitoring are eddy-current and capacitive types. These sensors provide high accuracy of monitoring, but their steep prices lead to expensive high speed spindle system. The main god of our research is to develop technology to produce high speed spindle system utilizing magnetic bearings. As active magnetic bearings require position sensors for feedback control, a noncontact position sensor is bang developed as a part of this main goal. Once developed, it will contribute to affordable high speed spindle system. In this paper, we report the selection process of the sensor types and the experimental results with driving circuits.

• Journal of Sensor Science and Technology
• /
• v.14 no.4
• /
• pp.219-224
• /
• 2005

In this paper, a contact-type linear encoder-like capacitive displacement sensor (CLECDS) is proposed. It is based on the linear encoder capacitive displacement sensor that consists of two substrates with a series of conducting grating in identical size and it is used as a contact sensor of which the two substrates assembled faced to each other after coated with thin dielectric film. It was confirmed that the prototype of this sensor has resolution of about 126nm and measuring range of 20 mm in the test.

• Journal of Sensor Science and Technology
• /
• v.14 no.4
• /
• pp.265-271
• /
• 2005

In this study, a variable capacitive pressure sensor is fabricated for TPMS (Tire Pressure Monitoring System). This study is for developing sensors which consecutively measure the tire pressure given as 30 psi from the industrial standard. For improving non-linearity of the prior capacitive pressure sensors, it is suggested that touch mode capacitive pressure sensor be applied. In addition, initial capacitance is designed as small as possible for the conformity to the wireless sensor. ANSYS, commercial FEA package, is used for designing and simulating the sensor. The device is progressed by MEMS (Micro Electro Mechanical Systems) fabrication and packaged with PDMS. The result is obtained sensitivity, 1 pF/psi, through a pressure test. The simulation result is discrepant from experiment one. Wafer's uniformity is presumed as the main reason of discrepancy.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2001.11a
• /
• pp.211-215
• /
• 2001

실내나 의복내 열적쾌적성을 평가하기 위해서는 정밀하고, 안정성이 높으며 빠른 응답특성을 갖는 센서와 측정시스템이 필요하다. 더욱이 의복내의 온도를 측정하기 위해서는 소형, 경량으로 인체에 부착하기 쉬워야하며 측정기의 부착이 피험자에게 부담을 주어서는 안된다. 본 연구에서는 이러한 요구사항을 만족할 수 있으면서도 이동이 자유롭고 장시간 측정이 가능한 큰 Data 저장용량, 실시간 측정 기능, 손쉬운 온습도 변환장치등을 갖춘 의복내 및 실내 온습도 측정등의 다양한 분야에 활용이 가능한 온습도 측정기와 이에 필요한 센서를 개발하고 개발된 측정기의 선형특성을 평가하였다.

• Annual Conference of KIPS
• /
• 2008.05a
• /
• pp.386-389
• /
• 2008

낮은 처리속도와 기억용량을 가진 임베디드 센서 네트워크의 소프트웨어를 개발할 때 Tiny OS는 컴포넌트방식의 nesC 언어를 이용하여 효율적인 설계를 돕는다. 컴포넌트 방식을 이용하기 때문에 여러가지 소프트웨어의 개발에 자주 사용되는 자산을 분리하여 관리한다면 개발시간과 비용을 절감할 수 있다. 본 논문에서는 Tiny OS 기반에서 임베디드 센서 네트워크 소프트웨어 개발 시 프로덕트라인 방법을 적용하여 공통적인 자산과 가변적인 자산을 구별하고 재사용성을 높이며 개발 효율을 증대하는 방안을 제시한다. 이러한 연구는 이종의 임베디드 소프트웨어 개발에도 적용되어 늘어나는 임베디드 소프트웨어의 양적, 질적 수요를 충족시켜주는데 도움이 될 것이다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.6
• /
• pp.183-188
• /
• 2014

With the rapid growth of the mobile computing and sensor technologies, various application techniques related to USN converged with other related technologies are actively disseminated recently. Most of these applications are aimed at the proper control and system monitoring using context information gathered through various sensors. But it is not easy to control and monitor the system precisely and flexibly since data generated by sensors are huge and variety. In this paper, we design and implement the fuzzy-logic based central control system in USN to provide the flexibility and preciseness with sensed data. The performance of the proposed system is evaluated by a simulation study in terms of consumed electric power on the test bed of USN based streetlight control system.