• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.260-265
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• 2011

The silicon vertical hall devices are fabricated using a modified bipolar process. It consists of the thin p-layer at Si-$SiO_2$, interface and n-epi layer without $n^+$buried layer to improve the sensitivity and influence of interface effects. Experimental samples are a sensor type I with and type H without p+isolation dam adjacent to the center current electrode. The experimental results for both type show a more high current-related sensitivity than the former's vertical hall devices. The sensitivity of type H and type I are about 150 V/AT and 340 V/AT, respectively. This sensor's behavior can be explained by the similar J-FET model.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.59.4-59
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• 2001

In this paper, wireless interface of the motion between human and robot is implemented. The idea is that if a human who is equiped with device including accelerometer and rate-gyro sensor move his/her arm, then the robot follows human motion. The robot is designed as wheeled type mobile robot with two link arms. The robot´s basic movements such as forward, backward, left, right movement can be controlled from foot sensor which human steps on. Arm movements can be controlled by arm motion of human motion. In order to detect human motion, sensor data analysis from gyro and accelerometer has to be done. Data from sensors are transferred through wireless communication to activate the robot.

• Journal of Sensor Science and Technology
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• v.18 no.1
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• pp.95-101
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• 2009

A simple and new CMOS potentiostat circuit for amperometric sensor is described. To maintain a constant potential between the reference and working electrodes, only one differential difference amplifier (DDA) is needed in proposed design, while conventional potentiosatat requires at least 2 operational amplifiers and 2 resistors, or more than 3 operational amplifiers and 4 resistors for low voltage CMOS integrated potentiostat. The DDA with rail-to-rail design not only enables the full range operation to supply voltage but also provides simple potentiostat system with small hardwares and low power consumption.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1311-1313
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• 1997

We describe the working principle, the design, and the characteristics of two-chip integrated humidity sensor. The sensing element was manufactured using polyimide. The interface circuits were developed based on a charge redistribution between capacitors. The sensor and signal conditioning chips were packaged together in the same package. The sensor showed excellent linearity over a wide range of relative humidity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.397-400
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• 2007

Indoor air-conditioning system(IAS) using wireless sensor network serves to reduce the amount of pollution entering the room from outside and also the pollution that is generated indoor. Small-size and lower power wireless sensor node and sensor interface board was designed for indoor air-conditioning system in buildings of offices and industrial establishments. Many sensor nodes forms Ad-hoc network topology using simple forwarding routing to transmit polluting gas concentration data from different rooms to the indoor air-conditioning system. Sensor node analyzes pollution concentration in the each room and air-conditioning system performs to air-distribution and air-inhalation according to room's pollution by regulating the fan of indoor air-conditioning system. To reduce power consumption electrochemical gas sensor was used in the design. Thus the designed system can optimize state of indoor environment. Graphic user interface displays node sate, gas concentration and temperature of each room.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.230-237
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• 2010

In sensor signal conditioning and processing, offset and drift characteristics of an operational amplifier are an important factor when the amplifier is used for a precise sensor signal amplifier. In order to use it in high accuracy, an expensive trimming or a complex compensation circuit is required. This paper presents the improved sensor signal conditioning and processing device for ubiquitous sensor network(USN) application or general purpose by developing a hardware of the circuit for reducing the offset voltage and drift characteristics, and a software for its control and sensor signal processing. We realize better offset voltage and drift characteristics of the signal conditioning circuit using low cost operational amplifiers. The experimental results show that this technique is effective in improving the performance of the sensor signal processing device.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.444-449
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• 1998

A modal transducer in two-dimensional structure can be implemented by varying the distributed transducer's gain spatially. In this paper, a method based on finite element method is developed for optimizing spatial gain distribution of PVDF transducer to create the modal transducer for specific modes. Using this concept, one can design the modal transducer in two-dimensional structure having arbitrary geometry and boundary conditions. As a practical means for implementing this continuous gain distribution without repoling die PVDF film, the gain distribution is approximated by optimizing gain-weights of interface circuit. The whole spatial area of the PVDF film is divided into several electrode segments and the signals from each segment are properly weighted and summed by interface circuit. This corresponds to the approximation of a continuous function using discrete values. The electrode partition is optimized using the genetic algorithm. Gain-weights are optimized using the simplex search method. A modal sensor for first to fourth modes of aluminum plate is designed using PVDF film with gain-weighted interface circuit. Various lamination angles of PVDF film are taken into consideration to utilize the anisotropy of the PVDF film. Performance of the optimized' PVDF sensor is demonstrated by numerical simulations..

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.335-340
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• 2011

In the study, a tangible interface using iPhone is proposed to control a mobile robot, instead of remote control by a joystick or buttons. The robot is controlled by iPhone like a handle bar, since acceleration sensors of iPhone are used in the proposed method. The sensors measure the angles changed on the xyz coordinates of iPhone. And their sensor values are stabilized by digital filters. Bluetooth is chosen for communication between a mobile robot and iPhone. In this paper, four type methods are considered and one of the methods is selected for remote control of a mobile robot. Experimental results show that the robot is easily and conveniently controled by the tangible interface based on iPhone.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2205-2210
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• 2015

Experimental studies have been carried out to study the principle operation of the conductive type wire-mesh tomography sensor and analyse the wire-mesh tomography sensor for the liquid/gas two-phase flow interface and void fraction distribution in a process column. The measurement of the two-phase flows in the process column is based on the cross-sectional local instantaneous conductivity. The sensor consists of two planes of parallel electrode wires with 16 electrodes each and was placed orthogonally with each plane. The sensor electrode wires were made of tinned copper wire with an outer diameter of 0.91 mm which stretched over the sensor fixture. Therefore, this result in the mesh grid size with 5.53×5.53mm². The wire-mesh sensor was tested in a horizontal liquid/gas two-phase flows process column with nominal diameter of 95.6 mm and the sampling frequency of 5882.3529 Hz. The tomogram results show that the wire-mesh tomography provides significant results to represent the void fraction distribution in the process column and estimation error was found in the liquid/gas interface level

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1268-1271
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• 2005

This paper proposes a compact-sized surface myoelectric sensor for myoelectric hand prosthesis. To fit the surface myoelectric sensor in the socket of the myoelectric hand prosthesis, the sensor should be a compact size. The surface myoelectric sensor is composed of a skin interface and a single processing circuit that are mounted on a single package. Since the skin interface has one reference and two input electrodes, and the reference electrode is located in middle of two input electrodes, we propose two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material used for the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering conduction velocity and median frequency of the myoelectric signal, we select the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22 mm. The signal processing circuit consists of a differential amplifier with band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value circuit. We evaluate the proposed sensor from the output characteristics according to the IED and the shape of the reference electrode. From the experimental results we show the surface myoelectric sensor with the 18mm IED and the bar-shaped reference electrode is suitable for the myoelectric hand prosthesis.