• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.103-107
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• 2021

In this paper, a capacitive water level sensor for boilers was developed. In order to accurately monitor the water level in a high-temperature boiler that generates a lot of precipitates, the occurrence of precipitates on the surface of the water level sensor should be small, and a sensor capable of measuring even if the sensor surface is somewhat contaminated is required. The capacitive water level sensor has a structure in which one of the two electrodes is insulated with Teflon coating, and the stainless steel package of the water level sensor is brought into contact with the water tank so that the entire water tank becomes another electrode of the water level sensor. A C-V converter that converts the capacitance change of the capacitive water level sensor into a voltage change was developed and integrated with the water level sensor to minimize noise. The performance of the developed capacitive water level sensor was evaluated through measurement.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.124-128
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• 2019

In this paper, a high temperature plastic film type water level sensor was developed. The high temperature film type water level sensor was manufactured by attaching a copper film to a polyimide film which can be used for a long time at 250℃, by laminating process and patterning the electrode by etching process. For the performance evaluation of the developed film type water level sensor, the temperature dependence of the capacitance was measured, and the deformation was examined after standing for 8 hours in 150℃ air. The developed film type water level sensor can be used at up to 150℃, and can be applied to electric ports and steam devices.

• 센서학회지
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• 제33권5호
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• pp.373-377
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• 2024

To increase the sensitivity of film-type level sensors for water-level measurements, a Wheatstone bridge comprising a half-bridge circuit with a new film-type level sensor design containing four resistors and two electrodes was employed. The proposed film-type level sensor included a temperature compensation feature and demonstrated improved sensitivity owing to a two-fold increase in the voltage output. Furthermore, a repetition error of less than 1.0% was observed for water levels. As the change in resistance varied linearly with the water level, a linear function was derived to represent their relation. Using this derived formula, water level measurements that were twice as precise as those yielded by commercial products were achieved.

• 한국인터넷방송통신학회논문지
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• 제24권4호
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• pp.129-134
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• 2024

본 논문에서는 적외선 센서, 레이저 센서, 초음파 센서, 정전용량 센서로 실험을 통해 수위의 변화를 선형적으로 감지할 수 있는 수위센서를 이용한 액적 토출 시스템을 연구하였다. 전원 공급으로 SMPS, 레귤레이터 5V, LDO 3.3V를 설계하였으며 수위 센서 입력부 ADC 회로와 마이크로프로세서를 이용하였다. 또한 솔레노이트 밸브 제어, 양압/음압 발생을 위한 펌프 출력 제어부와 산업용 통신을 위한 CAN 통신, 이터넷 통신, UART 통신, USB를 사용하였다. 수위의 변화를 통해 압력의 변화를 확인하였으며, 압력의 변화를 최소화하여 액적 토출을 위한 시스템을 구현하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.471-474
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• 2002

A fuel tank contains water at the bottom under the fuel. The water comes from humidity by temperature change of inside and outside of tank. So it is necessary to measure both level to check precise amount of oil. But measuring instrument for level of water and fuel is not available yet. Since the fuel is inflammable, the sensor system must not include any electric circuits in the fuel tank. Optical cable sensor can satisfy this non-explosive condition. The displacement of a float changing by water level makes bending curvature of optical cable different. As the float rise up, the optical cable is bent more and the light signal in the cable decreases. The reduction of light signal is detected and it is converted into the change of water level. The output signal from a photo diode shows the proportional relation of water level. The increase of sensor voltage as a unit of ㎷ follows the level position of the float that is located between water and gasoline in the tank.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.95.1-95
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• 2002

<1. New level meter inside the fuel tank> Ultrasound level sensors are widely applied as level meters of liquid tank. Measurement instrument of level between water and fuel is developed. Since the fuel is inflammable, the sensor system doesn't allow to include any electric circuit inside the fuel tank. The optical cable sensor can satisfy this explosive condition. The measurement method with ultrasonic sensor is attached on the tank wall or tank manhole lid. The pressure sensor can't be applied inside the gasoline fuel tank. An ultra-sonic sensor doesn't detect a enough signal reflected from water level deep under gasoline fuel. The pressure sensor is difficult to measure the height o...

• 센서학회지
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• 제33권5호
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• pp.378-383
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• 2024

This study developed a buoyancy-based level sensor composed of a buoyant object, a sensing unit, and a signal generation unit to meet the demand of low-cost, high-efficiency inundation-detection sensors. The volume of the submerged buoyant object remained nearly constant even in the presence of water-level fluctuations, allowing stable water-level data acquisition. The measurement resolution and measurement repeatability were confirmed to be within 0.4 mm and 0.3%, respectively. LoRa-based communication was used to implement the IoT-based inundation-detection sensor. The measurement deviation between the sensors is approximately 0.15%. The unresponsive level at which measurement was not possible was confirmed to be approximately 2 mm. Excluding this unresponsive range, the water level measurements exhibited very high linearity, allowing precise measurements. Furthermore, a test bed was established in an inundation-vulnerable area using buoyancy-based level sensors.

• 한국인터넷방송통신학회논문지
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• 제18권4호
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• pp.143-147
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• 2018

수위는 하수장, 정수장, 하천, 댐, 공장의 저장탱크 등 다양한 분야에서 측정된다. 수위측정을 위한 초음파 기기가 판매중이나 산업용으로 실험에서 사용하기는 가격이 너무 비싸다. 전자 기술의 급속한 진보로 인해 다양한 종류의 측정, 모니터링 및 제어 기능이 저렴하게 구축하는 것이 가능해졌다. 저렴한 가격으로 초음파 수위 측정시스템을 만들기 위하여 본 연구가 시작되었다. 실험용으로 사용하기 위하여 아두이노, 초음파 센서 및 온도 센서로 시스템을 구성하였다. 초음파 센서는 센서에서 수위 표면까지의 시간을 측정한다. 온도 센서는 대기 온도를 측정하며 온도 변화로 인한 소리의 속도를 보정하여 초음파 거리 측정의 정확성을 높인다. 아두이노는 측정 전반을 관리하고 수위를 계산한다. 시스템의 모든 구성 요소는 장치거치대에 조립되었다. 제안된 시스템을 가지고 실험한 결과 수위가 실측치와 매우 가까웠다. 이 시스템은 또한 저렴하며 설치 및 유지하기가 쉬워 실험용으로 적절하다.

• 한국자기학회지
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• 제21권1호
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• pp.32-36
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• 2011

DC 마그네트론 스퍼터링을 이용하여 제작한 고감도 거대자기저항 스핀밸브 박막 소자를 이용하여 수위 및 수온을 측정할 수 있는 센서를 제작하였다. 제작한 센서의 수위 및 수온 분해능은 각각 $400\;m{\Omega}/mm$와 $100\;m{\Omega}/^{\circ}C$ 이었으며, 이는 전립선 비대증 KTP(potassium titanyl phosphate) 레이저 치료기에서 냉각기의 수위 및 수온을 조절하는 센서로써 응용이 가능하다.

• 농촌계획
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• 제21권4호
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• pp.177-186
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• 2015

The main objective of this study was to assess the applicability of IoT (Internet of Things)-based flood management under climate change by developing intelligent water level monitoring platform based on IoT. In this study, Arduino Uno was selected as the development board, which is an open-source electronic platform. Arduino Uno was designed to connect the ultrasonic sensor, temperature sensor, and data logger shield for implementing IoT. Arduino IDE (Integrated Development Environment) was selected as the Arduino software and used to develop the intelligent algorithm to measure and calibrate the real-time water level automatically. The intelligent water level monitoring platform consists of water level measurement, temperature calibration, data calibration, stage-discharge relationship, and data logger algorithms. Water level measurement and temperature calibration algorithm corrected the bias inherent in the ultrasonic sensor. Data calibration algorithm analyzed and corrected the outliers during the measurement process. The verification of the intelligent water level measurement algorithm was performed by comparing water levels using the tape and ultrasonic sensor, which was generated by measuring water levels at regular intervals up to the maximum level. The statistics of the slope of the regression line and $R^2$ were 1.00 and 0.99, respectively which were considered acceptable. The error was 0.0575 cm. The verification of data calibration algorithm was performed by analyzing water levels containing all error codes in a time series graph. The intelligent platform developed in this study may contribute to the public IoT service, which is applicable to intelligent flood management under climate change.