• Journal of the Semiconductor & Display Technology
• /
• v.20 no.3
• /
• pp.103-107
• /
• 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.

• Journal of the Semiconductor & Display Technology
• /
• v.18 no.4
• /
• pp.124-128
• /
• 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.

• Journal of Sensor Science and Technology
• /
• v.33 no.5
• /
• pp.373-377
• /
• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.24 no.4
• /
• pp.129-134
• /
• 2024

In this paper, This paper is a liquid droplet discharge system using a water level sensor that can linearly detect changes in water level through experiments with an infrared sensor, a laser sensor, an ultrasonic sensor, and a capacitance sensor. SMPS, regulator 5V, and LDO 3.3V were designed for power supply. A water level sensor input ADC circuit and microprocessor were used. Solenoid valve control, pump output control unit for positive/negative pressure generation, CAN, Ethernet, UART communication, and USB for industrial communication were used. The change in pressure was confirmed through the change in water level, the change in pressure was minimized, and a system for discharging liquid droplets was implemented.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.471-474
• /
• 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
• /
• 2002.10a
• /
• pp.95.1-95
• /
• 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...

• Journal of Sensor Science and Technology
• /
• v.33 no.5
• /
• pp.378-383
• /
• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.4
• /
• pp.143-147
• /
• 2018

Water levels are measured in various fields such as sewage treatment plants, water treatment plants, rivers, dams, factory storages' tanks. Ultrasonic instruments for water level measurement are expensive and are used for industrial field. Rapid advances in electronics have made it possible to build a wide variety of measurement, monitoring and control functions at low cost. This study was started to make ultrasonic level measurement system at low price. The system was constructed with an Arduino, an ultrasonic sensor and a temperature sensor for use in the experiment. The ultrasonic sensor measures the time from the sensor to the liquid surface. The temperature sensor measures the atmospheric temperature and improves the accuracy of the ultrasonic distance measurement by correcting the sound speed. Arduino controls measurements and calculates the water level. All components of the system are assembled into a device holder. Experiments with this system show that the water level measured by the system is very close to the actual value. This system is also inexpensive and easy to install and maintain, making it suitable for laboratory use.

• Journal of the Korean Magnetics Society
• /
• v.21 no.1
• /
• pp.32-36
• /
• 2011

We fabricated a sensor for measuring the water level and water temperature using GMR-SV (giant magnetoresistance-spin valve) device, simultaneously. It could be applied to the medical cooling system of the potassium titanylphosphate KTP) laser system for the therapy of a benign prostatic hyperplasia. The middle point of GMR-SV device was set to the near position of a high magnetic sensitivity with 2.8%/Oe. The sensitivity for the water level and water temperature of the fabricated sensor were $400\;m{\Omega}/mm$ and $100\;m{\Omega}/^{\circ}C$, respectively.

• Journal of Korean Society of Rural Planning
• /
• v.21 no.4
• /
• pp.177-186
• /
• 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.