Rerkratn, Apinai
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Rerkratn, Apinai
Alternative Name
Rerkratn, A.
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apinai.re@kmitl.ac.th
24 results
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Item type:Publication, A simple amplitude detector-based demodulator for resolver converters(2010-12-01); This paper presents a simple method based on sinusoidal-amplitude detector for realizing the resolver-signal demodulator. The proposed demodulator consists of two full-wave rectifiers, two ±unity-gain amplifiers, and two sinusoidal-amplitude detectors with control switches. Two output voltages are proportional to sine and cosine envelopes of resolver-shaft angle without low-pass filter. Experimental results demonstrating characteristic of the proposed circuit are included. ©ICROS. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Internet-based conductivity measurement system with self-temperature compensation(2019-07-01); Kaewpoonsuk, AnuchaAn Internet-based conductivity measurement system with self-temperature compensation is presented in the paper. In order to get a simple and portable measurement system, a readout circuit in analog part is designed using only two operational amplifiers (opamps) connected with basic electronic components and energized using single supply voltage. An excitation voltage generated by the AD9833 module is applied to a conductivity sensor. The measured output DC voltages are found to be directly proportional to the conductivity of the solution. The NodeMCU ESP8266 WiFi dev board is used to determine the conductivity and measure the temperature whose effect on the conductivity is compensated. The measured results are sent to display on a smartphone by Blynk app. The conductivity measured by the proposed system is in good agreement with that due to the standard EC meter. A maximum error of measuring the conductivity at different temperatures of solution is 4.79% of full scale. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Simple and low-cost readout circuit for differential resistive sensors(2018-09-01); Kaewpoonsuk, AnuchaIn this paper, a simple and low-cost readout circuit for differential resistive sensors is presented. The realization method is based on the relaxation oscillation technique, which utilizes the operational amplifiers (op-amps) with a single supply voltage. The oscillating output Duty-Cycle is proportional to the difference of two sensing resistances. In comparison with the traditional voltage divider circuit or the Wheatstone bridge circuit or the previously reported readout circuit based on CCIIs, the proposed circuit can be interfaced with microcontroller without using an analog-to-digital converter. Theoretical predictions are supported by the PSPICE simulation results and the experimental data. In applying a slide potentiometer with changes of slider positions of ±15 mm, it is found that the maximum error of the proposed circuit is approximately-2.90% of full-scale. Copyright © 2018 Praise Worthy Prize S.r.l.-All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Real-time seafood quality monitoring system using interdigital sensor(2020-01-01); Many studies showed that seafood consumption contains many health benefits. However, the spoilage of such products causes the vast economic loss each year. An effective monitoring and inspection system for quality is required during the storage of these products. Most existing methods for such inspection require laboratory tests. In this study, the interdigital sensor was developed and applied to inspect the spoilage of seafood. The sensor was designed to monitor the change of impedance during spoilage progression of seafood. The result revealed that impedance of liquid decreased overtime. This coincides with the fact that spoilage of seafood generates ammonium ion which causes decrease in the impedance of the liquid. The designed sensor was then merged with the proposed system which consists of a sine wave circuit, a voltage control current source circuit, an interdigital sensor, an amplifier circuit, a rectifier circuit, a low-pass filter circuit, a comparator circuit and a display circuit. These circuits adjusted the signals received from the sensor to be proper to the application. The experiment was designed to have conditions similar to the real-world situation of how seafood is stored. The experimental results showed that the proposed system effectively indicated the change of seafood quality. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Real-time fault notification for billboard lighting system(2017-11-24); Kaewpoonsuk, AnuchaThis paper presents a technique to implement the alert system for the faults of billboard lighting system. The proposed system consists of the current sensor module SCT-013-005 used to measure the overall current consumption of the billboard lighting system, ARDUINO UNO R3 used as the controller to determine the faults, and GSM module used to remotely transmit faulty data to the data server as well as to the user mobile via short message service. The alert data composes the current consumption of lighting system, number of the bulbs with abnormal condition, and identification number of base station. In addition, the conditions for sending notifications can be set. The billboard lighting system using seven bulbs connected in parallel is employed to test the performance of the proposed notification system. Test results verify that the proposed system can function correctly. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Resistive-Sensor Interfacing Circuit for Remote Measurement Using CFOA(2024-01-01); ; ; Kaewpoonsuk, AnuchaAn alternative approach to implementing an interfacing circuit for resistive sensor-based remote measurement is presented. The proposed technique uses a Current Feedback Operational Amplifier (CFOA) as an active building block to produce an output voltage linearly related to the resistance of the sensor. Moreover, the accuracy of the output voltage is improved by the enhancement of CFOA. In addition, the proposed circuit provides compensation for the effects of lead-wire resistance. The performance of the proposed technique is discussed in detail and confirmed by PSPICE program simulation and experimental implementation. The resistance decade box is used in the experiment. The maximum error on the output voltage of the experimental results is about 0.4234 %. The experimental results show that the proposed technique provides good performance. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, ZigBee based wireless temperature monitoring system for shrimp farm(2015-12-23); Kaewpoonsuk, AnuchaThis paper proposes a design and implementation of wireless temperature monitoring system for shrimp farm based on ZigBee technology. The proposed system consists of three wire resistance temperature device (RTD) type PT-100, Current source circuit, XBee Pro module, 2.4 GHz antenna with gain 5dBi, Arduino Uno R3 microcontroller board and LabVIEW program for monitoring and control system. Experimental results with standard temperature bath show that the proposed system can monitor temperature with satisfied data. The maximum error of temperature is about 0.25 percents. The maximum range of system is about 500 meters. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Timer-Based Capacitance-to-Voltage Converter(2026-03-01); This article presents the design and analysis of a capacitance-to-voltage converter based on 555-timer Integrated Circuits (ICs) as the core design element. The circuit structure consists of two primary active components: two 555-timer ICs connected in conjunction with a low-pass filter circuit. The first 555-timer IC operates in astable mode to generate a signal that controls the timing of the second IC. The target capacitor or capacitive sensor to be measured is connected to the second 555-timer IC, which operates in monostable mode. The output signal from the second 555-timer IC is then converted into a DC voltage output using a low-pass filter circuit. The circuit was tested using laboratory capacitors in the range of 52.72 pF to 807.61 pF, and the data were analyzed using Microsoft Excel. The results showed excellent agreement with the measurements obtained from the GW INSTEK LCR-819. The maximum uncalibrated error was found to be −3.32% of full scale. After applying linear curve fitting in Excel, the maximum error was reduced to 0.92% of full scale, confirming the effectiveness of the calibration approach. Furthermore, the circuit was applied to measure the moisture content of paddy rice using a cylindrical capacitive sensor within the moisture range of 12.1% to 23.2%. The experimental data were fitted to a derived equation, which was then used to predict rice moisture content, producing results that corresponded closely with those obtained from the KETT PM-450 grain moisture meter. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Synthesis of simple interface circuit based on time-period detection technique for capacitance measurement(2011-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Ultrasonic measuring circuit using sample and hold method(2008-12-01);