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Triboelectric Energy-Harvesting Floor Tile
(2022-12-01)
Thainiramit, Panu
;
Jayasvasti, Subhawat
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Yingyong, Phonexai
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Nandrakwang, Songmoung
;
Isarakorn, Don
The aim of this study was to investigate the real-world electrical parameters that strongly affected the performance of a triboelectric energy-harvesting floor tile design: triboelectric material thickness, cover plate displacement distance or gap width, and cover plate pressing frequency, so that real-world specifications of the harvesting floor tile can be accurately specified. The structure of the designed triboelectric energy harvester, with readily available polytetrafluoroethylene (PTFE) film and aluminum foil, was simple and hence easy to fabricate, and the material cost was low. A square wave was used to simulate the pressing frequency on the test bench’s cover plate. The results showed that the voltage and current were proportional to the gap width, and the thinner the triboelectric layer thickness, the higher the output voltage and current. A test bench with a 0.2 mm thick PTFE triboelectric layer generated the highest energy output. In a later experiment, a triboelectric energy-harvesting floor tile (TEHFT) prototype was constructed with 0.1 and 0.2 mm thick PTFE layers. We found that at 2 Hz stepping frequency and 0.1 mm PTFE thickness, the optimal load and cumulative energy of the TEHFT were 0.8 MΩ and 3.81 mJ, respectively, while with 0.2 mm PTFE thickness, these two parameters were 1.1 MΩ and 7.69 mJ, respectively. The TEHFT with 0.2 mm thick PTFE layer was able to illuminate a series of 100 to 150 LEDs, sufficient power to drive small electronics and sensor nodes. This discovery provides important data on the structure, material, and contact surface area of a TEHFT that can be adjusted to suit specific requirements of a special function triboelectric energy harvester.
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Evaluation of harvesting energy from pedestrians using piezoelectric floor tile energy harvester
(2021-11-01)
Yingyong, Phonexai
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Thainiramit, Panu
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Jayasvasti, Subhawat
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Thanach-Issarasak, Nicharas
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Isarakorn, Don
This study determined the influences of several pedestrian parameters on the amount of energy harvested by a piezoelectric energy harvesting floor tile (EHFT), for the goal of providing a realistic harvested energy specification for an application in a certain pedestrian environment. Experiments were conducts to measure the original harvested energy in a laboratory and the harvested energy under a variety of pedestrian parameter values. The main outcomes were the following: the original, unadjusted harvested energy provided by one pedestrian step obtained in the laboratory was 35 mW<inf>rms</inf>; when ten people, weighing less than 50 kg or over 70 kg, stepped on the floor tile, the harvested energy was about 11.0 mJ and 32.0 mJ, respectively; When 30 people walked or ran over it without any fixed pattern, the harvested energy was about 289.0 mJ and 736.9 mJ, respectively; when 30 people walking in a row, separated by a gap of 0.5, 1, and 1.5 m, walking over the tile one by one, the stored energy was 401.0 mJ, 406.0 mJ, and 452.0 mJ, respectively. To conclude, two pedestrian parameters affected the harvested energy strongly pedestrian body weight and pace (walking or running), but pedestrian density did not affect the harvested energy of our developed EHFT strongly. Therefore, in an adjustment of a laboratory-obtained harvested energy into a realistic specification, the influences of those two pedestrian parameters had to be included, while pedestrian density could be ignored. These findings should be directly useful to new researchers and developers in their effort to formulate a realistic harvested energy specification for their developed EHFT.
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Technique for measuring power across high resistive load of triboelectric energy harvester
(2021-07-01)
Jayasvasti, Subhawat
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Thainiramit, Panu
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Yingyong, Phonexai
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Isarakorn, Don
This paper proposed a more-accurate-than-conventional measurement technique for determining electrical power across exceptionally high-impedance of triboelectric energy harvester (TEH). The key idea of this proposed technique was to measure the voltage across an introduced, parallelly-connected resistor divider to the oscilloscope instead of the voltage across the harvester. An experiment was set up to verify the measurement accuracy performance of this technique against the ideal theoretical values. The maximum percentage error found was only 2.30%, while the conventional measurement technique could not be used to measure voltage across high impedance TEH at all because the readings were not accurate, i.e., the measurement error would be at least over 10%. Therefore, we concluded that this proposed technique should always be used instead of the conventional measurement technique for power measurement of any TEH. A suggestion that we would like to offer to researchers investigating or developing a TEH is that, in using our measurement technique, a good starting point for a load to probe resistance ratio is 1:10, a ratio that worked well for our TEH test bench that we developed.
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Potential of Piezoelectric Floor Tile for Harvesting Energy from Human Footsteps
(2021-01-01)
Thanach-Issarasak, Nicharas
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Jayasvasti, Subhawat
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Yingyong, Phonexai
;
Isarakorn, Don
Since the last decade, piezoelectric floor tile energy harvesters have been developed to convert wasted mechanical energy into usable electrical energy. Our team has also been developing and improving this kind of harvester, abbreviated as EHFT, for several years. One of the developmental problems was in reporting a realistic value of energy generated by EHFT because it depended heavily on many real-world factors. The objective of this study was to determine such realistic value by simulating those factors with a real-world traffic of 30 people entering a building. An EHFT together with proper electrical measurement devices were installed at the entrance of a building in King Mongkut's Institute of Technology, Thailand, and a group of 30 people were asked to step on it while entering the building. The value of the cumulative generated energy from the EHFT with those participants for a time duration of 600 s was found to be 450.26 mJ. This value was sufficiently high to constantly power a temperature sensor during a whole workday. Therefore, we are in the process of developing an automated Covid-19 detection station in which the temperature sensor will be powered by this EHFT.
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Design and evaluation of double-stage energy harvesting floor tile
(2019-10-01)
Isarakorn, Don
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Jayasvasti, Subhawat
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Panthongsy, Phosy
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Janphuang, Pattanaphong
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Hamamoto, Kazuhiko
This paper introduces the design and characterization of a double-stage energy harvesting floor tile that uses a piezoelectric cantilever to generate electricity from human footsteps. A frequency up-conversion principle, in the form of an overshooting piezoelectric cantilever, plucked with a proof mass is utilized to increase energy conversion efficiency. The overshoot of the proof mass is implemented by a mechanical impact between a moving cover plate and a stopper to prevent damage to the plucked piezoelectric element. In an experiment, the piezoelectric cantilever of a floor tile prototype was excited by a pneumatic actuator that simulated human footsteps. The key parameters affecting the electrical power and energy outputs were investigated by actuating the prototype with a few kinds of excitation input. It was found that, when actuated by a single simulated footstep, the prototype was able to produce electrical power and energy in two stages. The cantilever resonated at a frequency of 14.08 Hz. The output electricity was directly proportional to the acceleration of the moving cover plate and the gap between the cover plate and the stopper. An average power of 0.82 mW and a total energy of 2.40 mJ were obtained at an acceleration of 0.93 g and a gap of 4 mm. The prototype had a simple structure and was able to operate over a wide range of frequencies.
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Indoor positioning system on identification of neurodegenerative disease: A comparative study of BLE versus RFID
(2019-07-01)
Jayasvasti, Subhawat
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Isarakorn, Don
This paper introduces the feasibility examination of indoor positioning system using the Bluetooth low energy (BLE) and the radio-frequency identification (RFID) devices to further apply in the diagnosis of neurodegenerative disease leading an unusual human body motion. Experimentally, a BLE module and a RFID tag are simulated to be the wearable devices mounted to human body, moving with common body motions. Their movements affecting on position tracking efficiency are investigated through smartphone and ultra-high frequency RFID reader, respectively. The results show that a BLE device presents the best position sensing ability.
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Study of Interaction between Operational Clock-Frequency and Energy Consumption of Microcontrollers for Wireless Sensor Applications
(2018-08-14)
Jayasvasti, Subhawat
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Isarakorn, Don
This work focuses on the diagnosis of energy consumption of commonly used microcontrollers with various driving clock-frequency. The interaction among the driving clock-frequency, processing time and current consumption are determined to be a guidance for the design of low-power wireless sensor applications. In implementation, the microcontrollers are supposed to process the data following the operational procedures of wireless sensor application, which is programmed to solve mathematical equation with various driving clock-frequencies, and then sleep to reduce the power consumption. With a single circle procession, the current consumption at each driving clock-frequency are captured and analyzed. As the results, the current consumption is proportional to the driving clock-frequency, however energy consumption is minimized at highest clock-frequency.
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Comparative study of QCM analyzers based on pierce oscillator and electromechanical impedance techniques
(2017-02-21)
Jayasvasti, Subhawat
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Isarakorn, Don
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Nundrakwang, Songmoung
This paper presents a comparison between pierce oscillator and impedance analysis techniques for measuring the frequency of the quartz crystal. The QCM analyzer based on pierce oscillator is designed, realized, and then compared to the impedance analyzer (Type bode 100). The comparison is focused on accuracy and precision of measurement. The pierce oscillator in a completed-chip is employed in the QCM analyzing device in order to simplify the circuit of system. The frequency drift and standard deviation (SD) values which are obtained from resonant frequency measurement are studied in order to investigate the accurate and precise measurement of devices. In the experiment, an AT-cut quartz disc of crystal oscillator package HC49U is unloaded and loaded while it is being measured the frequency. From the experimental results, the QCM analyzer based on pierce oscillator and impedance analyzer have the approximate accuracy and precision of measurement. The QCM analyzer based on pierce oscillator has lower sensitivity due to the frequency drift.

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