- May 2022
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The PDMS ring and the free-standing membrane together formed an air gap structure that allowed the free-standing membrane to deform easily under an external force. The resulting devices are flexible and can have different sizes and geometries for different prosthetic applications
The authors determined the optimal PDMS thickness that would allow a sufficient air gap between the membrane and the sensor coil. In this case, the membrane could easily deform and its deflection was measured when an external force was applied.
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recorded from the sensor were converted into digital-frequency signals by using an LC oscillation circuit composed of a tactile sensor and a capacitor of 100 nF
In this experiment, the authors tested the ability to convert the analog signals from the sensor into digital-frequency signals. They loaded the sensor with 50, 113, and 1000 Pa shown in fig. 4B. These are applied pressures which are commonly experienced by humans throughout the day. The authors found that the number of pulse waveforms increased with increased loading, which is similar to human responses to force stimuli.
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not only perceived ultralow pressure but also had the ability to grasp heavy objects.
After the authors tested the ultralow pressure sensing ability of the sensor, they found that not only could the sensor detect ultralow pressures but that it could also detect pressures over 20 kPa. The means that sensor could also detect heavy objects as well as subtle sensations like wind blowing.
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Therefore, a subtle force can be detected by the tactile sensor with high magnetic field sensitivity and a near-linear response to magnetic field.
The authors determined that a frequency of 250 kHz produced the largest percent change (500%) in magneto-impedance, thereby yielding the highest sensitivity. This meant that a small force could be detected by the sensor with a high magnetic field sensitivity.
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- Mar 2022
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The reported tactile sensor exhibited a very high sensitivity of 4.4 kPa−1 and an ultralow detection limit of 0.3 Pa
The authors' found this information after their impedance and applied pressure experiment and ant experiment respectively. This showed the very high sensitivity of the sensor at an ultralow pressure range.
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Saraf et al. (34) introduced a light-harvesting and self-powered monolith tactile sensor.
The notable advancement in the article referenced here is the application of perovskite material within a monolithic tactile sensor. This material has properties of being ferroelectric and semiconducting which allows it to be made into a light harvesting, self-powered tactile sensor.
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The tactile sensor could distinguish a weight of 10 μN. By taking the contact area as about equal to 4 × 10−5 m2, we calculated the corresponding pressure detection limit to be equal to 0.3 Pa.
After the authors' water drop experiment, they found that the impedance increased with increasing volumes of water. Therefore, the device was able to "sense" the weight of the different volumes of water. They found that the device's detection limit was 0.3 Pa.
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The actions of the ant could be sensed. Figure 3C shows the moving trail of the ant, and Fig. 3D demonstrates the change of impedance of the tactile sensor with the moving ant. The impedance of the tactile sensor is about 38.57 ohms.
After the authors' ant experiment, they found that the sensor was able to detect the ant's movements across the sensor. This confirms the device's ability to detect changing tactile information.
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e-skin tactile sensors can be prepared by using flexible
This article displays how a piezoelectric tactile sensor array can be used to help people who have lost their sense of touch gain it back.
To learn more about the use of a piezoelectric tactile sensor array: https://www.cityu.edu.hk/research/stories/2021/04/29/skin-inspired-tactile-sensors-distinguish-diverse-stimuli-and-offer-hope-limb-injuries
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- Feb 2022
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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The dynamic sensing was demonstrated by placing small live insects of 0.8-mg mass onto the tactile sensor.
In this experiment, the authors created a way to test the sensor's ability to detect changing tactile information. To do this, they placed an ant on the sensor and let it walk around. The authors show the path of the ant on the sensor in fig. 3C. They found that the sensor was able to detect the ant's movements across the sensor. They were also able to detect the movement of the ant's antenna when it was still. The authors show the data from this experiment in fig. 3D.
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11. J. Kim, et. al, Stretchable silicon nanoribbon electronics for skin prosthesis. Nat. Commun. 5, 5747 (2014).
The artificial skin developed in this article had the ability to sense stimuli in highly variable external environments. It also had the ability to sense skin moisture and temperature.
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development of next-generation prosthetic limbs that replace or even surpass the sensing ability of humans is very important
Next-generation prosthetics is a growing field of research. Current prosthetics are unable to fully restore functionality to an amputated limb. The goal of prosthetics is to help patients recover mobility due to loss of a limb.
To learn more about next-generation prosthetics: https://www.jerseysbest.com/health/smart-prosthetics-state-of-the-art-technology-gives-amputees-more-control-over-their-limbs/
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The detection limit of the tactile sensor was further investigated by dropping water of different volumes (1 μl, equal to 10 μN) onto the tactile sensor
In this experiment, the authors created a different way to test the sensor's detection limits. They dropped different volumes of water on the sensor. The authors found that the impedance increased with increasing volumes of water. This means that the device was able to "sense" the weight of the different volumes of water. They found that the device's detection limit was 0.3 Pa. The authors show the data from this experiment in fig. 3B.
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stimuli
signal or input that evokes a specific functional reaction in an organ or tissue.
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The quality of life for persons with limb loss is greatly affected because of lack of tactile sensing capability
Amputation is a life altering event for an individual. It can affect a person's ability to move and interact with their environment. One of the senses lost with the loss of a limb is the sense of touch.
To learn more about amputation: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/amputation#:~:text=Amputation%20is%20the%20loss%20or,emotional%20trauma%20can%20complicate%20recovery
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There has been notable advancement in the field of designing prosthetic limbs integrated with rigid and/or flexible tactile sensors that are responsive to variable environments
The notable advancement in the article referenced here is a stretchable prosthetic skin. The artificial skin made in this reference article had enhanced ability to sense stimuli in highly variable external environments. It also had the ability to sense skin moisture and temperature.
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pascals
the standard unit of pressure or stress in the International System of Units (SI), equal to one newton per square meter.
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tactile
connected with the sense of touch
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bionic
having artificial body parts, especially electromechanical ones.
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prosthetic
an artificial body part
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