12 Matching Annotations
  1. May 2022
    1. The fabrication process for the tactile sensor based on Co AW and the air gap structure is shown in fig. S3.

      The authors chose to use a co-based amorphous wire (Co AW) for its strong magnetic properties. The researchers were able to use a B-H Loop Tracer machine to test the permeability of the wire. This test showed that as increasing frequency was applied, the wire was able to maintain a high permeability and impedance.

      Additionally, the authors determined the correct thickness of the PDMS ring and free standing membrane that would allow a sufficient air gap to be present between the magnetic particles and inductor. The air gap allows for pressure-induced deformations in the membrane which is detected by the changes in the magnetic flux through the inductor.

    2. Therefore, a minimum loading of 1.25 Pa (the contact area is about 4 × 10−5 m2 or 50 μN), beyond the sensing threshold value of humans (1 mN) (1), can be encoded as digital-frequency signals.

      This result is valuable, because it proves the author's tactile sensor can detect pressure load smaller than the sensing threshold of a human. The tactile sensor is able to encode a digital-frequency signal of 0.7-Hz pulse waveform when a loading of 1.25 Pa (approximately 50 μN) was placed on the tactile sensor. This loading is much smaller than the sensing threshold value of humans, which is approximately 1 mN.

    3. Besides, we expect that the sensitivity and detection limit of the sensor can be further improved by choosing GMI materials with a higher GMI ratio and by varying the thickness of the PDMS membrane through optimization of the polymer magnet and the fabrication method.

      This idea ties well to the Next Generation Science Standards Disciplinary Core Idea ETS1.B: Developing Possible Solutions.

      The authors here describe a way to test various physical models to improve the sensing capability of their tactile sensor. It is important to understand the creative process of developing a new design to solve an engineering problem, whether it is using physical models and/or computers. In this specific case, the researchers propose that testing a variety of different physical factors, such as various magnetic materials, PDMS thicknesses, and fabrication processes, can help optimize the tactile sensor's efficiency.

    4. Tee et al. (40) reported that the action potential of neurons was closely followed by the frequency of pulses.

      This group of researchers developed a skin-inspired mechanoreceptor, with output frequencies ranging between 0 and 200 hertz, which are pulses that mimic slow-adapting skin mechanoreceptors.

    5. impedance

      an electrical component's effective resistance to alternating current

  2. Mar 2022
    1. The LC oscillation circuit was composed of a circuit in which an inductor (L) and a capacitor (C) were applied in parallel.

      LC circuits is an important topic on the AP Physics C guidelines that falls under the Electricity and Magnetism section. The LC oscillation circuit in this tactile sensor plays a huge role in converting pressure loads into digital signals.

    2. Human skin perceives pressure stimuli on touch, which are subsequently transformed into physiological responses; these responses are transferred to the brain via the nervous system (1–4).

      This topics directly aligns with the AP Biology Essential knowledge 3.E.2. This standard focused on the detection, transmission, and integration of external and internal stimuli throughout the nervous system and how responses are produced based on them.

    3. 33. A. Miyamoto, et. al, Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes. Nat. Nanotechnol. 12, 907–913 (2017).

      This research group focused on using nanomeshes to design a long-lasting skin patch that reduced inflammation and irritation for the user without compromising data collection and accuracy. The fabricated patch is lightweight, ultrathin, stretchable, and has high-air permeability - all factors that promote user comfort. Overall, their device was able to detect temperature, touch, and pressure as well as acquire electromyogram recordings with minimal user discomfort.

    4. Miyamoto et al.

      This group fabricated inflammation-free, highly gas-permeable, ultrathin, lightweight and stretchable sensors that can be directly laminated onto human skin for long periods of time. Their unique device implemented nanomeshes, which aided in suppressing skin irritation and inflammation.

    5. B. C.-K. Tee, et. al, A skin-inspired organic digital mechanoreceptor. Science 350, 313–316 (2015).

      This paper talks about a power-efficient skin-inspired mechanoreceptor with a flexible organic transistor circuit that transduces pressure into digital frequency signals directly. Their DiTact system was able to mimic human tactile perception with slow/no frequency oscillation in the absence of pressure stimulation and increasing frequency with increased with pressures applied to the device. Overall, the device was capable of evoking action potentials at frequencies up to 200 Hz for prolonged intervals.

    6. Oddo et al. (38) reported an approach of intraneural stimulation that elicited discrimination of textural features by an artificial fingertip in intact and amputee humans.

      This publication describes a device that allows amputees to distinguish different textures using a sensorized artificial finger tip. This finger tip is unique because it includes a neuromorphic real-time mechano-neuro-transduction (MNT), a device that converts touch into nerve firing dynamics. These microsimulations are sent to an electrode, which is then directly attached to a nerve in a human subject. Both subjects with intact limbs and amputee subjects were able to distinguish differences in surface coarseness.

  3. Feb 2022