The authors made a multilayered electric dermis to provide tactile information to an amputee. The prosthesis and amputee demonstrate the ability to differentiate non-painful or painful stimuli using sensory feedback and a pain reflex feedback control system.

This link is to an article on the "Brighter Side of News" posted on February 26, 2022. This article is about how scientists developed an artificial sensory receptor that can send signals to be analyzed in real time.

https://www.thebrighterside.news/post/electronic-skin-that-can-feel-in-real-time-just-like-humans-do

The authors conducted an experiment to optimize their tactile sensor. They found that a PDMS ring height of 1.3 mm allows the sensor to work in the most sensitive range.

It takes less force to activate stimuli for the sensor than it would for human skin. This means the tactile sensor is more sensitive than human skin, which makes it an efficient replacement for those who suffer from limb loss.

The polymer magnet with a magnetization of 0.3 emu and PDMS ring height of 1.3 mm yields a sensor that works at the most sensitive range. This means that this device has been optimized for further testing and application.

The authors added vertical forces to the sensor and measured the impedance. This was done to show that the sensor is able to distinguish between noise and subtle pressure.

This paper is a review article focusing on the strategies, technology, and desired performance of electronic skin devices. The paper introduces transduction mechanisms that are commonly used in e-skins. They also write about technical improvements for stretchability, sensitivity, and resolution properties for tactile sensing. They also highlight recent breakthroughs and development trends for e-skin in 2015.

This paper focuses on the integration of organic field-effect transistors and rubber pressure sensors fabricated using low cost processing technology. They took pressure images with flexible active matrix drivers with organic transistors. All materials in this device are soft except for the electrodes. The maximum effective device area is 8x8 cm squared, and contains a 32x32 array of pressure sensors. The device is electrically functional, even when wrapped around a cylindrical bar with a diameter of 4 millimeters.

This experiment shows the changes in frequency under different loads. The authors tested their tactile sensor under various pressure and frequency conditions that mimic the human response to force stimuli. Here, they can determine the tactile input (pressure) by the frequency (of frequency shift) measured by the sensor. The authors derived an equation relating the frequency to pressure.

This experiment was done in order to find the optimal height at which the inductive sensing element works within a magnetic field range of 0-6.2 Oe. They measured impedance for polymer magnets with different magnetizations approaching the sensing element. For each magnet, there is a height at which the sensor was most sensitive. For the maximum region of sensitivity, they chose the magnet with a magnetization of 0.3 electromagnetic units (emu) at a height of 1.3 mm.

Magneto-impedance is a function of frequency. In order to optimize the sensing component of the device, the authors wanted to determine which frequency yielded the highest percent change in magneto-impedance. They tested a range of frequencies from 0.5 kHz to 500 kHz. It was determined that the frequency of 250 kHz produced the largest percent change (500%) in magneto-impedance, and therefore the tactile sensor will be most sensitive when operated at this frequency.

Scientists, engineers, and clinicians need to work together to develop brain-computer interfaces (BCI) towards controlling artificial limbs with skill and speed approaching that of an able-bodied person.

In this experiment, they wanted to test the sensitivity at different frequencies. The sensitivity of the device increased as the frequency increased, but decreased after the frequency exceeded 250 kHz. That means the optimal frequency is 250 kHz, which is consistent with the optimal frequency of the inductive sensing element.

In this experiment, the authors wanted to determine the change of the magneto-impedance ratio that was caused from a force being applied to the polymer magnet. They tested four different frequencies by applying a downward force (displacement). As displacement increased, the magneto-impedance ratio decreased.

This paper draws inspiration from sensory (afferent) nerves to make flexible organic electronics. Afferent nerves carry sensations such as touch, pain, and temperature. The authors combined a pressure sensor, ring oscillator, and an ion gel-gated transistor to form an artificial mechanoreceptor. Their afferent nerve can detect movement, simultaneous pressure inputs, and distinguish braille characters.

A magnet obtained by embedding magnetic particles (made of NdFeB) into an elastomer (PDMS).

This paper draws inspiration from sensory (afferent) nerves to make flexible organic electronics. Afferent nerves carry sensations such as touch, pain, and temperature. The authors combined a pressure sensor, ring oscillator, and an ion gel-gated transistor to form an artificial mechanoreceptor. Their artificial nerve can collect pressure information from 1 to 80 kilopascals. It transforms the pressure information into action potentials ranging from 0 to 100 hertz. Their afferent nerve can detect movement, simultaneous pressure inputs, and distinguish braille characters.

This article provides a comprehensive summary of giant magneto-impedance. It covers the fundamental understanding of GMI phenomena, properties of GMI materials, and application of GMI based magnetic sensors. This is a helpful summary to further understand the effect of GMI and application in the current paper.

This report demonstrates the first energy-harvesting electronic-skin (EHES) device capable of differentiating and generating energy from stimuli such as normal pressure, lateral strain, bending, and vibration. The authors use the stretchability of their device to measure the change in capacitance and film resistance due to lateral strain. The EHES had a high pressure sensitivity compared to previous capacitive sensors, and was capable of harvesting different mechanical stimuli with voltage and current generation in the range of 10 volts.

This paper is interested in developing a brain-computer interface to provide control of a robotic upper limb as well as laying out a road map of resources and procedures for implanted neuroprosthetic devices. Motor BCI's have the potential to assist people with disabling injuries and lost limbs. This is complex and expensive research, and there have been very few clinical trials with implanted BCIs in people with motor impairments.

This paper reports on a stretchable electronic skin that is designed to be worn like a glove. The glove monitors live finger movement and registers distributed pressure along the entire length of the finger. The sensory skin is made of elastic materials and does not impede hand movement. Capacitive pressure sensors with stretchable gold thin-film electrodes and porous silicone foam display high sensitivity across the dynamic pressure range of human skin. Pressure sensors in the glove are distributed along the grasping region of the finger, with strain sensors along the back of the finger. The glove is successfully used in grasping and manipulation tasks.

Structures of an object, organism, or material with a typical feature length scale of 1-100 micrometers

This paper describes the first stretchable energy-harvesting electronic-skin device that is capable of differentiating and generating energy from pressure, bending, and vibration. The device had a maximum pressure sensitivity of 1.5 kPa-1, which is higher than the previously reported stretchable capacitive pressure sensors.

Inner layer of the skin tissue containing blood capillaries, nerve endings, sweat glands, and hair follicles.

Receptors typically located on cell membrane that relay external mechanical stimuli such as pressure, touch, or motion.

Synthetic materials/methods that mimic biological materials/mechanisms.

A therapy that uses low-voltage electrical current for pain relief, also known as TENS.

Nerve signals that occur when a neuron sends information away from the cell body. The action potential itself is a burst of electrical energy.

A circuit containing both an inductor (L) and capacitor (C) that oscillates by shifting the energy between the electric and magnetic fields.

An external magnetic field causing a large variation in the electrical impedance of the material.

They passed a sinusoidal driving current through the inductive sensing element and measured the impedance at different magnetic fields. The magnetic field sensitivity of the inductive sensing element was expressed as equation 3. This experiment concluded that a subtle force can be detected by the tactile sensor with high magnetic field sensitivity and a near linear response to magnetic field.

This paper describes a flexible and transparent e-skin device that was achieved by combining silk-molded micro-patterned PDMS with single walled carbon nanotube ultra-thin films. This device has great pressure sensing performance, but it is a challenge to form large-scale and uniform e-skin with cost effective fabrication methods.

Describes any large system of integrated circuits that mimic the nervous system.

A pain receptor that responds to damaging stimuli by sending the "threat" signals to the spinal cord and brain.

Inorganic nano-structured two-dimensional material.

A three-terminal active organic semiconductor device where the output current is controlled by an electric field generated by the input voltage. These are compact and have lower power consumption.

A device that exhibits a change in resistance when it is strained.