Etichetă: piele artificiala

Pielea electronică inspirată de meduze se aprinde atunci când este rănită(Jellyfish-inspired electronic skin glows when it gets hurt)

Tehnologiile electronice pentru piele pentru proteze și roboți pot detecta cea mai mică atingere sau briză. Dar ciudat, senzorii care fac acest lucru posibil nu răspund efectiv la o lovitură dăunătoare.
Acum cercetatorii raporteaza in materialele si interfetele aplicate ACS ( „piele electronica duala cu senzatie integrata tactila si avertizare vizuala a prejudiciului” ), dezvoltarea unei piele electronica inspirata de meduze care straluceste cand presiunea impotriva ei este suficient de mare pentru a provoca un prejudiciu .

Posted: Nov 01, 2017

Jellyfish-inspired electronic skin glows when it gets hurt

(Nanowerk News) Electronic-skin technologies for prosthetics and robots can detect the slightest touch or breeze. But oddly, the sensors that make this possible do not respond effectively to a harmful blow.
Now researchers report in ACS Applied Materials & Interfaces („Dual-Mode Electronic Skin with Integrated Tactile Sensing and Visualized Injury Warning”) the development of a jellyfish-inspired electronic skin that glows when the pressure against it is high enough to potentially cause an injury.
An electronic skin glows when a transparent 'W' is pressed onto it, and a voltage is applied
An electronic skin glows when a transparent ‘W’ is pressed onto it, and a voltage is applied (bottom). (© American Chemical Society)
An electronic skin that can mimic the full range of biological skin’s sensitivity has great potential to transform prosthetics and robotics. Current technologies are very sensitive, but only within a narrow range of weak pressures. Under high pressures that could cause damage, the electronic skins’ sensitivity fades.
To address this shortcoming, Bin Hu and colleagues at the Huazhong University of Science and Technology turned to the Atolla jellyfish for inspiration. This bioluminescent, deep-sea creature can feel changes in environmental pressure and flashes dramatically when it senses danger.
Building on the idea of a visual warning in response to a physical threat, the researchers combined electric and optical systems in a novel electronic skin to detect both slight and high-force pressures. They embedded two layers of stretchy, poly-dimethysiloxane, or PDMS, film with silver nanowires. These layers produce an electrical signal in response to slight pressures, such as those created by a breeze or contact with a leaf. Sandwiched in between the silver nanowire electrodes is a PDMS layer embedded with phosphors. This layer kicks in and glows with growing intensity as the physical force increases.
The researchers say this approach more closely copies the wide range of pressures the human skin can feel.
Source: American Chemical Society

Un senzor tactil microfluidic bazat pe un design senzor de presiune al diafragmei (A microfluidic tactile sensor based on a diaphragm pressure sensor design )

cercetatorii raporteaza un senzor tactil microfluidic bazat pe un design al senzorului de presiune al diafragmei.
Dezvoltarea senzorilor de presiune flexibili are diverse aplicații potențiale în robotica moale, electronice portabile și piele artificială artificială.
Ca o dovadă a conceptului, cercetătorii au proiectat și fabricat o brățară PDMS cu un senzor de presiune cu membrană microfluidică încorporată pentru măsurarea măsurătorilor dinamice ale impulsurilor.

Posted: Aug 28, 2017

A microfluidic tactile sensor based on a diaphragm pressure sensor design

(Nanowerk News) In a new paper in Advanced Materials („Wearable Microfluidic Diaphragm Pressure Sensor for Health and Tactile Touch Monitoring”), researchers report a microfluidic tactile sensor based on a diaphragm pressure sensor design.
The development of flexible pressure sensors has various potential applications in soft robotics, wearable electronics, and artificial electronic skins.
Microfluidic tactile diaphragm pressure sensor
Microfluidic tactile diaphragm pressure sensor. a) Optical image of a finished microfluidic diaphragm sensor. b) Schematic layout of the diaphragm sensor and c) the equivalent circuit schematic forming an equivalent Wheatstone bridge circuit. d) Simulation of the normal stress for the radial sensing grids (?r) (along X-axis) and the normal stress for the tangential sensing grids (σt) (along Y-axis) of the sensor under 1 kPa pressure applied over a 9 mm diameter and e) a schematic diagram indicating testing conditions. (© Wiley-VCH Verlag) (click on image to enlarge)
This novel diaphragm pressure sensor design utilizing an embedded equivalent Wheatstone bridge circuit makes the most of tangential and radial strain fields, allowing the researchers to achieve a combination of high sensitivity, linearity, low limit of detection, high resolution, and temperature self-compensation.
The usage of the Wheatstone bridge design also provides built-in temperature compensation allowing for operation between 20 and 50°C without external offsets.
Due to its performance, the diaphragm pressure sensor meets the requirement of a variety of potential applications. Among many, one feasible and effective health monitoring application is heart-rate monitoring.
As a proof of concept, the researchers designed and fabricated a PDMS wristband with an embedded microfluidic diaphragm pressure sensor to measure dynamic pulse measurements.
Tactile sensing glove
Tactile sensing glove. a) Photograph of hand-shaking wearing the PDMS tactile sensing glove. b) Schematic of the PDMS tactile sensing glove. c) Photograph of the tactile sensing glove worn while grasping a grape. d) Real-time response recorded from the corresponding thumb and index finger sensors for gently grasping and releasing the grape. e) Photograph of the tactile sensing glove worn while gripping a bat and the corresponding output voltage map across the sensors within the glove. (© Wiley-VCH Verlag) (click on image to enlarge)
„The detection limit of our sensor has been shown to be below 100 Pa with sub-50 Pa resolution,” the authors note. „The extremely low detection limit and resolution combined with an ultrafast response time of 90 ms allows for the sensor to be used in a wide range of applications.”
As the team demonstrates, the liquid-state diaphragm pressure sensors may be utilized as either standalone devices for monitoring pressure at a specific point or into large arrays for tactile mapping in a variety of electronic skin and smart textile applications for wearables, robotics, and beyond.
By Michael is author of two books by the Royal Society of Chemistry: Nano-Society: Pushing the Boundaries of Technology and Nanotechnology: The Future is Tiny.

Read more: A microfluidic tactile sensor based on a diaphragm pressure sensor design

Culoarea piele electronică schimbătoare de culori ar putea avea utilizări tehnologice și protetice uzate(Color-shifting electronic skin could have wearable tech and prosthetic uses)

am explorat efectul substratului (subiacent) asupra comportamentului electromecanic al grafenului;în timp ce știința a reușit să replice aceste abilități cu pielea artificială, schimbările de culoare sunt adesea vizibile doar cu ochiul liber când materialul este pus sub o întindere mecanică imensă

Stimp11

O piele inteligentă analogică care este auto-alimentată(An analogue smart skin that is self-powered )

„Pielea inteligentă analogică are în mod evident avantaje în ceea ce privește rezoluția și consumul de energie”, spune ea. „Sper ca munca noastră să atragă mai multă atenție pe domeniul pielii inteligente analogice. În plus, va contribui la zonele de inteligență artificială și electronică portabilă, deoarece senzorul de înaltă rezoluție auto-alimentat oferă o soluție pentru aplicații inteligente pentru piele

Posted: Apr 08, 2016

An analogue smart skin that is self-powered

(Nanowerk Spotlight) In order to make robots and robotic technology more human-like and more human-friendly, smart skin technology is a critical element that helps robots sense the world. These electronic or smart skins could help machines to accurately perceive the environment and better assist human owners.However, conventional smart skins – no matter if they are based on resistance, capacitance or transistors – all need a power supply. It’s kind of awkward for users to have a high-tech, state-of-the-art thin, flexible and light-weight smart skin and have to power it with a hard and heavy battery which can just work for hours.Furthermore, in conventional smart skins higher resolution always means higher energy consumption and complex circuits. These two aspects need to be carefully balanced to result in a practical device. So the obvious question is: Is it possible to achieve higher resolution and at the same time reduce energy consumption?A self-powered smart skin as the one just recently developed by a team of Chinese researchers fundamentally solves this problem. In this work, the scientists combine the triboelectric effect and planar electrostatic induction and apply it in a subtle device structure for the first time to create a self-powered analogue smart skin.Structure of analogue smart skinsStructure of analogue smart skins. (a) Schematic diagram of an analogue smart skin. (b) Optical image of the transparent, flexible, and lightweight smart skin. The smart skin with a honey bee landing on it will not deform the peony. (c) SEM image of microstructures on the PDMS film. (d) SEM image of the silver nanowire electrodes. (Reprinted with permission by American Chemical Society)Reporting their findings in ACS Nano („Self-Powered Analogue Smart Skin”), a team led by Prof. Haixia Zhang at the National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Peking University, presents a self-powered analogue smart skin to detect location as well as contact velocity, based on a single-electrode contact electrification effect and planar electrostatic induction.In this paper, the team presents two significant achievements. The first is that their smart skin is intrinsically self-powered.”We use spontaneous triboelectric charges, combined with planar electrostatic induction, to sense the touch applied on the smart skin,” Zhang explains to Nanowerk. „Triboelectric charges occur in our daily life everywhere when two surfaces touch each other. And when the charged surface approaches a metal block (or electrode) it will induce the opposite charge, which is the so-called ‘electrostatic induction’ effect.”The beauty of this approach is that it makes use of the charges from triboelectric effect – which exist everywhere. Imagine a scenario, when you want to drink some coffee: you walk towards a table, and by doing so the opposite charges will be generated on the surface of shoes and ground respectively; you pick up the cup to drink, and the opposite charges will be generated on the skin of your palm and the handle of the cup; furthermore, even swallowing the coffee will generate charges on the surface of your digestive tract and the coffee.The Chinese researchers utilize these spontaneous – but often be ignored – charges to make their smart skin completely self-powered.The intensity of the electrostatic induction effect depends on the distance between the charged surface and the metal electrode. The scientists use fixed electrodes to detect the intensity of the electrostatic induction effect, allowing them to confirm the location based on the relative intensity.That way, no extra power supply is required for operating the analogue smart skin.The second achievement is that only four electrodes are necessary to achieve millimeter bi-dimensional resolution (precision) because of the utilization of analogue localizing method to sense the touch stimulation.”Compared with the previous works (see references 1-3 below), this smart skin reduces the number of electrodes remarkably,” Zhang points out. „This helps a lot to reduce the complexity of the signal processing circuit. Although using less electrodes, our smart skins achieve 1.9 mm resolution, much better than previous results.”She notes that, compared with digital smart skins which have been studied extensively, analogue smart skins still need more in-depth study.”Analogue smart skins have obviously advantages at resolution and energy consumption,” she says. „I hope our work can draw more attention to the field of analogue smart skins. Furthermore, it will contribute to the areas of artificial intelligence and portable electronics as the self-powered high-resolution sensor offers a solution for smart skin applications.”Use of smart skin on an artificial handUse of smart skin on an artificial hand. (a) Photograph of an artificial hand covered by two-dimensional analogue smart skins on the curved back of the hand and one-dimensional analogue smart skins on the middle finger. (b) Voltage output when a honey bee approaches and leaves the two-dimensional smart skin swiftly. (c,d) Voltage ratios of electrodes a-d. (e) Voltage output when the two-dimensional smart skin on the artificial hand is touched. (f) Location result of analogue smart skins. The testing point is (2.50, 2.50), and the result is (2.53, 2.50), with a slight deviation of only 0.3 mm. (Reprinted with permission by American Chemical Society) (click on image to enlarge)Going forward, the team will work on the stretchability of their smart skin (the current version is not stretchable) and on improving the resolution. According to the team, due to the theoretically infinite resolution, there still is plenty of room to improve on the current performance. Furthermore, they will try to integrate more sensing parameters as well as signal transmission in the design.Last but not the least, they will explore approaches to shield the smart skin from environmental interference, which is critical for practical applications.Zhang notes that the current device design provides opportunities for including additional sensing capabilities such as temperature, contact velocity, or gas composition.References1) Takao Someya’s Group,36 electrodes for 64 square centimeter smart skins. Kaltenbrunner, M, et al. „An ultra-lightweight design for imperceptible plastic electronics.” Nature 499.499(2013):458-63.2) Zhenan Bao‘s Group, 16 electrodes for 4 square centimeter smart skins. Lipomi, Darren J., et al. „Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes.” Nature Nanotechnology 6.12(2011):788-792.3) Do Hwan Kim’s Group, 14 electrodes for 16 square centimeter smart skins. Kim, So Young, et al. „Highly Sensitive and Multimodal All-Carbon Skin Sensors Capable of Simultaneously Detecting Tactile and Biological Stimuli.” Advanced Materials 27.28(2015):4178-4185.By Michael is author of two books by the Royal Society of Chemistry: Nano-Society: Pushing the Boundaries of Technology and Nanotechnology: The Future is Tiny. Copyright © Nanowerk

Read more: An analogue smart skin that is self-powered

Dispozitive electronice extensibile, care au o lungime cvadruple

ar putea fi folosit pentru senzori concepuți pentru a monitoriza anumite funcții biologice.Ideale pentru pielea artificială pe proteze sau mașini robotizateÎnlătură termen: îmbrăcăminte conectată și senzori pe corp îmbrăcăminte conectată și senzori pe corp

Posted: Feb 29, 2016

Stretchable electronics that quadruple in length (w/video)

(Nanowerk News) EPFL researchers have developed conductive tracks that can be bent and stretched up to four times their original length. They could be used in artificial skin, connected clothing and on-body sensors.
stretchable electronics
Conductive tracks are usually hard printed on a board. But those recently developed at EPFL are altogether different: they are almost as flexible as rubber and can be stretched up to four times their original length and in all directions. And they can be stretched a million times without cracking or interrupting their conductivity. The invention is described in an article published today in the journal Advanced Materials („Intrinsically Stretchable Biphasic (Solid–Liquid) Thin Metal Films”).
Both solid and flexible, this new metallic and partially liquid film offers a wide range of possible applications. It could be used to make circuits that can be twisted and stretched – ideal for artificial skin on prosthetics or robotic machines. It could also be integrated into fabric and used in connected clothing. And because it follows the shape and movements of the human body, it could be used for sensors designed to monitor particular biological functions.
“We can come up with all sorts of uses, in forms that are complex, moving or that change over time,” said Hadrien Michaud, a PhD student at the Laboratory for Soft Bioelectronic Interfaces (LSBI) and one of the study authors.
Extensive research has gone into developing an elastic electronic circuit. It is a real challenge, as the components traditionally used to make circuits are rigid. Applying liquid metal to a thin film in polymer supports with elastic properties naturally seems like a promising approach.
Thin and reliable
Owing to the high surface tension of some of these liquid metals, experiments conducted so far have only produced relatively thick structures. “Using the deposition and structuring methods that we developed, it’s possible to make tracks that are very narrow – several hundredths of a nanometer thick – and very reliable,” said Stéphanie Lacour, holder of the Bertarelli Foundation Chair in Neuroprosthetic Technology and who runs the lab.
Apart from their unique fabrication technique, the researchers’ secret lies in the choice of ingredients, an alloy of gold and gallium.
“Not only does gallium possess good electrical properties, but it also has a low melting point, around 30o,” said Arthur Hirsch, a PhD student at LSBI and co-author of the study. “So it melts in your hand, and, thanks to the process known as supercooling, it remains liquid at room temperature, even lower.” The layer of gold ensures the gallium remains homogeneous, preventing it from separating into droplets when it comes into contact with the polymer, which would ruin its conductivity.
Source: By Sarah Perrin, École polytechnique fédérale de Lausanne (EPFL)

Read more: Stretchable electronics that quadruple in length (w/video)