scholarly journals Integration of a Thin Film PDMS-Based Capacitive Sensor for Tactile Sensing in an Electronic Skin

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Sara El-Molla ◽  
Andreas Albrecht ◽  
Engin Cagatay ◽  
Philipp Mittendorfer ◽  
Gordon Cheng ◽  
...  

We present a capacitive force sensor based on a polydimethylsiloxane (PDMS) film integrated into a printed circuit board (PCB) on a flexible substrate whose layout is defined by inkjet printing. The influence of the dielectric thickness on the sensor behavior is presented. The thinner PDMS film of about 45 μm shows a sensitivity of up to 3 pF/N but poorer dynamic response. The dielectrics with thicknesses above 200 μm show a significantly reduced sensitivity. The best compromise between sensitivity and dynamic response is found for PDMS film of about 100 μm, showing about 1.1 pF/N and less than 15 s of recovery time. This film is integrated into a flexible PCBS including a microcontroller capable of evaluating the sensor. Interconnects of the circuit are defined by silver nanoparticles deposited by inkjet printing. The working principle of the circuit is demonstrated, proving that this simple approach can be used for artificial skin applications.

2014 ◽  
Vol 21 (4) ◽  
pp. 911-918 ◽  
Author(s):  
T. Vu Quoc ◽  
H. Nguyen Dac ◽  
T. Pham Quoc ◽  
D. Nguyen Dinh ◽  
T. Chu Duc

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Boyoung Kim ◽  
Minyong Choi ◽  
Seung-Woo Son ◽  
Deokwon Yun ◽  
Sukjune Yoon

Purpose Many manufacturing sites require precision assembly. Particularly, similar to cell phones, assembly at the sub-mm scale is not easy, even for humans. In addition, the system should assemble each part with adequate force and avoid breaking the circuits with excessive force. The purpose of this study is to assemble high precision components with relatively reasonable vision devices compared to previous studies. Design/methodology/approach This paper presents a vision-force guided precise assembly system using a force sensor and two charge coupled device (CCD) cameras without an expensive 3-dimensional (3D) sensor or computer-aided design model. The system accurately estimates 6 degrees-of-freedom (DOF) poses from a 2D image in real time and assembles parts with the proper force. Findings In this experiment, three connectors are assembled on a printed circuit board. This system obtains high accuracy under 1 mm and 1 degree error, which shows that this system is effective. Originality/value This is a new method for sub-mm assembly using only two CCD cameras and one force sensor.


2020 ◽  
Vol 12 (5) ◽  
pp. 356-366
Author(s):  
Salma El-Sawy ◽  
Wasim Nawaz ◽  
Mohamed Osama ◽  
Ahmet Tekin

AbstractThis paper discusses the design of chip-less RFID tags of a standard pocket size of 69 mm by 156 mm. These tags are based on lumped elements of copper metal traces constructed on a thin polyamide flexible substrate. Moreover, a low-cost single-chip Bluetooth detector circuit system is demonstrated. Two different detection methods: variable coil load coupling and optical light intensity detection were combined to yield 256 unique ID codes. In the first method, by utilizing simple 4 MHz digital drivers and an integrated analog to digital converter (ADC) in the reader controller; various inductively coupled resonant loads corresponding to multiple distinct tags could be differentiated, yielding eight different (3-bit) ID codes. The additional via-based hole pattern reflectometer method creates additional 32 distinct levels (5-bit) utilizing 650 nm visible light-emitting diode and a simple trans-impedance operational along with the same analog ADC pins of a Bluetooth controller. The printed circuit board trace coil on the two-layer low-cost FR-4 waterproof sealed detector unit is simultaneously used as a Qi wireless power receiver to charge the120 mAh 2450 Lithium Polymer (LiR) battery. The device could remain operational for more than a month with a single charge; remaining connected with a mobile device and enabling 10 readouts daily.


Author(s):  
Tran Thi Thuy Ha ◽  
Nguyen Dac Hai ◽  
Bui Thanh Tung

Abstract: This paper presents the design, fabrication and operation of a highly symmetrical two-axis capacitive sensor. The proposed sensor consists of five electrodes, including of an excitation electrode and two pairs of sensing electrodes with exactly the same dimensions, arranged at identified symmetrically locations on a 3D printed hollow sphere, which containing dielectric medium formed by the partly filled oil and the remaining air. The proposed sensor can measure the tilt angle about the x-axis and y-axis with symmetrical outputs. The proposed sensor is fabricated using a rapid prototyping technology and mounted on the surface of a printed circuit board (PCB) for mechanical packaging and signal processing. Experimental measurement results show that the sensor system can measure the tilt angle in both the x- and y-axis with sensitivity of 103 mV/degree and resolution of ±1 degree in the range of -30 degree to +30 degree. This sensor system can be used in many military and consumer applications. Keywords: Capacitive sensor, Fluidic sensor, Two-axis tilt angle sensor.


Sensor Review ◽  
2019 ◽  
Vol 39 (4) ◽  
pp. 525-541 ◽  
Author(s):  
Partha Pratim Ray ◽  
Dinesh Dash ◽  
Debashis De

Purpose Background: Every so often, one experiences different physically unstable situations which may lead to possibilities of suffering through vicious physiological risks and extents. Dynamic physiological activities are such a key metric that they are perceived by means of measuring galvanic skin response (GSR). GSR represents impedance of human skin that frequently changes based on different human respiratory and physical instability. Existing solutions, paved in literature and market, focus on the direct measurement of GSR by two sensor-attached leads, which are then parameterized against the standard printed circuit board mechanism. This process is sometimes cumbersome to use, resulting in lower user experience provisioning and adaptability in livelihood activities. The purpose of this study is to validate the novel development of the cost-effective GSR sensing system for affective usage for smart e-healthcare. Design/methodology/approach This paper proposes to design and develop a flexible circuit strip, populated with essential circuitry assemblies, to assess and monitor the level of GSR. Ordinarily, this flexible system would be worn on the back palm of the hand where two leads would contact two sensor strips worn on the first finger. Findings The system was developed on top of Pyralux. Initial goals of this work are to design and validate a flexible film-based GSR system to detect an individual’s level of human physiological activities by acquiring, amplifying and processing GSR data. The measured GSR value is visualized “24 × 7” on a Bluetooth-enabled smartphone via a pre-incorporated application. Conclusion: The proposed sensor-system is capable of raising the qualities such as adaptability, user experience, portability and ubiquity for possible application of monitoring of human psychodynamics in a more cost-effective way, i.e. less than US$50. Practical implications Several novel attributes are envisaged in the development process of the GSR system that made it different from and unique as compared to the existing alternatives. The attributes are as follows: (i) use of reproductive sensor-system fabrication process, (ii) use of flexible-substrate for hosting the system as proof of concept, (iii) use of miniaturized microcontroller, i.e. ATTiny85, (iv) deployment of energy-efficient passive electrical circuitry for noise filtering, (v) possible use case scenario of using CR2032 coin battery for provisioning powering up the system, (vi) provision of incorporation of internet of things (IoT)-cloud integration in existing version while fixing related APIs and (vii) incorporation of heterogeneous software-based solutions to validate and monitor the GSR output such as MakerPlot, Arduino IDE, Fritzing and MIT App Inventor 2. Originality/value This paper is a revised version R1 of the earlier reviewed paper. The proposed paper provides novel knowledge about the flexible sensor system development for GSR monitoring under IoT-based environment for smart e-healthcare.


2015 ◽  
Vol 27 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Ling Chunxian Zou ◽  
Chris Hunt

Purpose – This paper aims to describe the development of an approach that uses a flexible substrate to investigate the mechanism of conductive anodic filament (CAF) growth and effect of different material and manufacturing variables. Design/methodology/approach – A new approach using a simulated test vehicle (STV) has been developed to study the CAF phenomena. The STV can be easily built under controlled conditions in the laboratory using different glass fibres and resin powder to investigate the effect of different variables separately on CAF. The advantage of the STV is that CAF can be formed in relatively short period in a controlled way, and CAF growth can be easily identified using a back-lighting under a microscope due to the thin flex material used as the test sample. Findings – STV has been used to investigate a number of effects on CAF formation: different glass fibres, reflow process, acid contamination in drilled holes, desmear process and glass bundle size. The results demonstrate that for finished fibres acid contamination (plating solution) at the electrode was necessary for CAF formation. However, for unfinished glass fibres (loom state and heat cleaned) CAF can be formed without acid contamination. The reflow process significantly increases CAF formation. Running an aggressive desmear process and using large glass fibre bundle also increased CAF formation. Originality/value – This new approach will be of benefit for printed circuit board (PCB) supplier to evaluate CAF performance on different resin systems and glass fibres to provide high CAF resistance quality PCBs. The test period (168 hours) would be much shorter than the traditional CAF testing (1,000 hours).


2012 ◽  
Vol 463-464 ◽  
pp. 1368-1372
Author(s):  
Jiang Zhong Hang ◽  
Yin Yin Cheng ◽  
Jie Li ◽  
Li Yi Shi ◽  
Mei Hong Zhang

In this paper an UV-curable character ink with high dispersion and stability was prepared based on acrylic resin, acrylic monomer, photo-initiator, pigment and other additives. The viscosity, particle size and surface tension of the ink were 18~22mPas, 310~330 nm and 22~25 mNm-1 at 25oC, respectively. These features showed the possibility to inkjet printing the ink on printed circuit board (PCB). Inkjet printing with high resolution can be achieved by varying the dried droplet diameter. Applied voltage and temperature during the jetting process influenced the diameter of dried droplet.


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