Commercial tactile sensors for hand exoskeletons: practical considerations for ultra-low cost and very-low complexity read-out

Photoplethysmography (PPG) is a common and practical technique to detect human activity and other physiological parameters and is commonly implemented in wearable devices. However, the PPG signal is often severely corrupted by motion artifacts. The aim of this paper is to address the human activity recognition (HAR) task directly on the device, implementing a recurrent neural network (RNN) in a low cost, low power microcontroller, ensuring the required performance in terms of accuracy and low complexity. To reach this goal, (i) we first develop an RNN, which integrates PPG and tri-axial accelerometer data, where these data can be used to compensate motion artifacts in PPG in order to accurately detect human activity; (ii) then, we port the RNN to an embedded device, Cloud-JAM L4, based on an STM32 microcontroller, optimizing it to maintain an accuracy of over 95% while requiring modest computational power and memory resources. The experimental results show that such a system can be effectively implemented on a constrained-resource system, allowing the design of a fully autonomous wearable embedded system for human activity recognition and logging.

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Low-cost 3-axis soft tactile sensors for the human-friendly robot Vizzy

2017 IEEE International Conference on Robotics and Automation (ICRA) ◽

10.1109/icra.2017.7989118 ◽

2017 ◽

Cited By ~ 29

Author(s):

Tiago Paulino ◽

Pedro Ribeiro ◽

Miguel Neto ◽

Susana Cardoso ◽

Alexander Schmitz ◽

...

Keyword(s):

Low Cost ◽

Tactile Sensors

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A low-cost, human-like, high-resolution, tactile sensor based on optical fibers and an image sensor

International Journal of Advanced Robotic Systems ◽

10.1177/1729881418783631 ◽

2018 ◽

Vol 15 (4) ◽

pp. 172988141878363 ◽

Cited By ~ 2

Author(s):

Utku Büyükşahin ◽

Ahmet Kırlı

Keyword(s):

High Resolution ◽

Spatial Resolution ◽

Fiber Optic ◽

Low Cost ◽

Experimental Studies ◽

Main Idea ◽

Tactile Sensor ◽

Image Sensor ◽

Sensor Design ◽

Tactile Sensors

Tactile sensors are commonly a coordinated group of receptors forming a matrix array meant to measure force or pressure similar to the human skin. Optic-based tactile sensors are flexible, sensitive, and fast; however, the human fingertip’s spatial resolution, which can be regarded as the desired spatial resolution, still could not be reached because of their bulky nature. This article proposes a novel and patented optic-based tactile sensor design, in which fiber optic cables are used to increase the number of sensory receptors per square centimeter. The proposed human-like high-resolution tactile sensor design is based on simple optics and image processing techniques, and it enables high spatial resolution and easy data acquisition at low cost. This design proposes using the change in the intesity of the light occured due to the deformation on contact/measurement surface. The main idea is using fiber optic cables as the afferents of the human physiology which can have 9 µm diameters for both delivering and receiving light beams. The variation of the light intensity enters sequent mathematical models as the input, then, the displacement, the force, and the pressure data are evaluated as the outputs. A prototype tactile sensor is manufactured with 1-mm spatial and 0.61-kPa pressure measurement resolution with 0–15.6 N/cm2 at 30 Hz sampling frequency. Experimental studies with different scenarios are conducted to demonstrate how this state-of-the-art design worked and to evaluate its performance. The overall accuracy of the first prototype, based on different scenarios, is calculated as 93%. This performance is regarded as promising for further developments and applications such as grasp control or haptics.

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Performance Optimization Based Spectrum Analysis on Optical Fiber Raman Amplifier with Backward Pumping

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.263-266.1004 ◽

2012 ◽

Vol 263-266 ◽

pp. 1004-1007 ◽

Cited By ~ 2

Author(s):

Li Ying Liu ◽

Yan Huang ◽

Chun Yu Liu ◽

Xin Ming Zhang ◽

Jiu Ru Yang

Keyword(s):

Optical Fiber ◽

Spectrum Analysis ◽

Performance Optimization ◽

Low Cost ◽

Low Complexity ◽

Gain Bandwidth ◽

Raman Amplifier ◽

Fiber Raman Amplifier ◽

Output Performance ◽

Output Characteristics

Optical fiber Raman amplifier (OFRA) with wide and flat gain bandwidth has been widely applied in the fields of optical communication, sensing and measurement. However, the performance optimization is always one of the hot topics in the study of OFRA, because its output characteristics are hardly dependent to some key designing parameters. In this paper, to overcome the problems above, we adopt a spectrum analysis based method to study the output performance of an OFRA system with backward pumping. By simulating the operation of the OFRA system, its output characteristics are first showed easily, with the advantages of real time, low cost, and low complexity. Further, according to the numerical results obtained, the optimal parameters of an OFRA system are determinate, and the performance in terms of output power, signal noise ratio, and the level of gain flatness is improved and optimized obviously.

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Low Complexity and Low-Cost Hardware Sharing Design of Fast Multistandard 2-D DCT/IDCT for Image/Video Coding

Research Journal of Information Technology ◽

10.3923/rjit.2014.27.45 ◽

2014 ◽

Vol 6 (1) ◽

pp. 27-45

Author(s):

Mohamed El Aakif ◽

Said Belkouch ◽

Moha M`rabet Ha

Keyword(s):

Video Coding ◽

Low Cost ◽

Low Complexity ◽

Hardware Sharing

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Layer Morphology and Ink Compatibility of Silver Nanoparticle Inkjet Inks for Near-Infrared Sintering

Nanomaterials ◽

10.3390/nano10050892 ◽

2020 ◽

Vol 10 (5) ◽

pp. 892

Author(s):

Dieter Reenaers ◽

Wouter Marchal ◽

Ianto Biesmans ◽

Philippe Nivelle ◽

Jan D’Haen ◽

...

Keyword(s):

Silver Nanoparticle ◽

High Speed ◽

Processing Time ◽

Near Infrared ◽

Printed Electronics ◽

Low Cost ◽

Low Complexity ◽

Post Processing ◽

Drop On Demand ◽

Processing Step

The field of printed electronics is rapidly evolving, producing low cost applications with enhanced performances with transparent, stretchable properties and higher reliability. Due to the versatility of printed electronics, industry can consider the implementation of electronics in a way which was never possible before. However, a post-processing step to achieve conductive structures—known as sintering—limits the production ease and speed of printed electronics. This study addresses the issues related to fast sintering without scarifying important properties such as conductivity and surface roughness. A drop-on-demand inkjet printer is employed to deposit silver nanoparticle-based inks. The post-processing time of these inks is reduced by replacing the conventional oven sintering procedure with the state-of-the-art method, named near-infrared sintering. By doing so, the post-processing time shortens from 30–60 min to 6–8 s. Furthermore, the maximum substrate temperature during sintering is reduced from 200 °C to 120 °C. Based on the results of this study, one can conclude that near-infrared sintering is a ready-to-industrialize post-processing method for the production of printed electronics, capable of sintering inks at high speed, low temperature and with low complexity. Furthermore, it becomes clear that ink optimization plays an important role in processing inkjet printable inks, especially after being near-infrared sintered.

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A System for the Detection of Persons in Intelligent Buildings Using Camera Systems—A Comparative Study

Sensors ◽

10.3390/s20123558 ◽

2020 ◽

Vol 20 (12) ◽

pp. 3558 ◽

Cited By ~ 1

Author(s):

Miroslav Schneider ◽

Zdenek Machacek ◽

Radek Martinek ◽

Jiri Koziorek ◽

Rene Jaros

Keyword(s):

Detection System ◽

Low Cost ◽

Low Complexity ◽

Recognition System ◽

Detection Methods ◽

Intelligent Building ◽

Dynamic Background ◽

Image Field ◽

Camera Systems ◽

Background Image

This article deals with the design and implementation of a prototype of an efficient Low-Cost, Low-Power, Low Complexity–hereinafter (L-CPC) an image recognition system for person detection. The developed and presented methods for processing, analyzing and recognition are designed exactly for inbuilt devices (e.g., motion sensor, identification of property and other specific applications), which will comply with the requirements of intelligent building technologies. The paper describes detection methods using a static background, where, during the search for people, the background image field being compared does not change, and a dynamic background, where the background image field is continually adjusted or complemented by objects merging into the background. The results are compared with the output of the Horn-Schunck algorithm applied using the principle of optical flow. The possible objects detected are subsequently stored and evaluated in the actual algorithm described. The detection results, using the change detection methods, are then evaluated using the Saaty method in order to determine the most successful configuration of the entire detection system. Each of the configurations used was also tested on a video sequence divided into a total of 12 story sections, in which the normal activities of people inside the intelligent building were simulated.

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