scholarly journals Development of a Wireless Mesh Sensing System with High-Sensitivity LiNbO3 Vibration Sensors for Robotic Arm Monitoring

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 507 ◽  
Author(s):  
Yi-Chun Du ◽  
David Lin ◽  
Chun-Ping Jen ◽  
Choon Ng ◽  
Chi-Ying Chang ◽  
...  
Keyword(s):  
Transmission Rate ◽  
Low Cost ◽  
Rapid Development ◽  
High Sensitivity ◽  
Piezoelectric Sensor ◽  
Vibration Sensor ◽  
Mesh Network ◽  
Robotic Arm ◽  
Vibration Sensors ◽  
Wireless Mesh

In recent years, multi-axis robots are indispensable in automated factories due to the rapid development of Industry 4.0. Many related processes were required to have the increasing demand for accuracy, reproducibility, and abnormal detection. The monitoring function and immediate feedback for correction is more and more important. This present study integrated a highly sensitive lithium niobate (LiNbO3) vibration sensor as a sensor node (SN) and architecture of wireless mesh network (WMN) to develop a monitoring system (MS) for the robotic arm. The advantages of the thin-film LiNbO3 piezoelectric sensor were low-cost, high-sensitivity and good electrical compatibility. The experimental results obtained from the vibration platform show that the sensitivity achieved 50 mV/g and the reaction time within 1 ms. The results of on-site testing indicated that the SN could be configured on the relevant equipment quickly and detect the abnormal vibration in specific equipment effectively. Each SN could be used more than 10 h at the 80 Hz transmission rate under WMN architecture and the loss rate of transmission was less than 0.01% within 20 m.

scholarly journals Transparent and Flexible Vibration Sensor Based on a Wheel-Shaped Hybrid Thin Membrane

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1246
Author(s):  
Siyoung Lee ◽  
Eun Kwang Lee ◽  
Eunho Lee ◽  
Geun Yeol Bae
Keyword(s):  
Frequency Response ◽  
High Sensitivity ◽  
Vibration Sensor ◽  
Human Machine Interaction ◽  
High Transparency ◽  
Vibration Sensors ◽  
Low Stiffness ◽  
Machine Interaction ◽  
The Internet Of Things ◽  
Ultrathin Membranes

With the advent of human–machine interaction and the Internet of Things, wearable and flexible vibration sensors have been developed to detect human voices and surrounding vibrations transmitted to humans. However, previous wearable vibration sensors have limitations in the sensing performance, such as frequency response, linearity of sensitivity, and esthetics. In this study, a transparent and flexible vibration sensor was developed by incorporating organic/inorganic hybrid materials into ultrathin membranes. The sensor exhibited a linear and high sensitivity (20 mV/g) and a flat frequency response (80–3000 Hz), which are attributed to the wheel-shaped capacitive diaphragm structure fabricated by exploiting the high processability and low stiffness of the organic material SU-8 and the high conductivity of the inorganic material ITO. The sensor also has sufficient esthetics as a wearable device because of the high transparency of SU-8 and ITO. In addition, the temperature of the post-annealing process after ITO sputtering was optimized for the high transparency and conductivity. The fabricated sensor showed significant potential for use in transparent healthcare devices to monitor the vibrations transmitted from hand-held vibration tools and in a skin-attachable vocal sensor.

Wireless mesh network data communications and reliability analysis for anti-theft application deployment in educational institutions

2019 ◽  
Vol 17 (3) ◽  
pp. 474-489
Author(s):  
Roger van Rensburg ◽  
Bruce Mellado ◽  
Cesar Augusto Marin Tobon
Keyword(s):  
South Africa ◽  
Mesh Networks ◽  
Low Cost ◽  
Mesh Network ◽  
Educational Institutions ◽  
Data Communications ◽  
Wireless Technology ◽  
Content Type ◽  
Wireless Mesh

Purpose The purpose of this study is to locally develop low-cost wireless mesh networks for reliable data communications to devices that prevent the theft of these devices in learning institutions of South Africa. Design/methodology/approach A network test-bench was developed where millions of packets were transmitted and logged between interconnected nodes to analyze the quality of the network’s service in a harsh indoor building environment. Similar methodologies in “big data” analysis as found in particle physics were adopted to analyze the network’s performance and reliability. Findings The results from statistical analysis reveal the quality of service between multiple asynchronous transmitting nodes in the network and compared with the wireless technology routing protocol to assess coverage in large geographical areas. The mesh network provides stable data communications between nodes with the exception of reliability degradation in some multi-hopping routes. Conclusions are presented to determine whether the underlining mesh network technology will be deployed to protect devices against theft in educational institutions of South Africa. Research limitations/implications The anti-theft application will focus on proprietary firmware development with a reputable tablet manufacturer to render the device inoperable. Data communications of devices to the network will be monitored and controlled from a central management system. The electronics embedding the system-on-chip will be redesigned and developed using the guidelines stipulated by the chip manufacturer. Originality/value Design and development of low-cost wireless mesh networks to protect tablets against theft in institutions of digitized learning. The work presents performance and reliability metrics of a low-power wireless mesh wireless technology developed in a harsh indoor building environment.

Wireless mesh networks

2008 ◽  
Vol 14 (8) ◽  
pp. 401-403 ◽  
Author(s):  
Xinheng Wang
Keyword(s):  
Wireless Networks ◽  
Large Scale ◽  
Ad Hoc ◽  
Mesh Networks ◽  
Low Cost ◽  
Mesh Network ◽  
Self Healing ◽  
Large Area ◽  
Satellite Systems ◽  
Wireless Mesh

Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed.

A high-resolution electric field sensor based on piezoelectric bimorph composite

2021 ◽  
Author(s):  
Miaomiao Cheng ◽  
Jingen Wu ◽  
mengmeng Guan ◽  
Qi Mao ◽  
dan Xian ◽  
...  
Keyword(s):  
High Resolution ◽  
Electric Field ◽  
Electric Fields ◽  
Low Cost ◽  
Rapid Development ◽  
High Sensitivity ◽  
Pdms Layer ◽  
Electric Field Sensor ◽  
Power Frequency ◽  
Field Sensor

Abstract The rapid development of the internet of things (IOT) technology has led to great demand for intelligent electric field sensor (EFS). Several working principles have been proposed, however major challenges remain existed for the requirements of EFS with low-cost, large-range, and high-resolution. In this paper, an EFS based on piezoelectric bending effect using d31 mode is developed, where a bending strain is induced on the sandwiched bimorph structure of PZT/PDMS/PZT under an applied electric field, and the capacitance value of the PDMS layer reveals detectable variation. We demonstrate an electric field sensor operating at the stress-mediated coupling between piezoelectric ceramic and elastic dielectric polymer, which reveals advantages such as simple fabrication process, low-cost and low power consumption. Due to the sandwiched bimorph structure, the strain caused by the electric field can be effectively transferred to improve the resolution of the device. The constitutive equations for the sandwiched bimorph structure are built, and the working principle of the proposed EFS is demonstrated. The EFS exhibits high sensitivity under both AC and DC electric fields, with a resolution of 0.1V/cm in the range of -3 to 3kV/cm. The proposed sensor provides an alternative solution for power equipment fault diagnosis, power frequency electric field detection, etc.

scholarly journals Smart Seismocardiography: A Machine Learning Approach for Automatic Data Processing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Omar Y. López-Rico ◽  
Roberto G. Ramírez-Chavarría
Keyword(s):  
Heart Rate ◽  
Data Processing ◽  
Clustering Algorithm ◽  
Low Cost ◽  
Piezoelectric Sensor ◽  
Signal Spectrum ◽  
Automatic Data ◽  
Vibration Sensors ◽  
Custom Made ◽  
Invasive Method

Seismocardiography (SCG) is a non-invasive method that measures local vibrations created by the mechanical cardiovascular exercises on the chest wall. Thereby, mechanical movements of the heart are recorded in real-time from vibration sensors positioned on the chest of the subject, to further compute the heart rate and retrieve the SCG waveform. Although such events have been widely studied, robust signal processing methods remain a challenging task. On the other hand, the use of piezoelectric sensors has been favored in recent years due to its features and low cost. However, robust data processing techniques should be developed to increase their performance and reliability. In this work, we propose an attractive method for SCG data processing based on the K-Means clustering algorithm to automatically label waveform events. Interestingly, the SCG signals are recovered from a custom-made device built around an ultra-low-cost piezoelectric sensor. Once the signals are measured, they are pre-processed by spectral filtering. Afterwards, the signal spectrum is used to compute the heart rate (HR). Thereby, the filtered signal is sequentially segmented, and every frame is processed by a light-weight K-Means algorithm. Finally, we show the performance of the smart seismocardiography by analyzing SCG waveforms at different physiological conditions.

scholarly journals Low-cost wireless mesh communications based on openWRT and voice over internet protocol

2021 ◽  
Vol 11 (6) ◽  
pp. 5119
Author(s):  
Nina Siti Aminah ◽  
Muhamamad Reza Ramadhani Raharjo ◽  
Maman Budiman
Keyword(s):  
Low Cost ◽  
Internet Protocol ◽  
Session Initiation Protocol ◽  
Mesh Network ◽  
Line Of Sight ◽  
Voice Over Internet Protocol ◽  
Remote Areas ◽  
Wireless Mesh ◽  
Set Up ◽  
Non Line Of Sight

Technology makes it easier for us to communicate over a distance. However, there are still many remote areas that find it difficult to communicate. This is due to the fact that communication infrastructure in some areas is expensive to build while the profit will be low. This paper proposes to combine voice over internet protocol (VoIP) over mesh network implemented on openWRT router. The routers are performing mesh functions. We set up a VoIP server on a router and enabled session initiation protocol (SIP) clients on other routers. Therefore, we only need routers as a means of communication. The experiment showed very good results, in the line-of-sight (LOS) condition, they are limited to reception distances up to 145 meters while in the non-line-of-sight (NLOS) condition, they are limited to reception distances up to 55 meters.

scholarly journals Integrated routing system for wireless mesh networks

2021 ◽  
Author(s):  
Amir Esmailpour
Keyword(s):  
Network Performance ◽  
Ad Hoc ◽  
Mesh Networks ◽  
Low Cost ◽  
Access Network ◽  
Mesh Network ◽  
Mobile Nodes ◽  
Backbone Network ◽  
Wireless Mesh ◽  
Alternative Path

Recently Wireless Mesh Network (WMN) has become popular especially for its low cost deployment in the areas of poor network infrastructure and terrain of difficult deployment. Although paths in WMN backbone network are stable, the access link contention can severely constrain the end-to-end throughput. We proposed an integrated routing system for WMN that exploits both paths through the backbone network and through the ad-hoc access network of mobile nodes. The ad-hoc path is considered as an alternative path and is used only when the primary backbone path is severely constrained due to access links contention. We have shown through simulation that alternative path is effective in delivering higher throughput in that situation. We also proposed a scheme for initiating the route discovery of the ad-hoc path. The main contributions of this thesis are two algorithms that allow the mobile node to evaluate the throughput of the backbone and ad-hoc paths, and to make a decision of taking one path. The proposed algorithms are implemented in OPNET simulator, and network performance is studied under variety of conditions.

Classification of Channel Allocation Schemes in Wireless Mesh Network

2019 ◽  
pp. 65-92
Author(s):  
Abira Banik ◽  
Abhishek Majumder
Keyword(s):  
Channel Assignment ◽  
Wireless Mesh Network ◽  
Ad Hoc ◽  
Channel Allocation ◽  
Low Cost ◽  
Mesh Network ◽  
Available Bandwidth ◽  
Factors Affecting ◽  
Mesh Topology ◽  
Wireless Mesh

Wireless mesh network (WMN) is a widely accepted network topology due to its implementation convenience, low cost nature, and immense adaptability in real-time scenarios. The components of the network are gateways, mesh routers, access points, and end users. The components in mesh topology have a dedicated line of communication with a half-duplex radio. The wireless mesh network is basically implemented in IEEE 802.11 standard, and it is typically ad-hoc in nature. The advantageous nature of WMN leads to its extensive use in today's world. WMN's overall performance has been increased by incorporating the concept of multi-channel multi-radio. This gives rise to the problem of channel assignment for maximum utilization of the available bandwidth. In this chapter, the factors affecting the channel assignment process have been presented. Categorizations of the channel assignment techniques are also illustrated. Channel assignment techniques have also been compared.

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