José A. Mendes

WECO: A wireless platform for monitoring recycling point spots

There is a growing demand for low cost, very low power and reduced size monitoring systems with wireless communications, to be used in different kinds of industrial environments. In several countries waste separation and recycling is a major issue. Consequently, the number of recycling spots has been steadily increasing. In order to ensure that recycle bins are properly maintained, several monitoring solutions have been proposed. These still have several limitations, such as requiring wires for power and/or communications and not being able to fit in all existing types of bins. This paper presents WECO, a wireless embedded solution for monitoring the level of the bins located in recycling spots. The proposed system automatically alerts a remote central station when a bin reaches a programmable filling level, thus avoiding the need to spot check if the bin is full and ensuring that the recycling spot is kept clean. The developed prototype required hardware-software co-design and aimed to meet the above mentioned requirements, resorting to the IEEE 802.15.4 protocol for wireless communications between all nodes in the network, each based on a System-On-Chip (SoC) CC2530 from Texas Instruments. Due to its wireless nature, the architecture requires a battery for power supplying the nodes, with a life time of at least six years. The filling level readings of each bin in a recycling spot is made using an ultrasonic sensor. The data collected by the monitoring platform is then sent to the remote central station that processes it in order to optimize routes and establish a scheduled collection of the recycling spots.

Nanogranular BaTiO3–CoFe2O4 thin films deposited by pulsed laser ablation

Detailed structural and magnetic measurements were performed on nanostructured composite thin films of cobalt ferrite (CoFe2O4-magnetostrictive) dispersed in a barium titanate (BaTiO3-piezoelectric) matrix, with different CoFe2O4 concentrations (ranging from x=20% to x=70%). The films were deposited by laser ablation on platinum covered Si(100). Their structure was studied by x-ray diffraction and Raman spectroscopy. The magnetic properties were measured with a superconducting quantum inteference device magnetometer. The nanocomposite films were polycrystalline and composed by a mixture of tetragonal-BaTiO3 and CoFe2O4 with the cubic spinel structure. The lattice parameter of the CoFe2O4 phase varied from 8.26A (x=20%) to 8.35A (x=70%), and, compared with bulk CoFe2O4, it was under compressive stress that relaxed as its concentration progressively increased. In the tetragonal-BaTiO3 phase, the lattice parameter a was contracted relative to the bulk phase and decreases with x. The lattice parameter c incre...

Sensors, Actuators and Communicators When Building a Ubiquitous Computing System

Ubiquitous computing systems are characterized by a collection of devices working together autonomically. Due to the fact that these systems are composed by a high number of devices, several problems arise. These problems range from management, compatibility to economic costs. In this paper some essential characteristics of sensors and actuators are proposed in order to allow them to be included in a ubiquitous computing system. It is also presented a way to build ubiquitous systems by integration of several independent systems, creating one system with new features that could not be found in the original ubiquitous systems.

An intelligent home automation control system based on a novel heat pump and Wireless Sensor Networks

One of technologys main goals is to providing comfort to humans. However, in order to be an aid, it has to be easy to install, use and maintain. The ever growing complexity of technological systems can only be achieved by converging different technologies. This is usually expressed as Cyber-Physical Systems (CPS), previews the symbiosis of several technologies in order to make them more accessible. This paper attempts to demonstrate the integration between two technologies such as: Heat-pump System and Wireless Sensor Network (WSN) to provide a new control mechanism for new building generations so-called smart houses. The proposed control architecture benefits from our developed WSN hardware platform. It enables the user to control and monitor the ventilation system using our developed mobile application and/or a personal computer. Also, the performance of the proposed hardware platform is measured in three different environments in order to observer the coverage area of the WSN.

Application of a Web-based monitoring and control system in plastic rotational moulding machine

This paper presents a Web based monitoring and control system. The system was applied to an industrial rotational moulding plastic oven. The developed system provides remote monitoring of several temperature sensors included in the oven, as well as control of the operation cycle in which the oven works. The oven is a rotational machine therefore no cables were able to be used, so it was necessary to use wireless technologies like radio frequency to achieve communication between the machine and the monitoring station. The system architecture and the developed software are presented in this paper.

Structural and Electrical Characterization of Lead Metaniobate Thin Films Deposited by Pulsed Laser Ablation

Lead niobate thin films have been prepared by laser ablation, at different substrate temperatures (T dep ) and with different oxygen pressures (pO 2 ). For low deposition temperatures the films presented a rhombohedric-PbNb 2 O 6 structural phase, with hysteresis cycles characteristic of a paraelectric. As T dep increased the films started to develop an orthorhombic-PbNb 2 O 6 structure that appeared at 400°C and remained up to 600°C. For low pO 2 , a mixture of this phase and a lead deficient phase was present in the films. Increasing the oxygen pressure the lead deficient phase was strongly reduced and the films presented only the ferroelectric orthorhombic-PbNb 2 O 6 structural phase.

Automatic velocity control in cutting-off machines

Usually, automatic cutting-off machines, of metallic pipes or bars, use constant cutting velocity. This mode of operation, constant cutting velocity combined with different profiles of materials to be cut, causes variable cutting forces to be applied to the saw. As a result, the cutting off machine is generally set for the worst expected conditions, otherwise excessive wear of the saw and machine will occur. Further, traditional cutting-off machines require adjustments to be made in order to automatically detect the completion of a cut. The objective of this project is the study of the application of control algorithms to the process of cutting-off metallic pipes or bars, with variable profiles, implemented in an industrial cutting-off machine, commercially available. The testes algorithms concern real-time cutting control and automatic detection of cut completion. The algorithms are implemented in a low cost programmable logic controller (PLC), allowing its adoption in industrial applications without significant increase on machine cost. All algorithms were developed having in mind safety issues relative to the operation of the cutting machine in order to prevent damage to the machine itself. Also, all process related relevant parameters are monitored on a personal computer using OPC (object linking and embedding-for process control).

A distributed system to automate labor-intensive industries and building supervision

The present paper describes a distributed system, which purpose is to control and manage the operation of different electrical and electronic systems and other equipment. The system was designed to be installed over already in place nonautomated devices, delivering all relevant data either to machine operators or managers; different formats are used in these messages, leading to a hierarchical control and supervision. The system was developed on industry demand, primarily to achieve building supervision and control. It allows real time control of different devices and systems as a simple intrusion detector to an, already in use, industrial network. Several intelligent controllers were developed and are presented. The system can have different topologies and interconnect, through gateways, to already installed networks. The different level algorithms used either at the PC or the controllers are described and discussed. We also present the work we are carrying out to allow the interconnection of the system to a WAN, allowing an authorized user to supervise the system.<<ETX>>

Survey and Taxonomy of Transmissions Power Control Mechanisms for Wireless Body Area Networks

Wireless body area networks (WBANs) comprise several sensor nodes equipped with a short range radio-frequency transceiver, implanted and/or attached to the human body. Their low form-factor and localization imply less resources available and limited energy capabilities. Therefore, energy efficiency of WBANs is a critical issue since, in many cases, batteries cannot be replaced or recharged, requiring mechanisms to extend their life-time. The aim of transmission power control (TPC) mechanisms, which can be combined with other energy-saving mechanisms, is to reduce the energy consumption, external interferences, and specific-observation-rate in wireless communications by dynamically adjusting the transmission power output of data transmission, with the minimum effect on other performance aspects, such as reliability and latency. This paper describes and analyzes the TPCs developed as a result of a synergy created by two mechanisms, a link quality estimator and the transmission power level control. Design choices, in terms of the solutions devised to each mechanism, as well as, the strategy adopted to combine them in a TPC, are highlighted. A comparison between the newest and the most relevant research works in this area is provided as a guideline to future research. A taxonomy to classify the different TPC mechanisms developed is proposed.

Energy saving mechanism for a smart wearable system: Monitoring infants during the sleep

In Smart Wearable Systems (SWS), the wearable devices are powered by batteries with very limited energy available. These emergent systems have strong Quality of Service (QoS) requirements, with focus on reliable communication and low power consumption. This is the scope of the Baby Night Watch, a project developed in the context of the European Texas Instruments Innovation Challenge (TIIC) 2015. This Project consists of a monitoring tool for infants, which matches different emergent research fields. SWSs require energy saving mechanism to reduce the energy wasting during wireless communications. A Transmission Power Control (TPC) mechanism that changes its characteristics according to the scenario of operation, is proposed. It uses sensors to determine the position of the infant and, based on that, predicts the current state of the channel. Other TPC algorithms are implemented and their performance are compared with our novel mechanism. The proposed TPC mechanism outperforms the existing ones in terms of the energy saving.