Com o aumento das aplicações e dispositivos para Internet das Coisas, muitos esforços para reduzir potência dissipada nos transceptores foram investidos. A maioria deles, entretanto, focam individualmente no rádio, nos conversores analógicos para digital e viceversa, e na arquitetura de banda base digital. Como consequência, há pouca margem para melhorias na potência dissipada nestes blocos isolados que compense o enorme esforço. Portanto, este trabalho propõe uma arquitetura adaptativa a nível de sistema focando em reduzir o consumo no conversor analógico para digital e no receptor digital. Ele utiliza um algoritmo robusto para o receptor banda base digital, um conversor analógico para digital topologia Sigma-Delta e um bloco de controle realimentado conforme a relação sinal ruído medida do pacote recebido. O sistema foi projetado para o protocolo IEEE 802.15.4. Para validação do sistema e estimar a potência consumida foi feito um modelo de sistema utilizando a ferramenta Matlab, uma descrição do hardware em linguagem Verilog e uma síntese lógica utilizando o processo da X-FAB XC018. As simulações mostram uma redução na potência consumida pelo sistema de até 13% e ainda atingindo os requisitos do protocolo. Os resultados deste trabalho foram publicados na conferência internacional em tecnologia de instrumentação e medidas de 2014 realizada na cidade de Montevidéu no Uruguai. / With the increase of Internet of Things applications and devices, many efforts to reduce power consumption in transceiver has been invested. Most of them targeted in RF frontend, converters, or in the digital baseband architecture individually. As result, there are few margins nowadays for power improvement in these blocks singly that compensates the huge hard work required. The next optimization step leads to a system level analysis seeking design space and new possibilities expansion. It is in this field that adaptive systems approaches are conquering ground recently. The solutions combines Radio Frequency (RF) and process variation techniques, Low Pass Filters (LPF) and Analog to Digital Converters (ADCs) adjustment for better performance, digital baseband bit width adaptive according to income packet SNR, configurable ADC resolution and topology, and others. In this scenario the current work proposes an adaptive system level architecture targeting ADC and digital receiver power reduction. It uses a robust algorithm for digital baseband receiver, a Sigma-Delta ADC, and suggests a feedback control block based on packet SNR measure. The system was designed for the IEEE 802.15.4 standard and required system modeling using Matlab tool, hardware description in Verilog language, and logic synthesis using X-FAB XC018 process for validation and power consumption estimation. Simulations show up to 15% of system power reduction and still meeting the standard requirements. The work results were published in the International Instrumentation and Measurement Technology Conference of 2014 occurred in Montevideo - Uruguay.

Made available in DSpace on 2014-06-12T17:35:16Z (GMT). No. of bitstreams: 2 arquivo2009_1.pdf: 3503480 bytes, checksum: 85d90aa1952ca122f373c0f061692038 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O padrão zigbee foi utilizado na instrumentação de molas helicoidais de Ti-Ni utilizando, assim, a porta USB para comunicação de dados sem fio com o laptop e a mola utilizando a plataforma operacional Linux. Um estudo do comportamento da tensão elétrica da mola Ti-Ni sob a variação da corrente elétrica e distensão mecânica foi feito. Foi observado que para condições normais de temperatura e ambiente, o sistema apresentou variação linear na faixa analisada. E que uma análise estatística para uma faixa de operação de corrente e comprimentos constantes, a mola apresentou condições suficientes para a instrumentação. Foram desenvolvidos programas para que as tecnologias zigbee, microcontrolador, PIC16F877A e USB pudessem se comunicar entre si. A implementação do algoritmo sugerido mostrou-se, ao longo dos testes, um desempenho positivo. Uma análise do erro que o sistema de instrumentação sem fio poderia introduzir no monitoramento foi feita. Com isso, constatou-se que o erro absoluto do mesmo não apresentou nenhuma influência no monitoramento da distensão mecânica da mola. Os resultados mostraram-se favoráveis ao objetivo da dissertação e foi verificado que o monitoramento sem fio de distensão mecânica da mola Ti-Ni apresentou confiabilidade considerável

Sintetizadores de Freqüências são circuitos que geram sinais em freqüências pré-determinadas, sendo estes sinais usados tanto na recepção como na transmissão de Rádio Freqüência. Os circuitos Sintetizadores possuem diversos blocos, dentre os quais podemos citar, osciladores controlados por tensão (VCO Voltage-Controlled Oscillator), divisores programáveis (Prescaler), comparadores de fase (DFF Detectores de Fase e Freqüência), bombas de carga (CP Charge Pump) e Filtros Passa Baixas (LPF Low Pass Filters). Em 2003 foi projetado por Angel M.G. Argüello [Ar04] um circuito Sintetizador de Freqüências com arquitetura tipo Integer-N. Este circuito, projetado para ter banda centrada em torno de 2,4 GHz e 16 canais de 4,78 MHz, foi implementado na tecnologia CMOS 0,35 µm da AMS (Austrian Micro Systems), que possui quatro níveis de metais e dois níveis de polisilício. Após testes do circuito as seguintes conclusões sobre seu funcionamento foram derivadas: o circuito funcionou qualitativamente como projetado, sintetizando 16 tons de freqüência; o ruído de fase medido ficou acima do valor desejado; a potência consumida esteve dentro dos valores previstos, porém elevada. No decorrer de 2004 foram feitas alterações no layout do circuito de Argüello com o objetivo de melhorar o ruído de fase. Estas alterações serviram como estudo preliminar para este trabalho. Dando continuidade ao desenvolvimento de Sintetizadores, em 2005 foram estudadas novas estruturas e layouts mais eficientes no tocante a ruído de fase, dando-se especial atenção às alimentações dos circuitos digitais e analógicos e ao isolamento entre os mesmos. Um novo circuito Sintetizador foi desenvolvido para aplicações em sistemas ZigBee, que operam na banda de freqüência entre 2,400 GHz a 2,485 GHz, com 16 canais de largura igual 2 à 5 MHz. Resultados de simulação sobre o circuito projetado apontaram o funcionamento adequado, com consumo de potência inferior a 32 mW para tensão de alimentação de 3,3 V. / Frequency Synthesizers are circuits that generate pre-determined frequencies, used in both radio frequency reception and transmission. The Synthesizer circuits are composed by several blocks, such as Voltage-Controlled Oscillator (VCO), Prescaler, PFD (Phase/Frequency Detector), Charge Pump (CP), and Low Pass Filters (LPF). In 2003, an Integer-N architecture Frequency Synthesizer circuit was developed by Angel M.G. Argüello [Ar04]. This circuit, designed to have a band centered around 2.4 GHz and 16 channels with a 4.78 MHz, were implemented with the 0.35 µm CMOS technology from AMS (Austrian Micro Systems), using four metal levels and two polisilicon levels. After the circuit tests, the following conclusions about its operation were derived: the designed circuit operated as expected, generating 16 tons of frequency; the phase noise stayed above of the desired value; the power consumption were within the expected values although high. During the year of 2004, several modifications in the Argüello circuit layout have been done in order to improve the phase noise. These modifications were a preliminary study to this work. Advancing in the development of Synthesizers, in 2005 new structures and more efficient layouts, in terms of noise, were studied, with special attention given to the digital and analog power supplies and their isolation. A new Synthesizer was developed for applications with the ZigBee, which operates with frequencies from 2.400 GHz to 2.485 GHz and 16 channels of 5 MHz. The simulation results pointed out the correct operation of the circuit, with power consumption lower than 32 mW for power supply of 3.3 V.

Orientadores: Francisco José Arnold, Leonardo Lorenzo Bravo Roger / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-19T02:17:11Z (GMT). No. of bitstreams: 1 Roccia_ClerivaldoJose_M.pdf: 1742155 bytes, checksum: fd0bcca80aa7a8e8592cfb08b248712e (MD5) Previous issue date: 2011 / Resumo: Redes de Sensores Sem Fio (RSSFs) são utilizadas, normalmente, em ambientes de difícil acesso tais como vulcões, florestas, caldeiras, agricultura de precisão e gasodutos. As unidades fundamentais dessas redes são os nós sensores que trocam informações e dados usando tecnologia sem fio. Como em qualquer tipo de rede de comunicação, podem ocorrer falhas que prejudiquem a operação da RSSF. Por essa razão, é necessário avaliar as métricas de desempenho da rede para que se estabeleçam condições para instalação das mesmas em ambientes específicos. Este trabalho apresenta a avaliação de uma RSSF, baseada na plataforma IRIS, desenvolvida pela Universidade de Berkeley e distribuída comercialmente pela empresa Crossbow Technology Inc, operando no modo de Requisição Resposta (RR) em quatro cenários distintos: campo aberto e cultivos agrícolas de milho, de pinhão e de eucalipto. Esta avaliação tem o objetivo de estabelecer distâncias máximas de separação entre os nós em cada ambiente, mas conservando as condições de operacionalidade da RSSF. O desempenho da rede nestes cenários foi avaliado através das métricas de perda de pacotes, tempo de resposta, consumo de baterias, utilização de largura de banda, consumo de memória e intensidade do sinal de rádio no receptor (RSSI). Nos experimentos foi encontrado que a distância máxima de separação entre os nós na cultura de milho deve ser de 16m, enquanto no pinhão e no eucalipto são de 25,5m e 46m, respectivamente. Os resultados permitem concluir que a densidade da vegetação entre os nós afeta o desempenho das RSSFs / Abstract: Wireless Sensor Networks (WSNs) are used in tough environments such as volcanoes, forests, boilers, agriculture precision and pipelines. The fundamental units of these networks are sensor nodes that exchange information and data using wireless technology. As with any type of network communication, faults can occur that jeopardize the operation of the WSN. For this reason, it is necessary to evaluate the network performance metrics for aiming to establish conditions for network installation in specific environments. This work presents the evaluation of a WSN-based IRIS platform developed by UC Berkeley and distributed commercially by Crossbow Technology Inc. operating in the Request for Response (RR) mode in four different scenarios: an open field and the other scenarios crops of corn, pine nuts and eucalyptus. The network performance in these scenarios was evaluated by metrics such as packet loss, response time, consumption battery, bandwidth, memory consumption and intensity of radio signal receiver (RSSI). In the experiments it was found that the maximum distance separating the nodes in the corn should be 16m, while in pine and eucalyptus were 25,5m and 46m, respectively. The results lead to the conclusion that the density of vegetation between the nodes affects the performance of WSNs / Mestrado / Tecnologia e Inovação / Mestre em Tecnologia

The goal of the Internet of Things’ sensing technology is to provide LBS(location-based services); a key technology is finding out how to positioning the sensing devices. For positioning outdoors, mature tech-nology such as GPS and cellular network location can be used. There is little research about indoor positioning, and there is no finished product on the market. This paper shows how to use both Wi-Fi and ZigBee signal for position-ing; Wi-Fi to find the area position and ZigBee to find the coordinate position. The main contribution of this paper is described in the follow-ing: This paper will present an algorithm using kNN on a Wi-Fi signal, as a way to find the location area of users. The GPS signal cannot be used indoors, but there are usually numerous Wi-Fi signals, that can be used for indoor positioning. In this design, to build a dataset containing the number of locations and the Wi-Fi signal strength list of each location. When indoor positioning is needed, the KNN algorithm is used to compare the user’s Wi-Fi signal strength with the dataset and find the location number. When precise positioning is needed, the ZigBee signal should be used. In this paper two different methods for precise positioning in are used, one is an improved algorithm of triangle centroid algorithm where the positioning accuracy depends on the number of anchor points and the interval of each point. The other method is the neural network method. This method could give stable result with only four anchor points. Finally, there is a comparison of the methods mentioned in this paper : the Wi-Fi fingerprint method, the ZigBee triangle centroid algorithm, and neural network method.

Context. Localization and positioning services are nowadays very extended and the growth is still continuing. Many places already provide wireless tracking systems to monitor the people or material movements, specially indoors. The new arising ZigBee wireless technology provides an efficient network management and a low battery consumption, making it appropriate for location purposes in portable devices like mobile phones. Objectives. The aim is to locate a ZigBee device located inside a golf ball that has been lost within an outdoors area. An Android phone connected to a ZigBee device via USB will serve as coordinator of the localization network and by giving on-screen instructions and guidance provided by the conceptual Decision Support System (DSS). Methods. The measurement used in the localization process is the Received Signal Strength (RSS). With this data, the distance between the sensors can be estimated. However to obtain an accurate position several readings from different sensors might be needed. This paper tests the precision levels of the ZigBee modules varying the number of sensors in the localization network and using the triangulation method. Results. The precision is the main variable measured in the results, which reaches distance variation of less than 1 meter in cases where the triangulation approach can be applied. For the localization process, the use of less than three sensors lead to very poor results, obtaining a wrong localization in around 30\% of the cases. Also, movement patterns were discovered to improve the localization process. All this data can be used as an input for the DSS for future improvements. Conclusions. This study proves that outdoor positioning with ZigBee devices is possible if the required level of precision is not very high. However, more studies concerning localization with less than three sensors have to be conducted to try to reach the goal of one-on-one localization. This study opens the door for further investigations in this matter.

Den här C-uppsatsens mål är att undersöka om den trådlösa tekniken ZigBee är lämplig att använda i en industriell miljö. Arbetet med uppsatsen har utförts i Trolhättan (Sverige) i företaget Binar Elektronik AB:s lokaler. Bakgrunden till detta samarbete är att Binar vill veta om ZigBee är ett lämpligt val för en av deras framtida produkter. Uppsatsen är uppdelad i fyra delar, där den första och inledande delen översiktligt beskriver begreppet ZigBee. Den här delen innehåller även en marknadsundersökning rörande ZigBee-hårdvara. Uppsatsen fortsätter sedan med nästa del där en specialisering mot en specifik ZigBee-hårdvara tar vid. Den ZigBee-modul som valdes kallas Xbee och den blev utvald baserat på resultatet från marknadsundersökningen. Den här delen beskriver även den kod som utvecklats för att på ett effektivt sätt kommunicera med Xbee-modulen. Uppsatsens tredje del består av ett antal praktiska tester i olika miljöer, vars mål är att påvisa vilka styrkor och svagheter som ZigBee-tekniken har i respektive miljö. Den här delen innehåller även ett räckviddstest av Xbee-modulen. Den sista och avslutande delen innehåller uppsatsens resultat och slutsatser. Dessa slutsatser visar tydlig att Xbee-modulen, och dess ZigBee-tekniken, har stor potential att uppfylla de krav som ställs på ett trådlöst system i en industriell miljö. Det måste dock noteras att denna slutsats ej bör tas ur sitt sammanhang och att den således endast är giltig för de testmiljöer som den här uppsatsen behandlat. / This Bachelor of Science thesis has the primary objective to investigate whether or not the wireless technology ZigBee is suitable for industry usage. The thesis work has been done in collaboration with Binar Elektronik AB (Trollhättan, Sweden). The background story for this collaboration is that Binar is interested in finding out if ZigBee is suitable for one of their upcoming products. The thesis is divided into four main parts, beginning with a researching part concerning ZigBee as a concept and a market research on ZigBee hardware. The thesis continuous with a specialization towards one ZigBee hardware, the ZigBee module from MaxStream called Xbee. The Xbee module was chosen based on the result from the market research. This part also describes the code that has been developed for the Xbee module, which main purpose is to simplify communication with the module. The next part of the thesis contains a number of different field tests that show how ZigBee communication is affected in different environments. This part also includes a range test with the Xbee module. The last part of the thesis contains the final results and conclusions, which clearly show that the ZigBee technology, and Xbee in particular, has a potential to satisfy the requirements for a wireless system in an industrial environment. This conclusion concerning the industrial usability of ZigBee should however be seen in the light of this particular thesis work, making this conclusion viable only for the field test environments. / See hompage http://www.wettergren.se/zigbee/.

Autorizada por el autor, pero con restricción para ser publicada a texto completo hasta el año 2015 / Esta memoria de título se enmarca en un proyecto que busca ofrecer una solución completa de monitoreo remoto. El control está enfocado en distintos dispositivos de medición en el rubro minero. El objetivo general consiste en el desarrollo de un punto de acceso, el cual permite la integración de una red de sensores con diferentes tecnologías de comunicaciones inalámbricas, tales como telefonía celular u otras compatibles con el protocolo TCP/IP. El sistema electrónico desarrollado adquiere la información desde una malla de sensores. Se utiliza un microcontrolador que procesa los datos de acuerdo a cada modo de funcionamiento. El objetivo es enviar la información de manera serial a un módem GSM/GPRS, en el caso de comunicación con la red de celular, o directamente a un conversor TCP/IP para tecnologías que utilizan este protocolo. Otra importante función del circuito integrado es configurar y controlar el punto de acceso, posibilitando automatizar el diseño realizado. El resultado es un producto que permite enviar datos desde los sensores de medición, hacia una red de telefonía celular o con destino de alguna tecnología basada en el protocolo TCP/IP. El prototipo implementado se caracteriza por ser escalable de acuerdo a los requerimientos del usuario, resolviendo una necesidad de la industria minera. Se concluye que es factible transmitir la información adquirida en distintos dispositivos, ubicados en diferentes zonas de una faena, de manera confiable y con una baja inversión. La empresa patrocinante de esta memoria ha manifestado su interés en comercializarlo, al ser un desarrollo que no tiene símil en el mercado. El trabajo futuro de esta implementación es poner en funcionamiento un sistema de respaldo para los datos, en momentos que se pierda conexión con la red de celular.

This master´s thesis is dealing with designing wireless management system for existing buildings. In the first part there is description of topologies a communication protocols used for wireless automation. Further there are characterized some devices for lighting, heating, ventilation and cooling regulation. These are used for a model network of a building management, where is system OpenHAB also presented. In the next chapter is aprissed specific edifice and its typical operation where is also designed basic and extended solution for it. This part continues with computation of energy consumption in TRNSYS software, that are used to calculate economic return for both variants.

This diploma thesis describes practical realization of entrance terminal, which enables transmission of data thanks to radio module ZigBee PAN4551 and Ethernet module Rabbit RCM3200. This entrance system uses Mifare RFID cards, with whose user will identify at the entrance terminal of the guarded object. Data are sent to server station by radio module ZigBee or Ethernet module Rabbit during demand of entrance. The database of all entrance rights of all users is stored on this server. Data system works up received data and sends them back to the terminal. One part of these data is the information about enabling of user entrance. The database system makes a list of passing through users. In the first part of this work whole conception of entrance terminal is suggested. Then basic demands of each block are described in details as well as their placement in guarded object. Next chapters describe basic function of terminal, electrical scheme, and system of power supplies for the access system. Also individual hardware components are chosen and described. In the on of the last chapter there is flow-process diagram of main loops for individual variants of terminal and interrupts functions from timer, serial link and external input from radio network MC13193 drawn. In the last chapter there is a show of server data application “AccessServer” and his basic description.