Submitted by FABRICIO MARQUI SANCHES null (fabriciosmf@yahoo.com.br) on 2016-01-05T12:05:05Z No. of bitstreams: 1 DISSERTAÇÃO-Fabricio_Marqui_Sanches.pdf: 2162339 bytes, checksum: 257059fa1be635fc6245b0168ddbebc4 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-01-06T17:34:12Z (GMT) No. of bitstreams: 1 sanches_fm_me_ilha.pdf: 2162339 bytes, checksum: 257059fa1be635fc6245b0168ddbebc4 (MD5) / Made available in DSpace on 2016-01-06T17:34:13Z (GMT). No. of bitstreams: 1 sanches_fm_me_ilha.pdf: 2162339 bytes, checksum: 257059fa1be635fc6245b0168ddbebc4 (MD5) Previous issue date: 2015-12-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho é investigada a viabilidade energética do emprego de buzzers piezelétricos, circuito retificador de onda completa e conversor DC-DC elevador em um sistemas de power harvesting submetido a esforços mecânicos causados pelo tráfego de veículos e/ou caminhar de pedestres, demonstrando a possibilidade de reutilização dessa energia no carregamento de baterias para alimentação de circuitos autônomos de monitoramento, indicação, iluminação, etc., em locais remotos, eliminando ou estendendo os intervalos necessário entre as recargas desses dispositivos. O gerador piezelétrico é analisado mediante a excitação realizada por um cilindro pneumático simulador de impactos controlado eletronicamente com frequência de 0,5 Hz e 1 Hz, contendo diferentes quantidades de PZTs (2, 4 e 8) e configuração de ligação (série ou paralelo). Os resultados extraídos são referentes à tensão elétrica, corrente, potência e energia armazenada em função do tempo, sendo ainda feitas relações dessas grandezas com diferentes números de PZTs, área que ocupam, força e pressão aplicada sobre os mesmos. Ao final pode-se concluir a viabilidade da utilização de dispositivos simples em sistemas de power harvesting para geração de energia através de excitações na forma pulsada e em baixas frequências, sendo os maiores valores na saída do circuito em termos de potência e corrente para tensão de 5 volts, 108 µW e 21,5 µA (0,53 Kg e 0,83 N/cm2), bem como 118,8 µW e 23,6 µA para (2,13 Kg e 3,33 N/cm2), obtidos com 8 PZTs, conectados em paralelo e excitados a 1 Hz. / This paper investigated the energy viability of the use of piezoelectric buzzers, rectifier circuit full-wave and DC-DC-converter in a power harvesting systems subjected to mechanical stress caused by the traffic of vehicles and / or walk for pedestrians, demonstrating the possibility of re-use of energy in charging batteries to power autonomous monitoring circuits, display, illumination, etc., in remote locations, eliminating or extending the intervals needed between charges these devices. The piezoelectric generator is analyzed through excitation carried out by a pneumatic cylinder simulator electronically controlled impacts with a frequency of 0.5 Hz and 1 Hz, containing different amounts of PZTs (2, 4, 8) and connection configuration (parallel or serial) . The extracted results are related to the voltage, current, power and energy stored in function of time, still being made relations of these quantities for the number of PZTs, area they occupy, force and pressure applied on them. At the end we can conclude the feasibility of using simple devices in power harvesting systems to generate energy through excitations in pulsed manner and at low frequencies, with higher values in the circuit output in terms of power and current to voltage 5 volts, 108 µW and 21,5 µA (0,53 Kg and 0,83 N/cm2), just like 118,8 µW and 23,6 µA to (2,13 Kg e 3,33 N/cm2), obtained with 8 PZTs, connected in parallel and excited to 1 Hz.

This thesis aims to implement a system called SafeWalk to help visually impaired people to sense obstacles in their path and provide them with more independence and more effortless life routines without any external help. SafeWalk is a low power consuming system designed to replace the daily used white cane. It consists of sensors, a buzzer, a vibrating motor, and a software application. The system will be installed on the user's shoe. It detects the objects in front of the user using an Ultrasonic sensor that measures the distance to the targeted object by transmitting sound waves. This will produce vibration in the shoe and causes the buzzer to start playing when the object gets closer. Similarly, using the provided application, signals will be received in the user's smartphone, which will begin to vibrate when the object is detected. The system works just as planned. The final prototype senses objects in the walking path very well. The connection to the app was strong and never disconnected while in use. The phone vibrates stronger if an object on the ground gets closer; if there is an object in the air, the buzzer and vibrator signal the user.