A versatile data acquisition system for capturing electromagnetic emissions in VHF band

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research investigates the occurrence of EM emissions from compressed rock and assesses their value as precursors to earthquakes. It is understood that electromagnetic emissions are accompanied by crack generation in the Earth's crust, and effort has been targeted on the analysis of electromagnetic signals preceding seismic events. There is a need for a robust Data Acquisition System for the reliable collection of such signals. The design and deployment of a novel system form part of this research. The EM data collected by the Data Acquisition System is subsequently analysed and correlations are made with natural phenomena. The design of the Data Acquisition System is presented and meets a specification which includes accuracy, robustness, power consumption, remote configurability achieved by the development of a novel architecture for flash memories which significantly increases the live span of these devices. The measuring of electromagnetic emissions should be performed by reliable systems, using devices that fully correspond to the specifications set by the needs of this research. This type of systems is not fully covered by existing commercial devices. These prototype VHF field stations (ground base - electromagnetic variation monitors in VHF band) are located around the Hellenic Are. This region is one of the most seismically active regions in western Eurasia due to subduction of the oceanic African lithosphere beneath the Eurasian plate. After approximately two years of electromagnetic VHF data collection, the final stage of this project took place. In this stage, possible correlation between naturally occurring electromagnetic emissions in VHF band and seismic events within a predefined radius around the observation location is investigated. Supplementary, effects of alternative electromagnetic sources, such as solar activity, is considered. Whilst EM emissions from compressed rocks can be demonstrated in the laboratory, it was found from a two-year evaluation that no reliable correlation with earthquake events could be established. However, significant patterns of activity were detected in EM spectrum and it was shown that these correlate strongly with other naturally occurring phenomena such as solar flares. The Data Acquisition System as developed in this thesis has related applications in long term and remote sensing operations including meteorology, environmental analysis and surveillance.Funding was obtained from the National Foundation of Scholarships (I. K. Y.), and co-funded by the European Social Fund and National Resources - (EPEAEK II) ARXIMIDIS

DSP IMPLEMENTATION OF A DIGITAL NON-LINEAR INTERVAL CONTROL ALGORITHM FOR A QUASI-KEYHOLE PLASMA ARC WELDING PROCESS

The Quasi-Keyhole plasma arc welding (PAW) process is a relatively simple concept, which provides a basis for controlling the weld quality of a subject work piece by cycling the arc current between a static base and variable peak level. Since the weld quality is directly related to the degree of penetration and amount of heat that is generated and maintained in the system, the Non-Linear Interval Control Algorithm provides a methodology for maintaining these parameters within acceptable limits by controlling the arc current based upon measured peak current times. The Texas Instruments TMS320VC5416 DSK working in conjunction with Signalwares AED-109 Data Converter provides a hardware solution to implement this control algorithm. This study outlines this configuration process and demonstrates its validity

FRAM based low power systems for low duty cycle applications

Thesis (M.S.) University of Alaska Fairbanks, 2019Ferro-Electric Random Access Memory (FRAM) is a leap forward in non-volatile data storage technology for embedded systems. It allows for persistent storage without any power consumption, fulfilling the same role as flash memory. FRAM, however, provides several major advantages over flash memory, which can be leveraged to substantially reduce sleep current in a device. In applications where most of the time is spent sleeping these reductions can have a large impact on the average current. With careful design sleep currents as low as 72 nA have been demonstrated. A lower current consumption allows for more flexibility in deploying the device; smaller batteries or alternative power sources can be considered, and operating life can be extended. FRAM is not appropriate for every situation and there are some considerations to obtain the maximum benefit from its use. An MSP430FR2311 microcontroller is used to measure the performance of the FRAM and how to structure a program to achieve the lowest power consumption. Clock speed and instruction caching in particular have a large effect on the power consumption and tests are performed to quantify their effect. Two case studies are considered, a feedback control system and a data logger. Both cases involve large amounts of data writes and allow for the effects of the FRAM to be easily observed. Expected battery life is determined for each case when the sample rate is varied, suggesting that average operating current for the two solutions will nearly converge when the sampling period exceeds 1000 s. For sampling periods on the order of one second operating current can be reduced from 15.4 μA to 730 nA by utilizing FRAM in lieu of flash

Comparing the energy requirements of current bluetooth smart solutions (February 2016)

Bluetooth has become a popular way to get access to data delivered by sensors and beacons. To be convenient in use and low cost in maintenance, those sensors and beacons should consume as less energy as possible. Near the energy consideration of the sensing elements, the proper selection of the Bluetooth Low Energy radio and software stack is vital to achieve low power consumption.  There are several solutions on the market, with various claims with regard to power consumption. These claims are not easy to verify on the basis of the data sheets alone, making it long and difficult for engineers to choose the appropriate solutions. We have measured the energy consumption of several Bluetooth Smart solutions that can be found on the market today. The measurements were based on the important communication phases and the information available in various documents (datasheets, application notes). The result of that work is presented here. This work was done at the end of 2015 and early in 2016

Code Generation from JGrafchart to ATMEL AVR

This master thesis has been development at the Department of Automatic Control in Lund University between October 2003 and February 2004 under the supervision of Karl-Erik Årzen.The topic of this master thesis has been to investigate and implement the code generation for an AVR Mega8 microcontroller from JGrafchart, program development by the Department of Automatic Control.This project concerns two items. The first is the code generation for a subset of JGrafchart. The main goal is to obtain a C program that can be compiled for an ATMEL AVR Mega8 processor using the cross-compiler avr-gcc. The obtained program will follow the same execution model as JGrafchart. The second goal was to achieve a bidirectional communication between the host machine, a PC running JGrafchart, and the target machine, the AVR microcontroller. The on-line communication is necessary in order to provide animation of the execution in the target on the host and to provide user interface possibilities from the host to the target. To achieve the animation, a new execution model will be created in JGrafchart. Both, the code generation and the on-line communication have been development in Java language as part of JGrafchart

ARDUINO BASED WIFI ENABLED WIRELESS SPEAKER

This project is to create a system to wirelessly broadcast an audio signal from a computer to a set of speakers using Wi-Fi. This allows one to play music files from a computer and have the sound come out of any speakers that are in range of the wireless network. The ideal use case for this product would involve the ability to have a computer in one room processing music files while multiple speakers throughout the house are actually playing the music. This would be particularly useful in a party setting where one would like to keep a computer safe in a locked room while still being able to use it to play music. Additionally, if a party is there are sets of speakers in multiple rooms, they can all be synced to the same audio source. The major components of the system are the microcontroller receiver module (an ATMega 328p) and the computer program that sends the packetized audio data. This is to create a system that uses Wi-Fi to transmit audio from a source such as a laptop to a speaker system. The final product combines the use of embedded harware, low level software programming, and the IEEE 802.11 standard protocol for wireless communication (Wi-Fi) to create a polished end device. The hardware and software was developed using a combination of original work as open source code and libraries