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Welcome to The Lab Book Pages. A collection of electronics and computing information. You can find out more about this site on the about page.

Recent changes and additions to the site are listed below.

	2 Nov 2014 - Java Web Start Security After an update to Java 7 there are much stricter security measures for starting Web Start Applications. This page describes how to add The Lab Book Pages to a trusted list so that applications from this site will run.
	1 Sep 2013 - Comparator Network Search Tool A comparator with input hysteresis is a useful circuit for cleaning up a noisy signal or a signal with slow slew rates. This page describes a search tool for finding the resistor values for an inverting comparator circuit.
	14 Apr 2013 - Potential Divider Search Tool The Potential Divider Search Tool can be used for finding a pair of resistor values that give the correct voltages in a potential divider circuit. It will also calculate the voltages in a potential divider circuit given the resistor values.
	21 Feb 2013 - Engineering Notation in Java Two simple functions for converting between a double and a string in engineering notation.
	16 Apr 2012 - Simple Nios II HowTo This page provides a quick and simple guide to creating a embedded system based around the Nios II soft processor on Altera FPGAs.
	10 Jan 2011 - BeagleBoard-xM Custom System A complete set of instructions for creating a custom Linux system for the BeagleBoard-xM including, toolchain, boot loader, Kernel and root filing system.
	14 Dec 2010 - Composite Arrays The composite or nested array is a simple approach of improving frequency invariance. It comprises multiple arrays of varying quantity and spacing of elements, each designed to provide a set main lobe beamwidth for successive frequency bands.
	03 Dec 2010 - Delay Sum Beamforming This page introduces the technique of beamforming using an array of microphones as an approach for creating a focused 'beam-like' sensitivity pattern. The simplest form of beamforming, the Delay-Sum beamformer is described.
	03 Dec 2010 - Fractional Delays Steering the mainlobe of a microphone array normally requires delaying the incoming sampled data with sub-sample accuracy. This page describes how this may be achieved.
	29 Sep 2010 - Wave Summation This page is a basic overview of the maths involved in adding sinusoidal signals. This forms a central part of analysing a beamformer's spacial response.
	28 Sep 2010 - Microphone Preamplifier This page includes details of a microphone preamplifier that can be used to build a microphone array. Each amplifier can be used with a small electret condenser capsule and provides a line level output for direct connection to a ADC.
	26 Sep 2010 - Java Configuration File API This is a simple Java Configuration file API. It provides methods for reading key-value pairs from a file. The main benefit over using Java's standard Properties class is support for nested array configuration values.
	23 Sep 2010 - Saffire Pro 10 with Linux This page describes how to use a Focusrite Saffire Pro 10 I/O with Linux. It also provide general information on setting up JACK and FFADO with Gentoo Linux.
	15 Sep 2010 - Java Wav File IO A java class for reading and writing wav files. The class aims to be much easier to use than the approach required by the standard Java API.
	14 Sep 2010 - Beamforming Delay Calculation A fundamental part of beamforming is calculating the differences in wave arrival time between array elements. This page describes how to calculate the time difference between a plane wave front arriving at an array element and an arbitrary reference point.
	26 Jul 2010 - Single Acting Oscillating Steam Engine A single acting oscillating steam engine.
	26 Jul 2010 - Steam Engine Simulator This steam engine simulator allows you to try different engine dimensions for common engine formats, such as single and double acting oscillating engines. It can be run directly from the web page, or downloaded to be run locally.
	8 Jul 2010 - VTK Files in Mayavi Mayavi is a 3D data visualisation tool. It's very handy for making nice plots of various scientific data. This page describes one approach for using Mayavi for displaying data generated outside the Mayavi API. A python script is also provided that watches for changes in the data file and automatically update the visualisation.
	21 Apr 2010 - Gumstix OpenEmbedded Setup After trying to rebuild OpenEmbedded for Gumstix recently, I ran into loads of problems. I've updated this page to include solutions.
	11 Mar 2010 - FIR Filters by Windowing Creating FIR filters using the windowing technique is simple and quick to do. This page describes the process for creating low pass, high pass, band pass and band stop FIR filters.
	11 Mar 2010 - Creating PNGs using libPNG The libPNG library can be used for creating PNG image files. This page describes the process of creating a PNG file from an array of floating point values. Very handy for saving graphs.
	04 Feb 2010 - Waveform Generation Functions A collection of c functions for generating wav files of various waveforms such as simple tones, frequency sweeps and white noise.
	29 Jan 2010 - Working with Wav Files Routines for handling wav files, such as reading and writing in c and GNU Octave.
	21 Jan 2010 - FPGA Configuration Some tips on FPGA configuration, including Impact batch mode and USB FPGA configuration under Linux.
	11 Sep 2009 - VHDL I²C Controller Modules This is a very handy module if you are dealing with I²C and FPGAs. It gives you a programmable I²C master that allows you easily interface to multiple I²C devices.
	11 Sep 2009 - Site Statistics Page A collection of site access statistics. The data is gathered using Google Analytics, exported using the Google Analytics Data Export API, parsed with PHP and plotted using Google's Chart API.
	01 Sep 2009 - Digital Switch Debouncing The section on digital debouncing has been updated. It now contains a full description and VHDL module for debouncing switch signals using a digital circuit.
	22 Aug 2009 - Otsu's Threshold Method Otsu's method is an algorithm for reducing a greyscale image into a binary image. This page describes the theory and provides a Java implementation.
	17 Aug 2009 - Robot Wheel Encoder The wheel encoder page has now been updated with a sample VHDL module and testbench.
	11 Aug 2009 - Blob Detection Algorithm The algorithm described on this page can be used for finding blobs (regions of connected pixels) within monochrome images. A demo program using the algorithm is supplied. The code is in Java, but can easily be ported to other languages.
	15 May 2009 - Java: Direct Image Buffer Access This page section describes how to create a buffered image with access to the underlying image data, very handy if you are doing image processing tasks.
	07 May 2009 - Quick PicoBlaze Program ROM Update The PicoBlaze is a very handy simple 8bit microprocessor. This page describes how to update the program ROM without having to resynthesise, place and route your design after every code change. A real time saver!
	23 Apr 2009 - Linux Running on XUP-V2Pro FPGA Board This page describes how to get Linux running on a XUP-V2Pro Xilinx FPGA board. It is based in the PetaLinux distribution and runs on the MicroBlaze softcore.
	22 Feb 2009 - Pipelined Processor Simulator This Java based simulator will help those wishing to learn about pipelined processors get a deeper understanding about how they work. It is completely programmable and comes with a simple Conway's Game of Life demo.
	21 Feb 2009 - Robot Wheel Encoder Detecting wheel motion is a common task in robotics. This page includes information on setting up a simple system for detecting the amount and direction of wheel rotation.
	15 Feb 2009 - Real time Dynamic Web Pages This page describes some techniques for creating web pages that update their content to reflect changes in dynamic data.
	02 Nov 2008 - Atmel AVR Toolchain A set of instructions on setting up a AVR development toolchain, including how to use a Xilinx DLC5 (Parallel Cable III) cable to program an AVR using its JTAG interface.
	15 Jun 2007 - Tektronix Scopes The start of a few notes on Tektronix Scopes. So far, it only contains information on using the screen capture function.
	14 Jun 2007 - LCD Module Driver A simple VHDL LCD module driver.
	29 Mar 2007 - Parallel Port Info Some information on making use of a PC parallel port for general IO.
	01 Jan 2007 - XUPV2Pro Info A crib sheet for details on the XUP-V2Pro FPGA development board.
	31 Oct 2006 - HTML Symbol/Character Reference A set of tables containing codes for symbols and characters for use in web pages.
	12 Jul 2006 - PDF Joining How to combine multiple PDFs into a single PDF file; handy for printing and storing books that are only available in separate sections.
	13 Apr 2006 - HW RNG A project I'm working on needs a digital hardware random number generator. This page describes the RNG used and how it fares at producing random numbers.
	28 Feb 2006 - Java Primitives Added a new page for Java related items. At the moment it only contains information on java primitives.
	27 Jan 2006 - VCC VW-300 Page The VCC VW-300 is a FPGA development boards, this new page contains some useful info and links to data sheets.
	04 Jul 2005 - Bash Tips A few sections of code that could be useful when writing bash scripts
	04 Jul 2005 - SSI Info Some info about SSI that I always forget.
	19 Jun 2005 - Links Set up the links page.