Navman GPS receivers, and the like, are great, until you actually want to use their received GPS data on a computer in real-time. Luckily there are plenty of resources to do this (NavmanUnlocked, the forum, MioPocket, GPSPasSion and GPSUnderground). In addition, I recommend SiRFTech for GPS testing. There are many tools available too, such as SSnap, which is extremely useful to track registry and filesystem changes. This is especially good when creating a one-off .reg file that you can import after a hard reset to restore the state of WinCE (in particular Bluetooth pairings).

Here, I give a quick guide to turning a Navman S150 into a Bluetooth GPS receiver that one can use with gpsd on a Bluetooth-enabled computer.

Behold the trusty S150 running WinCE Core 5 and PNADesktop (which is launched from \Program Files\Navman\appstartupsec.ini - the other apps, e.g. SmartST, are manually disabled):

I was suprised to find that seemingly none of the dedicated GPS iPhone apps could stream your current location to a computer. Therefore I knocked up this simple solution, which uses a Python script to wrap up gpsd and make it think it's connected to a real GPS receiver that outputs NMEA sentences. The receiver is of course the iPhone, which uses Javascript (to retrieve location) and basic AJAX (to send the results to the Python script) all running in Safari. The page is served from Python via WiFi or a tethered connection (Bluetooth or cable):

I was disappointed to find that the improved Linux Kernel Orinoco drivers do not report power levels via the standardised iwconfig 'monitor mode'. When the iwpriv 'monitor' mode was available, Prism II packets were sent from the driver to userland. These packets contained extra information reported by the hardware, such as per-packet signal & noise levels. I think having SNR measurements is one of the most useful features of Kismet, as it allows to you roughly determine the direction to a network based on signal power. Therefore I took the old-style monitor mode code and transplanted it into the modern driver (in kernel version 2.6.23.9). Now both monitor modes are accessible. Kismet picks the older one (Prism II packets) first, before trying the standardised mode.

TokyoCabinet (TC) is a wonderful open-source key-value pair database library by Mikio Hirabayashi, part of his TokyoProducts suite. TokyoTyrant (TT) is the networked portion of it (i.e. the database client & server). Since I am working on a project in Visual Studio under Windows and set out to use TC over the network, I needed to access the TT client API with MSVC.

I a gave presentation at Dorkbot Sydney (24/02/2009) on the Eyesweb Visual Programming Language. It was an overview that exemplified some cool things you could do using live video, iPhones (with accelerometers), mrmr, OSC, and multiple Eyesweb nodes on a network.

I wrote the following major system components:

1) A multi-threaded, load balancing MPEG-2 video decoder engine, featuring:
• Automatic memory management & caching
• Level-Of-Detail support and seamless transitions
• Continuous playback or shot looping (given cut information)
• Asynchronous loading and destruction

[Initial tests indicate it can play over 500 videos simultaneously on one computer (with 2 HT CPUs and 1GB of RAM at the lowest LOD). TVisionarium is capable of displaying a couple of hundred videos without any significant degradation in performance, but there's so much still to optimise that I would be surprised if it couldn't handle in excess of 1000.]

With my latest optimisations, TVisionarium is able to play back 1000 shots simultaneously!
While profiling the system, total CPU usage averages around 90-95% on a quad-core render node!
This indicates that those optimisations have drastically minimised lock contention and support far more fluid rendering.
Have a look at TVis in the following video:

This is an in-development 'video tube' test of the video engine:
(Watch it on youtube.com to leave comments/rate it if you like.)

T_Visionarium was officially launched on 08/01/2006 as part of the 2008 Sydney Festival. Please read my blog post about it. Here are some pictures:

The festival banner:

Crowd before the speeches:

The digital maestros (Matt McGinity & I):

09/01/2007 - SBS World News:

August 2006 - Channel Nine News:

This series of pages summarises the contribution I made to TVisionarium Mk II, an immersive eye-popping stereo 3D interactive 360-degree experience where a user can search through a vast database of television shows and rearrange their shots in the virtual space that surrounds them to explore intuitively their semantic similarities and differences.

It is a research project undertaken by iCinema, The iCinema Centre for Interactive Cinema Research at the University of New South Wales (my former uni) directed by Professor Jeffrey Shaw and Dr Dennis Del Favero. More information about the project itself, Mk I and the infrastructure used, is available online.

I was contracted by iCinema to develop several core system components during an intense one month period before the launch in September of 2006. My responsibilities included writing the distributed MPEG-2 video streaming engine that enables efficient clustered playback of the shots, a distributed communications library, the spatial layout algorithm that positions the shots on the 360-degree screen and various other video processing utilities. The most complex component was the video engine, which I engineered from scratch to meet very demanding requirements (more details are available on the next page).

Luckily I had the pleasure of working alongside some wonderfully talented people: in particular Matt McGinity (3D graphics/VR guru), as well as Jared Berghold, Ardrian Hardjono and Tim Kreger.

(unfortunately this will not help if you lose an entire disk*)

The vast majority of the information presented here I inferred from my own recovery experience – it may be inaccurate or utterly wrong, so use it at your own risk. I do not take any responsibility whatsoever for your data after you apply any of the knowledge described in this document.

RAID 0 (AKA ‘striping’) creates one logical disk out of multiple, identical physical disks. The total capacity is the sum of the individual disks. It offers higher data throughput, but does not actually provide any data redundancy whatsoever. Each disk is proportioned into many identically-sized ‘stripes’, which form a continuous chain when seen from the point of view of the whole logical disk. The stripes are shared in such a way that the first physical disk contains the first stripe, the second physical disk the second, and so on, until we return to the first physical disk where the count continues. The RAID controller stores metadata in track 0 of the physical disk(s) that dictates the configuration of the RAID array. If this metadata is corrupted or lost, the logical RAID 0 disk will be lost, the controller will treat the physical drives as individual, separate logical drives and the data will be inaccessible because it is split over multiple discs. This guide attempts to show how one can recover the logical RAID 0 disk when little information is know about physical & logical disk parameters, and partition & file system information a priori.

I fixed the lighting calculations and thought I would use a built-in texture:

Here is a fly-through of the standard tornado simulation with some pretty filaments:

Shortly after the presentation day, I ripped out the original physics code that someone (who shall not be mentioned!) had written in the minutes prior to the presentation and replaced it with more 'physically correct' code:

A little something I made in my spare time:
(More details coming later...)

This started with my desire to build a Woktenna.
Of course you can't very well put a PCMCIA wireless card at the focal point of a cooking wok!

So the alternative is using a USB WiFi adapter that can hang on the end of a USB extension cable and
introduce minimal analog signal loss and USB is digital!

Despite the fact is says "Linux compatible" on the box, it wasn't immediately possible to do what I wanted to do,
which is: monitor mode!
With monitor mode, I'd be able to point the woktenna around and pick up the beacon frames of distant APs.

I found two drivers available for this device:
one over at BerliOS,
and the other at SourceForge.

I have made the following WiFi antennas:

Cantenna

Made two, same design for both.
Gain is good: ~12dB.

Thanks to the generosity of Aras Vaichas, I came into possesion of an old (1992) 60x8 dual-colour LED display. As it was just the display itself (no manual, instructions, software, etc) I set about reverse engineering the board. Using my multimeter I re-created the schematic for the board and found all the relevant datasheets online. Having figured out how to talk to the display, I interfaced it via the parallel port and wrote some control software for it. Once I could display various test patterns (multi-colours sine waves), I 'net-enabled' the software so that the display could be controlled over a network via UDP packets - the resolution is so low that the entire LED configuration fits into a single packet! Finally, I wrote a plugin for Winamp that streams the frequency analysis of the playing song to the display, which produces results like this:

My major project for PHYS2601 'Computer Applications 2' in 2003. You can read the actual report (PDF) or report (broken Word-exported HTML), which details the design, electronics, firmware and testing.

When I first started developing on Linux and using Makefiles, I started with simple Makefile scripts and later built upon each preceding one. What eventuated is the attached set of files that should make compilation of multiple sources into a single target an easier exercise. There are, of course, many other alternatives, such as Automake, Bakefiles and CMake (all of which are far more sophisticated).

This is a GUI frontend to the genetic programming assignment given in this subject. The aim is to evolve a wall-following robot. The program provides multiple visualisations of the process. It was written with Janice Leung - many thanks for the beautiful widgets! Developed on (but not for) Linux using Python and its bindings & add-ons: PyQt, PyOpenGL, PIL and psyco. README available. It contains more information about the code used to render the robot & world.

Ever wanted to know what a particular error code means when you are left without the informative error message text?

My friend Rafal Kolanski and I decided one night to put our gigabit network cards to the test and measure how quickly a user-space program could generate packets and how many would be discarded before the destination's NIC would receive them. Therefore we wrote a small Linux program to complement my Broadcast Flooder, which I had previously written to test other aspects of my network.

If you need to establish a PPP connection from a device to your Linux box, then do the following:

1. Make sure your Linux installation is set up to support Bluetooth connectivity

• Bluetooth is enabled and compiled into the kernel
• The kernel drivers for your Bluetooth dongle are also compiled and installed
• Bluetooth user-space applications are installed (specifically here we need dund - the BlueZ Bluetooth dial-up networking daemon)

Although there exists a plethora of programs that count lines of code, I thought I would write my own. It is designed to analyse C/C++ code and ignore whitespace, // and /**/ comments (both the single and multi-line sort). It also counts the number of FIXME's one has left in their code. Other languages (eg: Javascript, assembly) that also use such commenting conventions are compatible too.

• Xnest

If you are in an existing X Windows session and would like to open a session on a remote computer that is also running the X server, you can simply use Xnest in the following way:

Xnest :1 -query (remote host)

Using my modified version of ffdshow, which sends a video's motion vectors via UDP to an external application, I visualised the motion vectors from The Matrix: Reloaded inside my fluid simulation. The grid resolution is set based upon the macro-block resolution in the video sequence and each type-16x16 motion vector controls one spatially-matching point on the velocity grid. The following visualisation is taken from the scene where they are discussing the threat to Zion while inside the Matrix before Neo senses that agents are coming (followed by Smith) and tells the ships' crews to retreat.

This is the new-and-improved fluid simulation in action. I'm perturbing the 'blue milk' with my mouse. Watch for the darker region form and expand behind the point of perturbation. Due to finer resolution of the velocity grid, the linear artifacts apparent in the earlier version have disappeared and it now looks smooth in all directions.

Velocity-grid-based 2D fluid simulation with effects that interestingly enough resemble Navier-Stokes simulations.

To more carefully study the effects of reversing motion vector directions, I created a 'control' video of me making particular motions at different speeds. You can witness the results: