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February 16, 2008

Vector MAME

There's a special place reserved in my digital heart for the classic arcades like Tempest and Asteroids, and ironically it's because of the flawless analog goodness of their vector-based displays. I still boot up a Tempest emulator for the Dreamcast from time to time, though while it remains fun to play, it just has no soul on a standard CRT.

There was a post on MAKE a couple months ago about a guy named James Brown who hacked a driver for MAME that displays on an oscilloscope via a soundcard's analog output. Unfortunately, aside from photos, videos and a Gizmodo interview, I don't believe drivers or a howto ever turned up for this.

I spoke with the Google about this subject today, and I came across the VectorMAME and the Zector Vector Generator (ZVG):

There were more than 30 vector based games made in the 80's. To acquire a collection that includes all these games would be a monumental feat. Just to find that many vector monitors alone would be no easy task, not to mention the cost! Vector based arcade monitors haven't been made in 20+ years, and you can't simply use one vector monitor for all these games. Each monitor has different specs and runs at different speeds, making them incompatible between different gaming hardware. The hardware was unique for most of these games, making Multigame conversion kits difficult to design. And good luck finding an Aztarac, Sundance, 4-Player Eliminator, or one of our namesake, a Zektor cabinet! Some games are rare enough that even lots of money can't get you one!
After collecting vector games for years, the realization that you can never have them all sank in, and we looked for an alternative. Why not build a Vector Generator that would somehow attach to a standard PC and run all the games supported by an emulator, such as MAME, on a single vector monitor? It would be kind of a 30+ Vector Multigame!

The ZVG connects to your PC via parallel port, and Zector claims it is able to drive most old analog vector monitors that you are able to obtain. It's even able to drive an oscilloscope in X/Y mode. VectorMAME provides the ZVG drivers for DosMAME, which would allow you to put together a MAME cabinet that will play all of the old vector games on a real X/Y monitor. The hardware will set you back a couple hundred bucks, but it appears that this might be the only way to play some of your old favorites in all their glory.

Does anyone know if soundcard-oscilloscope drivers ever became available? It's not as fun as a full 19-inch monitor, but I'm surprised that this hack hasn't been released or recreated at this point.

Zector Vector Generator and VectorMAME - Link
MAME on an Oscilloscope: James Brown Interview - Link

February 15, 2008

Hack request: electronic cat door

An anonymous reader requested a hack today to solve a particular kind of kitty problem. Specifically, the reader wants to know if there's a way to have a cat door that grants access to particular cats while restricting entry or exit for others. Not being a cat owner, I don't follow cat electronics too closely, but I have heard of a project or two that are similar in nature, and I'd like to open this up for further discussion in the comments.

The photo above is from the Flo Control project. This cat, Flo, had a nasty habit of bringing in dead mice to the house. Her owner created a computer controlled system that captures an image of the cat as it approaches the door. The PC does some image recognition to determine if the cat's silhouette is atypical (ie. carrying something nasty) and only unlocks the door if the cat is sans-mouse.

One element that's used in the Flo Control setup is a cat door product made by Cat Mate. They make a few different models of cat doors that require your cat to wear a special collar to be allowed through. These are typically operated by a magnet or infra-red beacon in the collar which is able to mechanically or electronically unlock the door. My guess is that something like this will probably will do the job, but if your neighbors start doing the same thing, there's nothing to keep other cats with a collar from getting in.

A more interesting idea is to use RFID to uniquely identify a particular cat and grant access accordingly. There's a commercial product called Pet Porte that is able to do this with the RFID chip implants that some owners are sticking on their animals these days, but I figure it might be more fun to make your own, perhaps using a tag on a collar.

There are a number of RFID sensors for the Arduino and Basic Stamp microcontrollers. It'd be straightforward to program one of these to accept specific RFID tags and then trip the lock switch in a slightly hacked Cat Mate door. The only problem I see is devising a collar that wouldn't bug the cat and would also place the RFID tag in close enough proximity to the reader. Any readers out there with thoughts on this?

The Flo Control Project - Link
RFID Enabling Your Front Door - Link
Using the Arduino with the Parallax RFID reader - Link

February 14, 2008

Nifty Corners: roundtangles made simple

Since the border-radius CSS parameter has been too slow in coming and rounded corners don't seem to be going out of style any time soon, everyone web developer I know has their own personal brand of CSS background-image and DIV gymnastics for creating smooth-cornered roundtangles. Besides the extra load time that's required to download all those corner images, it's just a lot of extra work. The general principle of unnecessary work is against my slacker sensibilities, which is why the Nifty Corners Cube javascript library caught my attention.

Nifty Corners uses Javascript to dynamically add rounded corners to HTML elements at runtime, without the use of images. You can choose a corner style and tell Nifty Corners what CSS id, class or element to apply it to. The javascript function will dynamically alter the specified elements, drawing 1px high DIV strips at the top and bottom of the element to give it the rounded corners. The effect can be used for everything from rounded content areas to tab-menus.

It won't solve every problem—rounded borders, in particular, are still a bit of a nuisance—but it'll make your work a lot easier for many design challenges and it's compatible with Firefox, Safari and IE 5.5-7.0.

Nifty Corners Cube - Link

February 13, 2008

Apartment-friendly bike rack

It's hard to find a good place to store your bikes when you're an apartment dweller. Here's a nice looking bike rack made from a few cheap Ikea shelving parts.

All you need to get from ikea is one stolmen post, two brackets and four hooks. you'll also need some screws and some aluminium 20x20mm square pipe, maybe some foam rubber.

I think I'll give this a try in my garage to clear up some needed floor space.

Stolmen Bike Rack - Link

What's your poison?

Robert Bruce Thompson, author of books on everything from PC Hardware to Astronomy, is working on a new book for Make: the Illustrated Guide to Home Chemistry Experiments. So, we've got chemistry on our mind here, which led Dale Dougherty, the Publisher of Make, to ask Robert:

I read a story last week about the alarmingly high levels of mercury found in fish in the top sushi places in Manhattan. Ever since, I've been wondering is it possible/feasible/reasonable to test for mercury in fish -- a DIY mercury test kit. I doubt you could do this in restaurant so let's presume that this is a test kit for store-bought fish.

The answer for mercury is a bit complex:

The problems are that mercury is toxic at unbelievably low levels and that it is a cumulative poison, which is to say it isn't excreted. Accordingly, the allowable levels are set so low that there's no chance they could be detected by any wet chemistry test with a sample of any reasonable size.

I was pretty sure of my facts, but just to be certain I ran them past organic chemist Dr. Paul Jones. His response was, "Maybe you could use a wet chemistry test if you had an entire 500-pound tuna for your sample, but otherwise you'd have to use instrumental tests."

Organic chemist Dr. Mary Chervenak points out the Reinsch Test for mercury (which also produces a positive for several other heavy metals). You dissolve the sample in dilute HCl and put a copper strip in the solution. Any mercury present plates out on the copper as a silvery mirror. The trouble is, if enough mercury is present to produce a visible mirror with the Reinsch test, that sample has enough mercury in it to poison everyone in a radius of several blocks.

Robert's got more details over at his daynotes journal, and a couple of other tests have come to our attention since Dale's original question. Dale sent a link to a Heavy Metals Test (Robert posted his thoughts on this test in his journal as well), and Popular Science just posted a link to a portable blood test for heavy metals. Have any of you come across some interesting tests for poisons in your body, food, or environment? What results have you had?

From The Maker Store:

Illustrated Guide to Home Chemistry Experiments by Robert Bruce Thompson
Price: $34.99
Pre-order/Buy: Maker store - Link.
For students, DIY hobbyists, and science buffs, who can no longer get real chemistry sets, this one-of-a-kind guide explains how to set up and use a home chemistry lab, with step-by-step instructions for conducting experiments in basic chemistry. Learn how to smelt copper, purify alcohol, synthesize rayon, test for drugs and poisons, and much more. The book includes lessons on how to equip your home chemistry lab, master laboratory skills, and work safely in your lab, along with 17 hands-on chapters that include multiple laboratory sessions.

February 12, 2008

Haiku running in QEMU

The death of BeOS was an incredible shame. I sometimes wonder what modern operating systems, developer interfaces, and hardware hacking tools (remember the geek port?) would be commonplace today if this weird tangent in computing history had really taken off. An Ars Technica article about the open source BeOS "Haiku" project caught my eye today, and I was pleasantly surprised to discover that BeOS development is still alive and kicking.

I've only been playing with it for a few minutes, but it's up and running nicely in the Q virtual machine (QEMU port for OS X). There are nightly disk image builds available for download, and QEMU will boot directly from any of the RAW image downloads. So far everything seems to work reliably.

One thing that isn't completely functional, however, is the drive setup utility. This is a drag, since there's only a few free MB available on the downloaded disk image. Unless you go through the trouble of preparing a BeOS boot volume from within a separate Linux virtual machine, you won't be able to install much of anything. Can any Be hackers comment on a command line method for formatting and preparing a boot image?

Haiku poetically resurrects BeOS - Link
Haiku Operating System - Link

February 11, 2008

Wii Twilight Hack

A demo of the first Wii ELF loader is now available for download, thanks to bushing, Segher, and tmbinc. It takes advantage of the Twilight Princess savegame overflow from a couple of weeks ago, but now there's something more substantial for people to try out on their own hardware.

Had my Wii not been stolen, I'd report back with more info, but from what I understand, this isn't working correctly with at least one US Zelda revision.

You can track the latest Wii homebrew progress at the WiiBrew Wiki. From the looks of the video, these guys are probably very close to a bootstrap file that will load in an arbitrary homebrew application.

Wii Twilight Hack - Link
WiiBrew Wiki - Link
Wii Linux Wiki - Link

February 10, 2008

Extracting GTA3 art assets for use in your own game

One of the most frustrating things about homebrew game development is that there's almost an insurmountable amount of work that needs to be done just to get something decent to display on a screen. You can roll your own complete graphics and physics engines and still have nothing to show for it if there are no art assets to load.

QuantumG's solution to the problem was to focus on developing the game engine using the model data from GTA3. Knowing that the art is already functional in another game allows you to focus on your code, and it's more fun when you can see the immediate results of your work.

The blog entry walks you through his experience with extracting and using the mesh, texture, city, and character data and making use of it with the OGRE graphics engine. If you've ever played around with making a game before, but got discouraged for lack of art assets, this is really worth a read.

Using GTA3 art assets in OGRE - Link
OGRE 3D graphics engine - Link

February 9, 2008

Add an "Open with Notepad" option to the right-click menu

The How-To Geek posted this easy Windows registry hack that will add an "Open with Notepad" option to the right click menu for all files:

Open regedit.exe through the start menu search or run box, and then browse down to the following key:
HKEY_CLASSES_ROOT\*\shell

Right-click on "shell" and choose to create a new key, calling it "Open with Notepad". Create a new key below that one called "command". Double-click on the (Default) value in the right-hand pane and enter in the following:

notepad.exe %1

The other option is to drag a shortcut to the Notepad application to the "Documents and Settings\Username\SendTo" folder. I dig how the registry hack adds it right to the top of the context menu, though. More often than not, I want to open a file with Notepad, regardless of its default file association, so it saves some time having this at the top of the list.

Add "Open with Notepad" to the Context Menu - Link

February 8, 2008

HOWTO: cross-browser alpha PNGs

If you're a web designer, here's a tool that's going to make your life a lot better. Seriously, in no time you'll be dropping shadows like Galileo dropped the orange.

Transparent GIFs only have a single bit of transparency—a pixel is either totally transparent, or it's completely opaque. 24 bit PNG images, on the other hand, have a bona fide alpha channel, allowing your images to have a full range of transparency. Problem is, they have poor browser support in IE.

The indexed PNG 8 format is similar to the GIF format, and I had always thought that it only allowed boolean transparency. It turns out the PNG 8 format is a little more clever. You still have a 256 color index palette like the GIF format, but the format allows for each index to have its own transparency level, and that level can be set at any amount of opacity!

Here's the real kicker. Even old versions of IE support the PNG 8 format to some degree. So on Firefox, Safari, and IE 7 you can have full alpha support without using any of the quirky IE specific PNG hacks. Older versions of IE will still display your alpha PNGs, but they will revert to a GIF-like all or nothing transparency. Any portion of the image which is semi-transparent will be forced to fully transparent.

To sum it up, the PNG8 alpha format gives you complete cross browser alpha transparency for all modern browsers, and it degrades gracefully for older versions of IE that some people may still be using. As an example, the image above is a semi-transparent PNG8. Most of you will see the blue gradient fade around the edge of the light bulb. Those of you with older versions of IE will see a hard edge around the bulb, similar to what you'd get with a GIF.

Correction: my example is a little goofed, as the blue in the image obtained a partial transparency during the quantization process. IE users will only see some of the bottom portion of the bulb, specifically colors that didn't match the transparent portion in the RGB space. For normal drop-shadow overlays, this does not usually pose a problem. Remember, though, that converting to PNG8 means bringing thousands of color and alpha values down to 256. If your solid colors get mapped to a partially transparent index, they will disappear in older versions of IE.

A coworker introduced me to this today and showed me how Fireworks has an export option for PNG 8 that enables this full-alpha mode. I hadn't been aware of it, because Photoshop has no such feature, only allowing GIF-like transparency for 8 bit PNGs. Unfortunately, I really ~~hate hate~~ have a hard time with Fireworks, and I don't want to purchase it.

A little searching, though, and I found pngnq, a command line tool that will quantize a PNG24 image into a 256 color PNG8 image with alpha transparency. Here's how you use it:

Export ("save for web" in Photoshop) your image in the RGBA PNG-24 format
At the command line, run "pngnq filename.png"
The image will be converted and the output named filename-nq8.png

To install pngnq, just grab the binary from the link below and copy the pngnq executable to somewhere in your path. In OS X, you can put it in /usr/local/bin and add that to your PATH variable (or just toss it it /usr/bin). The program requires the libpng library in order to run. This isn't pre-installed on a Mac for some reason, so you'll have to build it from source, use Fink, or use the installer at the site conveniently listed below.

pngnq - Link
libpng installer for OS X - Link

February 7, 2008

FART: easy grep-like utility for Windows

The Find And Replace Text utility is a handy little command-line tool to have if you're a Windows user. It can function as a simple grep-like utility for quickly searching through whole directories of files, and you can also use it to perform mass search and replace operations on a file or group of files.

The command format is fart <options> filename search <replace>. Basic options are -r (recursive), -c (print filename and match count), -i (ignore case), -n (print matched line numbers), --c-style (interpret backslashes as c-style characters).

For example, let's say a Linux buddy of yours sent you a bunch of html files and they have unix line endings that are barfing in notepad. One simple command fixes the problem, replacing all the newlines with a full PC carriage return, line feed combo:

fart --c-style *.html \n \r\n

Or perhaps you need to quickly track down some work that is left to be done throughout a big project directory. You can use fart to recursively search a directory and spit out all the file names and line numbers containing the text "TODO":

fart -nr * TODO

It's easy to see how you could shoot yourself in the foot with this one. Make sure to fart with caution and back up your files before doing a big search and replace.

FART @ SourceForge - Link

February 6, 2008

TrueCrypt for OS X

TrueCrypt 5.0 was released yesterday and OS X has been added to the list of supported operating systems, making it the only open source volume encryption utility that works in Linux, Mac and Windows. It's a really slick utility for creating an AES-256 or Serpent encrypted volume that you can drop sensitive files inside.

You can use TrueCrypt to create an encrypted volume image inside a file, or you can encrypt a whole disk image or partition. The OS X version uses MacFUSE to provide user-mode mounting of the encrypted disk. The main application window, pictured above, gives you a simple interface for creating and mounting encrypted images.

Once an image is mounted, you can use it like a normal hard disk. Unmount the disk and you're left with a file full of random gibberish. FAT is the only filesystem that's available through the interface, but once the disk is mounted, you can reformat it with Disk Utility to use XFS.

There are a couple of things worth noting. In the Windows and Linux versions a special bootloader is available that lets you encrypt your entire system drive. It doesn't look like that option is available in the OS X version. Also, when I tested the latest OS X binary this evening, the "hidden volume" plausible deniability feature wasn't working. Hopefully that will be added in a future release. Until then, TrueCrypt is better suited for storing tax documents and things you wouldn't want visible to a laptop thief, rather than the details of where you've hidden the bodies.

TrueCrypt - [via] Link

February 5, 2008

Wii Drum Kit

The Wii Drum Kit is another great example of a tangible user interface made possible with the Wiimote. The latest version adds support for the Nunchuck, so you can use both hands to play your virtual drum kit. This one is a Windows application, and source is available at the This is Not a Label blog.

The Wiimote + Nunchuck combination seems like the perfect interface for an air drum. Different gestures are used to trigger a specific drum, so the high hat is a flick to the side, the snare is a forward hit, etc. There's no kick pedal, of course, but the fist stamping motion that's used is a reasonable alternative.

Wii Drum Kit - Link
Control Your Applications With a Wiimote - Link

February 4, 2008

Ubuntu Tweak

Hans sent us a link to HowtoForge's guide to installing and using the Ubuntu Tweak utility.

Ubuntu Tweak is a tool that lets you change hidden Ubuntu settings, for example: hide or change the splash screen, show or hide the Computer, Home, Trash, and Network icons, change Metacity, Nautilus, power management, and security settings, etc.

It's only applicable for the Gnome desktop, but it's a really convenient tool for tweaking your computer's splash screen, desktop and hibernation settings. There's nothing here that you can't do via other settings management programs or config files, but the interface is simple to use and it collects a lot of Gnome's system settings in a single application.

Tweaking Hidden Ubuntu Settings With Ubuntu Tweak - [via] Link

February 3, 2008

Rebuild a Roomba battery

Before you buy a replacement battery for your dead Roomba, you might want to consider rebuilding the pack yourself. You can get a couple of 6 cell Sub-C NIMH packs for less money and more amp hours than the stock battery.

I've been wondering whether it would be economical to just rebuild the battery pack, versus buying a new one. From the looks of it, all it takes is 12 NiMH cells, and from the looks of the case, it looks to be C-Size form factor. For less than $36, I can pick up 12 4500 mAh C cells. I can see iRobot has tried to prevent people from doing this by using TRIANGLE bits for their battery cases, but that's simple to get through.

To remove the triangle bits, just find a small flathead screwdriver that you can wedge in nicely.

Rebuilding a Roomba Battery for Less - Link, Photos

Experiment with a virtual neuron

The Neuron

Over at the Mind Hacks blog, Vaughan writes:

The Children's Hospital Boston have created a fantastic 'virtual neuron' which allows you to explore the basics of neural transmission with an interactive flash demo. Strictly speaking, of course, it's designed for children, but it's remarkably good fun whatever your age. Once you've got the demo window up, the options at the top of the screen allow you to choose different demonstrations, and the text below explains what's happening. Yay!

Virtual neuron at Children's Hospital Boston

Mind Hacks Cover
Mind Hacks by Tom Stafford and Matt Webb
Price: $24.95
Buy: Maker store - Mind Hacks
This exploration into the moment-by-moment works of the brain uses cognitive neuroscience to present experiments, tricks, and tips related to vision, motor skills, attention, cognition, and subliminal perception. Each hack examines specific operations of the brain. By seeing how the brain responds, you'll learn more about how the brain is put together. If you want to find out what's going on in your head, then Mind Hacks is the key.

February 2, 2008

Sidebar separator hack for OS X

Becky Stern forwarded us Jonathan Berger's simple and useful hack that adds dividers to the Finder sidebar.

I use the Finder's Sidebar pretty heavily, but it was getting to be a mess that could really use some dividers. Solution? Make an empty folder called " ..................." and stick it in there.

You'll need a leading space with periods. Dashes also work and patterns like " - - - - - -" are satisfying too. Periods work particularly well, because you can make the filename long and when it's abbreviated in a skinny sidebar it'll still look correct with "..." added at the end.

To add more than one separator, you need a unique folder for each one. To do this, you can either make folders with different numbers of periods, or, for a consistent length, just place all the folder copies inside each other like Russian dolls.

The final trick is to give the separator folders a blank icon to disguise the fact that they are just folders sitting in your sidebar. I was too lazy to do this part and I'm still happy with the effect, though it doesn't look quite as hot as Jonathan's screen grab above.

Hacking Separators Into the Leopard Finder Sidebar - Link

February 1, 2008

Meta-model: tools for clarifying communication

Hackszine reader nathaN writes:

i have mind performance hacks here on my lap, and i found hack 56. you included transformational grammar, surface/deep structure, you have to be aware of this other book on my desk, next to my lap. The book describes a method of using transformational grammar to analyze statements and gather incredible amounts of information, the technique is called the Meta Model, i had to write this post after i found #56 in your book. it's out of print, i think, but it's not too hard to find used if you make a few calls. it cost ME $35, but its probably online as well, torrents or whatever =(
its the single most useful "hack" i've ever found, ive been using it for about an year and it gives me more options than i know how to take advantage of.

The Structure of Magic I, by Richard Bandler and John Grinder
Introduction by Virginia Satir and Gregory Bateson.
Science and Behavior Books, Inc
copyright 1975

Unfortunately, the Google Books entry for The Structure of Magic I wasn't a full scanned version. There is, however, a wealth of information about the Meta-model and other Neuro Linguistic Programming (NLP) tools on Wikipedia:

The meta-model in neuro-linguistic programming (or meta-model of therapy) is a heuristic set of questions designed to specify information, challenge and expand the limits to a person's model of the world. It responds to the distortions, generalizations, and deletions in the speaker's language.

In the process of communicating, the mind is forced to translate a person's experiences and their internal understanding of the world into words, making language a highly optimized and compressed representation of a complex internal mental state. This translation occurs a second time, as the listener parses language and interprets that communication based on their own mental world model and past experiences.

The meta-model provides tools for quickly parsing the structure of a communication, determining implied meaning, and locating potential points of misunderstanding. When you can recognize the linguistic translation artifacts that are common patterns in the communication process, you can respond to them. On the receiving end, this helps you better understand the experiences that underlie the speaker's language. On the sending end, it helps you to better communicate without misunderstanding. Internally, it helps you to analyze and debug your own model of the world.

Meta-model (Neuro-linguistic Programming) - Link
Mind Performance Hacks @ the Maker Store - Link

January 31, 2008

R: open source statistical computing

I was digging around for an open source statistics package today and came across R, a GPLed statistics and and data analysis suite. Sweet!

R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, ...) and graphical techniques, and is highly extensible. The S language is often the vehicle of choice for research in statistical methodology, and R provides an Open Source route to participation in that activity.
One of R's strengths is the ease with which well-designed publication-quality plots can be produced, including mathematical symbols and formulae where needed. Great care has been taken over the defaults for the minor design choices in graphics, but the user retains full control.

So I've been messing around with this for the last half hour and it's really an exciting package, especially if you're a coder or unix geek. You interface with R through a command line programming interface, executing simple statements, setting variables, and defining functions. It feels similar to issuing commands at a unix prompt, except you're working with data sets instead of file descriptors.

What's cool is the robust capability of the standard function set. Want to read in a data set from a tab delimited table you found on the internet? Check this out:

# Read a table in from a URL (tab delimited table with row headers) Mydata <- read.table(http://someserver.com/table.txt', header=TRUE) # Display summary (mean, median, min, max, etc.) for each column summary(Mydata)
# Get the standard deviation for the values in column "foo" attach(Mydata) sd(foo)

Learning the command set is a little daunting at first, but the console even does tab completion. If you don't know what a function does, just put a question mark before it. For instance, "?sd" will quickly pull up help for the standard deviation function.

I've only scratched the surface, but there are links below to some R beginner guides which should help you get started. Anyone out there more familiar with the package? Please share any useful links and tips in the comments.

The R Project for Statistical Computing - Link
An Introduction to Statistical Computing in R - Link
Producing Simple Graphs with R - Link

January 30, 2008

UV photography on the cheap

There's an easy way to make a UV pass filter for your camera. It just takes a $5 incandescent black light, a large bottle cap and some duct tape.

For years I've wanted to mess around with UV photography. Unfortunately, all the websites on DIY UV seem to assume an infinite amount of money and access to specialized equipment on my part. There are two things that I don't like, when someone tells me I HAVE to spend a lot of money (quartz lenses starting at $3000) or that i need specialized equipment (Wratten 18A filters, not cheap either).
So I set out to do it my way, and here's my $5 solution to UV wavelength photography.

It's not completely void of visual artifacts, especially at the edges of the photo, but that's what the crop tool is for. As long as you're creative, which you are, you can make it work for you and get really nice results. Save the 3000 bucks for that trip to Europe... you know, where you can exchange it for about 2000 Euro.

Photography in the Ultraviolet spectrum - Link