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November 18, 2008

Backyard beekeeping - 120 pounds of honey

treasure stolen gold
low the sun and busy bees
prepare for winter

We collected honey from our two backyard hives this fall and I've finally finished jarring it. The new hive, split from last year's hive, produced over 20 pounds of honey. This is more than our first hive produced last year, but the older hive was not to be outdone.

Queen Ann, in the second year of her reign, ran a very productive operation. Her daughters produced some of the lightest, most delightful honey I've ever had. The water content is so low that it pours out like a sheet of glass, folding at the bottom like you might expect from taffy.

From Ann's hive, we collected 100 pounds of honey, making the grand total 120 pounds between the two hives. This is the part we harvested. We leave enough behind for the bees to survive on during the long Minnesota winter, which amounts to another 80-100 pounds.

What's incredible is that all of this honey is produced from the flowers, trees, and vegetable gardens within a 2-3 mile radius of the hives. Two years ago, before I began this hobby, I wouldn't have thought this was possible in the city.

If you're interested in starting a backyard hive next spring, this is what you can look forward to. The real challenge of this urban agricultural experiment is to figure out what to do with the harvest.

Previously
Backyard beekeeping - splitting a hive

November 17, 2008

Android hack - a smarter garage door opener

Brad Fitzpatrick created a garage door application for his G1 Android-based Google Phone. This would be noteworthy enough, but the interesting thing about Brad's hack is that it opens the garage door automatically as he approaches his home.

I got it all working. I now have an Android Activity (GarageDoorActivity) which interacts with an Android Service I wrote (InRangeService), letting me start and stop the service's wifi scanning task. The service gets the system WifiManager, holds a WifiLock to keep the radio active, and then does a Wifi scan every couple seconds, looking for my house.

When my house is in range, it does the magic HTTP request to my garage door opener's webserver (HMAC-signed timestamped URL, for non-replayability/forgeability if sniffed) and my garage door opens. Complete with a bunch of fun Toast notifications (like Growl) and Android Notifications (both persistent ongoing notifications for background scanning, and one-time notifications for things like the garage door actually opening).

So when Brad comes home, he starts the application which scans the WiFi network and then opens the garage door as soon as his home network is in range. He even describes an automated version where the phone constantly monitors the network for common scenarios. For instance, your if your phone sees your work network disappear, followed an hour later by your home network appearing, it could safely assume you have come home from work, opening the door without any interaction.

This is compelling support for a fully hackable, open source device. With normal iPhone development, you don't this level of deep access to be able to monitor WiFi connectivity or run an application as a background process.

Brad's released the source code for this one. If this app gives you any ideas, his code might be a good place to start. Just make sure to send us a link to your Android hack when you get your G1 to turn lights on and off when you walk around the house.

Android Garage Door Opener
Download the Java Source

November 16, 2008

Bamboo bike frame

This DIY bamboo frame is absolutely beautiful. Appropriate, since it appears to have hand crafted with love for a significant other. Aaron writes:

The ride quality is TOTALLY SWEET! I realize that I have a bit of a bias, but truthfully I have ridden very few bikes that felt nicer. The bike seems to float over bumpy road surfaces, almost as if it were on giant baloon tires, but nope, they are just 700x23 clinchers pumped hard as rocks. My big worry was that I had not gotten the frame alignment right, but that seems dead on too; riding no-handed is no problem. Oh yeah, and it corners like a fricking roller coaster and it accelerates as fast as anything I've ever ridden. Maybe that's due to the fact that it weighs only 16.5 pounds! I had no idea that it was going to be so light and honestly did a full on "YESSSS!" complete with double fist pump when I hung it on the scale.

There isn't a huge amount of info about the build process, suffice it to say that it began with harvesting carefully selected bamboo and ended with over 100 hours of epoxy and carbon fiber work.

Aaron's Finished Bamboo Bike [thanks, nick]
Details on Making the Bike

Related from Make blog

The Bamboo Bike Project is a collaboration between scientists and engineers at The Earth Institute at Columbia University and a bicycle builder at Calfee Design. The project aims to examine the feasibility of implementing cargo bikes made of bamboo as a sustainable form of transportation in Africa. The ultimate goals of the project are:
1.To build a better bike for poor Africans in rural areas.
2.To stimulate a bicycle building industry in Africa to satisfy local needs.

The Bamboo Bike Project

Making a Carbon Fiber Bike frame

From the pages of MAKE

Working With Carbon Fiber - MAKE:09 p168

November 15, 2008

Myvu Crystal as a wearable head mounted display

Ralf Ackermann sent us a tip on using the Myvu Crystal headset in conjunction with a wearable computer. The Myvu glasses were designed to block out the rest of the world for private iPod video watching, but its VGA resolution and device compatibility makes it pretty suitable for tearing apart.

The consumer myvu crystal HMD (sold as a nice though still somewhat "socially unacceptable" 2 eyepiece video output device for the ipod and other devices generating a PAL/NTSC signal can be modified into a much smaller 1 eyepiece version. This one works very well with a multitude of devices like a Parallax propeller, a Nokia N95 via TV out or a Archos PMA 430. It is thus well suited as the core of "another wearable computer".
For this purpose it might also be combined with the iphone / ipod touch
Xbee IO extension described earlier this week.

Ralf's project is still a work in progress, but it's a reminder that most of the hardware required for a wearable is now commonly available. Considering most of us already carry a sufficient computer (iPhone, N95, G1, etc.) around with us all the time anyway, it's only a matter of time before a HMD design is made cool enough to dodge the social stigma.

Myvu Crystal HMD Modification (Flickr Photo Set)

November 14, 2008

Linux Tip: super-fast network file copy

If you've ever had to move a huge directory containing many files from one server to another, you may have encountered a situation where the copy rate was significantly less that what you'd expect your network could support. Rsync does a fantastic job of quickly syncing two relatively similar directory structures, but the initial clone can take quite a while, especially as the file count increases.

The problem is that there is a certain amount of per-file overhead when using scp or rsync to copy files from one machine to the other. This is not a problem under most circumstances, but if you are attempting to duplicate tens of thousands of files (think, server or database backup), this per-file overhead can really add up. The solution is to copy the files over in a single stream, which normally means tarring them up on one server, copying the tarball, then untarring on the destination. Unless you are under 50% disk utilization on the source server, this could cause you to run out of space.

Brett Jones has an alternative solution, which uses the handy netcat utility:

After clearing up 10 GBs of log files, we were left with hundreds of thousands of small files that were going to slow us down. We couldn't tarball the file because of a lack of space on the source server. I started searching around and found this nifty tip that takes our encryption and streams all the files as one large file:

This requires netcat on both servers.

Destination box: nc -l -p 2342 | tar -C /target/dir -xzf -
Source box: tar -cz /source/dir | nc Target_Box 2342

This causes the source machine to tar the files up and send them over the netcat pipe, where they are extracted on the destination machine, all with no per-file negotiation or unnecessary disk space used. It's also faster than the usual scp or rsync over scp because there is no encryption overhead. If you are on a local protected network, this will perform much better, even for large single-file copies.

If you are on an unprotected network, however, you may still want your data encrypted in transit. You can perform about the same task over ssh:

Run this on the destination machine:
cd /path/to/extract/to/
ssh user@source.server 'tar -cz -C /source/path/ *' | tar -zxv

This command will issue the tar command across the network on the source machine, causing tar's stdout to be sent back over the network. This is then piped to stdin on the destination machine and the files magically appear in the directory you are currently in.

The ssh route is a little slower than using netcat, due to the encryption overhead, but it's still way faster than scping the files individually. It also has the added advantage of potentially being compatible with Windows servers, provided you have a few of the unix tools like ssh and tar installed on your Windows server (using the cygwin linked binaries that are available).

Fast File Copy - Linux!

November 13, 2008

Embed high-res Youtube videos

Here's an example of a normal embedded Youtube video, borrowed from Patti Schiendelman's Gakken Mechamo Inchworm post.

Back in march, it was discovered that when you view a video directly on Youtube, you could add a "&fmt=18" to the URL to enable a higher quality, higher resolution stream which is encoded with the H.264 codec.

To make this work in an embedded video, however, you need a slightly different hack. After pasting the embed code into a blog post, adjust the two video URLs (one in a param tag and one as the src parameter in the embed tag) by adding "&ap=%2526fmt%3D18" to the end.

For example, the above video embed becomes:

And here's the result:

The still frame before the video is played is the exact same over-compressed image, but when a user clicks play, they will get a nice surprise. Instead of 320x240 video encoded with the Sorenson codec, the video will come in at a resolution of 480x360, encoded with the superior H.264 codec.

Embedding High Quality Youtube Videos [via Kottke]
View YouTube in high-res

November 12, 2008

Typeface.js - embedded HTML fonts sans Flash

It's always struck me that font embedding is a huge omission from the web standards toolkit. If you're not satisfied with Georgia and Verdana, you usually need to turn to images or Flash to get the typeface you want. Tools like sIFR have made this a lot more functional, allowing you to write standard HTML and have Flash dynamically replace content in the page, but using Flash just to display HTML text seems a little unsavory. Typeface.js changes all this, providing a standards-compliant way to deliver a rich type experience using HTML and Javascript with no proprietary technologies.

typeface.js uses browsers' vector drawing capabilites to draw text in HTML documents. For a good while, browsers have had support for vector drawing -- Firefox, Safari, and Opera support the <canvas> element (as well as SVG), and IE supports VML.

You declare the particular fonts to use with the font-family attribute, just as you would normally do in CSS. Then you add the "typeface-js" class to any HTML element that should be rendered by the typeface library. The actual embedded font is delivered to the page in the form of another javascript file, which contains the vector information for the particular font face.

The cool part is that any Truetype font can be easily converted to the javascript format using a perl utility that comes with the package (or a web form provided on the typeface.js site). Simply convert any fonts that your page requires and add them to your html using the script tag. The whole process is at least as convenient as building font swfs for use in sIFR, making it a worthy open source alternative.

Typeface.js - HTML/JS Font Embed Library

Previously:
HOWTO - Use rich fonts in your web design with sIFR

November 11, 2008

Make cake in a mug

Wired's how-to wiki gives us "Cake in a Mug," perhaps the greatest thing to come to the microwave since peep jousting:

You're working at home and your mind starts to wander to snack possibilities. There are probably some prepackaged, good-until-the-next-millennium baked items in your cabinet, but you're in the mood for something warm from the oven. Something chocolate. However, your compulsion to work is just strong enough to keep you from leaving the computer long enough to make something from scratch. Guess it'll have to be another stale Twinkie after all.

A single-serving portion of cake. Baked in a microwave. In the mug I mixed it in. Just for me. Right now.

Hello future. You can keep the jetpack.

Make Cake in a Mug

November 10, 2008

Installing Debian alongside Android on the G1

Now that you can run commands as root on the Google phone, you may have been thinking about what else you can do with the device. You know, besides the usual talking, texting, and surfing while driving.

The device is Linux based, sure, but the installed software is relatively spartan and there isn't too much internal space to get dangerous. Thankfully, Jay Freeman wrote a nice guide for installing a more complete Linux distribution on the device, right alongside Android.

The main thing I've so far seen on this matter have been a few attempts to get busybox on there. I, however, think we can go a lot further: following the instructions in this article will end you up with a full distribution of Debian, one of the most highly respected Linux distributions, and the ability to install almost anything you want.

To do this, we need to think through a few of the details of getting this sort of thing running on the G1. The first question: where do we put it? The device has some internal flash, but it isn't really enough: only 128MB to share with the OS and other applications.

We therefore turn our attention to the much more reasonably sized microSD card, a format which lets us get up to 16GB of space.

Debian & Android Together on G1

November 9, 2008

SlugPower - Linux controlled power switch

Phil Endecott has done a bit of hacking with the Linksys NSLU2 "Slug", the low-power network storage device which runs Linux under the hood. His SlugPower project is a switched outlet that can be controlled from the Slug. This enables his print server to power up the printer when it needs to be printing, and automatically cut power to the device when it's not in use.

This page describes the hardware and software design of a printer power switch controlled over USB from my Linksys NSLU2, aka Slug. The unit can, however, be controlled from any Linux box, and can switch anything, not just printers.
My NSLU2 acts mostly as a file and print server. I can go for weeks without printing anything, so I want to keep the printer switched off when I'm not using it (it takes about 4W while idle, which must be more than 99% of its total energy consumption). But it's upstairs, and I don't want to have to go up and down stairs once to switch it on and again to collect my printing. So I decided to get a power switch.

Remote power switches are pretty common in server rooms, but they are costly. This is a pretty affordable way to control the power to any device from anywhere in the world.

SlugPower - A Slug-Controlled Power Switch
Phil Endecott's Slug Projects
NSLU2-Linux

November 8, 2008

Play backed-up Wii games

If you're prone to scratching or loosing your Wii games, there's a way to back up your games to DVD and play them later. An alpha copy of Wii Backup Loader was leaked to the public a while back, and combined with the hack to enable your Wii to run homebrew, this will allow your Wii to play burned DVDs without a modchip.

Instructable user thundaboy1047 put together a guide for downloading and installing the necessary software.

Run Backups on any Wii Without a Modchip [via Lifehacker]

Quick workaround for the T-Mobile G1 root shell bug

Android Terminal Emulator

Update 1: It looks like the process respawns itself after you type exit, so Ed's suggestion of typing cat is the best one. So instead of typing exit, just type cat when your phone first boots up; this should render the rogue root shell harmless.

Update 2: I woke up this morning to find that an update was out for the G1 that fixes this. That happened pretty quickly (the last update trickled out to users pretty slowly).

I was freaked out about this awful bug in Android. Basically, there's a root shell running that executes every keystroke you type on the keyboard--as the root user, no less. The proof is simple, as Ed Burnette writes:

open the keyboard tray on your G1, ignore anything you see on the screen, and type these 8 keystrokes: <return>-r-e-b-o-o-t-<return>. Poof, your phone will reboot. This only works on a real phone, not in the emulator, and only with firmware version 1.0 TC4-RC29 and earlier.

Ed suggests typing cat to lock up the shell, ~~but here's a way you can completely shut down the rogue shell. Instead of typing reboot, type exit. That will shut the rogue shell down.~~ Ed's suggestion works by causing the shell to run the cat utility, which simply repeats whatever is fed into this. Because this rogue shell isn't tied to any terminal output, this repeated output won't go anywhere.

Each time you boot the phone, use the cat trick. If you're worried about typing random characters into the phone, press the red key, then the menu key. I've found that you can type these commands on the "Draw pattern to unlock" or "Press menu to unlock" screens. You'll need to do this until T-Mobile pushes out the update that fixes this (based on how the last update rolled out, it seems to take a week or more for them to distribute fixes to everyone).

If you want to see the offending process, run the command ps in the Terminal Emulator application (available for free in the Android Market), and you'll see a list of all running processes on the phone. At least on my phone, the rogue sh process is always started as process id 26. So if you run ps, you'll see something like this (output slightly abridged):



root     25    ... krfcommd

root     26    ... /system/bin/sh

system   27    ... /system/bin/servicemanager

Although I suggested in a previous version of this post that you could type exit instead of cat, that won't help, because Android's init.rc script respawns the rogue shell. For this reason, using the kill command to kill it won't work either. The best we can do for now is just wedge it up with cat.

If you had the time and inclination, you could edit the init.rc file that's the source of the problem. The only trouble there is that it's not on a normal filesystem, but in a ramdisk image that's unpacked each time you boot up, so you'd have to get your hands really dirty to make that fix.

November 7, 2008

Hand gesture multitouch using only a webcam

Andy Wilson of MS Research—a name you may recognize from yesterday's $1 gesture recognition post—is responsible for a number of pretty unbelievable projects involving image processing and human computer interfaces. It's the sort of stuff that really blurs the boundaries between real and digital environments.

I was blown away by the video above, in which Andy demonstrates a multitouch-like hand gesture interface. Get this. It uses only a standard webcam.

The webcam is positioned to watch your keyboard and by simply making a pinching gesture with your thumb and index finger, you can grab and move objects on the screen, or rotate them by twisting your hand. Pinching with two hands, you can control two separate points on the screen, allowing you to easily perform more complex zoom and rotation actions by pulling your hands apart or moving them relative to each other.

I haven't seen source for this anywhere, but he does describe the technique, which is quite clever. By subtracting the background and examining the topology of the remaining image (just the solid background and your hands), you can easily determine how many shapes are made by the background.

With fingers unpinched, the background is a single shape, albeit with a hand shaped isthmus pushing into it. When you pinch and form a circle with your thumb and forefinger, things change. A little island is created in the middle of your fingers and the background becomes two distinct shapes. The position and rotation of the inner shape provides you enough information to control objects on the screen.

Hand Gesture Multitouch [via Procrastineering]
Andy Wilson

Previously:
Gesture recognition for Javascript and Flash

November 6, 2008

Gesture recognition for Javascript and Flash

The "$1 Recognizer" is a simple gesture recognition algorithm created by Andy Wilson from Microsoft Research and Jacob Wobbrock and Yang Li from the University of Washington.

By simple, I mean that it's under 100 lines of code that you can quickly add to your application to give it gesture recognition capabilities.

To enable novice programmers to incorporate gestures into their UI prototypes, we present a "$1 recognizer" that is easy, cheap, and usable almost anywhere in about 100 lines of code. In a study comparing our $1 recognizer, Dynamic Time Warping, and the Rubine classifier on user-supplied gestures, we found that $1 obtains over 97% accuracy with only 1 loaded template and 99% accuracy with 3+ loaded templates. These results were nearly identical to DTW and superior to Rubine.

It works by using a simple 4-step process, which basically amounts to:

Resampling the recorded path into a fixed number of points that are evenly spaced along the path
Rotating the path so that the first point is directly to the right of the path's center of mass
Scaling the path (non-uniformly) to a fixed height and width
For each reference path, calculating the average distance for the corresponding points in the input path. The path with the lowest average point distance is the match.

What's great is that the output of steps 1-3 is a reference path that can be added to the array of known gestures. This makes it extremely easy to give your application gesture support and create your own set of custom gestures, as you see fit.

Give the demo a try. I was pretty surprised at how accurate the results were, even with single-temple custom gestures that I quickly scribbled out.

$1 Gesture Recognizer - Examples and Source (Javascript, Actionscript, and C#)

Gestures without Libraries, Toolkits or Training:
A $1 Recognizer for User Interface Prototypes (PDF)

November 5, 2008

Programming DNA

At last year's Chaos Communication Congress conference, Drew Endy presented a lecture titled "Programming DNA - A 2-bit language for engineering biology". He does a fantastic job of laying out the state of bio-engineering technology, including some of the potential applications and societal challenges, all from a hacker perspective.

Genetic engineering is now a thirty year old technology. For reference, over a similar period of time, modern computing machines went from exclusive objects used to design weapons of mass destruction, to the now ubiquitous panoply of personal computing devices that support mass communication and construction. Inspired by this and many other past examples of the overwhelmingly constructive uses of technology by individuals, we have been working over the past five years to develop new tools that will help to make biology easy to engineer. We have also been working to foster a constructive culture of future biological technologists, who can reliably and responsibly conceive, develop, and deliver biological technologies that solve local problems.

This talk will introduce current best practice in biological engineering, including an overview of how to order synthetic DNA and how to use and contribute standard biological parts to an open source collection of genetic functions. The talk will also discuss issues of human practice, including biological safety, biological security, ownership, sharing, and innovation in biotechnology, community organization, and perception across many different publics. My hope is that the conferees of 24C3 will help me to understand how to best enable an overwhelmingly constructive hacker culture for programming DNA.

Programming DNA - 24th Chaos Communication Congress

November 4, 2008

Live via hologram

During tonight's election coverage, CNN pulled out some deep tech, displaying Jessica Yellin live via hologram. I looked closely and wasn't even able to see the R2 unit behind the scenes.

<update>
My original impression of how this works is below. A comment from Eric suggests that this might actually be a real hologram that Wolf can see in person, and not a live bluescreening effect. More on this at the end of the post.
</update>

From what I can tell (and I could be wrong), this is done using a combination of technologies, most of which you could simulate at home if you could be satisfied using standard equipment, some careful camera work, and post production techniques instead of the real-time hardware and networked camera equipment CNN is rocking.

The person is recorded inside of a blue or green tent surrounded by an array of cameras that are able to catch several angles at once, presumably with each camera partnered with a real camera on the studio stage. The appropriate holo-camera feed is chosen depending on the real studio camera being used, and the holo camera is networked and synced to move exactly with its partner camera in the studio. This allows the hologram to shift perspective appropriately as the studio camera scoots around the stage. You might compare this to how the virtual first down line is tweaked in real-time to fit the various camera positions in a football game broadcast, except in this case it's not a generated asset, it's a live video feed that's carefully filmed to be at the exact perspective.

Finally, using traditional keying/blue-screen techniques, the tent background color is alphaed out of the feed and the video is overlayed on top of the studio feed, leaving the keyed-out hologram correctly perspective positioned on the final output.

There are two final added touches that make this pretty convincing. One is the red circle on the floor. My best bet is that it's real and created with a red light from above in the live studio feed. The second is the person-to-person conversation. Wolf Blitzer is a pretty good actor - there's no way he's actually seeing the hologram in front of him.

Or can he? Eric points us to the Musion Eyeliner and Cisco Telepresence technology that can display what appears to be a fairly high-fidelity hologram in a stage environment. Here's a video that shows how such a system would be set up:

I remain a bit unconvinced that this is actually what's going on, mostly because of the full 180 degree camera POV that was used in the CNN version, but doesn't seem possible with the Musion system. What are your thoughts? Please post them in the comments.

Anyone care to make their own hologram video with a moving camera? It'd be a bit of a challenge using consumer equipment, and I'm not sure what software you'd use if you didn't have something like After Effects, but it'd be pretty fun to see. For inspiration, here's a decent one done with a fixed camera position:

CNN Hologram Interview [via MAKE]
Real Life R2D2 Hologram

Cisco Telepresence Demo On Live Stage
Musion Eyeliner Hologram Projection System

November 3, 2008

Top 5 election day mashups

Aside from the politics, opinions, and issues involved in this election, I've been really interested in how the current state of web technology, survey data, online conversation and public information would be merging together into web applications and utilities for the growing digital electorate.

From finding a voting location, to enabling countrywide real-time political conversation (by people, not pundits), to monitoring live election results, and even reporting quality of service measurements at poll stations, below are my favorite examples of the web working hard to improve the democratic process.

Where And How To Vote

Google is providing what is essentially a voting howto map that will help you with directions to your voting location as well as information about your state's election regulations. After you type in your address, you'll be shown the location of your voting precinct, as well as useful links to registration information for your state. Many states allow "day of" voter registration, so if you haven't already registered and you'd like to vote, it's worth checking out.

Map of 2008 Voting Locations and Instructions

Tweet Your Vote

It's simple. We voters are using Twitter and other texting tools to report on how the vote is really going during this election, and we're urging everyone to use the common word (or "hashtag" in Twitter lingo) of #votereport as they do so. If that happens, we'll all be able watch on maps and graphs how the election is going across the country.

To participate, you'll want to Tweet details on your voting experience, including your location, wait time, quality of experience, and any problems that you ran into. Useful hashtags include: #[zip code], #wait:[minutes], #good or #bad, and #machine or $reg (for machine or registration problems). For example:

#votereport things are #good in #55404 with #wait:30

This will let local volunteer monitors know that things are functioning well in the 55404 area code and that the wait time at the polls is only 30 minutes. More information is available at the Twitter Vote Report web site, and in the video above, including ways to report serious issues as well as reporting status by phone.

Twitter Vote Report

Monitor Poll and Survey Data

You can monitor trend estimates for the presidential, senate, and house elections on pollster.com. The map data provides a working estimate of the election outcomes by calculating regression trendlines based on available survey data.

In most cases, the numbers are not an "average" but rather regression based trendlines. The specific methodology depends on the number of polls available.

If we have at least 8 public polls, we fit a trend line to the dots represented by each poll using a "Loess" iterative locally weighted least squares regression.
If we have between 4 and 7 polls, we fit a linear regression trend line (a straight line) to best fit the points.
If we have 3 polls or fewer, we calculate a simple average of the available surveys.

Clicking on a state will give you more information about the poll data, as well as the computed trendline that forms the basis of the predicted outcome.

Pollster 2008 Election Polls

Tweet Your Opinions

Twitter is running a special Election 2008 filter that lets you track opinions and conversations about the presidential election through the lens of users' Tweets. Basically, any time you use the word Obama, McCain, Palin or Biden in a tweet, it will show up in the live monitor. The site uses AJAX requests to pull in successive batches of updates and display the messages in almost real-time. You can filter by a particular candidate, or just watch the whole passionate conversation roll by, assuming you can read fast enough.

Twitter Election 2008 Stream

View Live Election Results

Google is also providing live election results in a map gadget. As precincts begin sending in data, the map above should change to reflect the current reports. You can embed this in your own page by following the link below. The gadget allows you to customize the embed code to track either the presidential, house, or senate election.

2008 Election Results Gadget

Send Us Your Favorite Election Hack

Do you know of any voting mashup hacks or tools that I've missed? Please add them to the comments!

(Keep in mind that we want to hear about your favorite election tech, but please reserve any political discussion for a more appropriate site.)

November 2, 2008

Telescope control with stepper motors

If you want to take a stab at amateur astrophotography, or have a telescope with "goto" or auto tracking capability, you either need to make a substantial investment in hardware and software, or you can built your own computer controlled mounts and use a variety of open source telescope guidance software packages. I caught the following discussion on the Twin Cities Robotics Group's mailing list today. Robot hacker Bruce Shapiro posed this question to the list:

I've started another one of my "bits to bots" classes-- this time out here at the local art center, and with adults. One of the students is very keen on the idea of stepperizing his telescope, and already has put in a lot of effort rolling his own stepper drives. I seem to recall that this is a common goal, and that there is both some decent free/shareware out there that will control your motorized scope, as well as plans for the retrofit. But a quick search just turned up a bunch of individuals' pages that didn't have the pizzazz I think I remember once seeing. Basically, I'd like to save him from reinventing this wheel. I suspect some of you may be able to point us in the right direction?

The quick response from list member Alan Kilian was to check out Mel Bartels' BBAstroDesigns site. It contains a wealth of information for hobbyists looking to build a DIY computer operated telescope. A lot of the information is for Dobsonian mounts, and you'll find howtos for adapting your telescope, building the stepper control electronics, and software for controlling the rig from a PC. Depending on what you choose to do, you can completely automate your scope for somewhere between $100 and $500.

BBAstroDesigns - Computer Operated Telescopes
Mel Bartels' Telescopes and Telescope Making
Twin Cities Robotics Group

Illustrated Guide to Astronomical Wonders: Get it now at the Maker Shed

November 1, 2008

CSSHttpRequest - cross browser AJAX without JSON

Because XMLHttpRequest only functions in a same-origin model, the main alternatives have been to either proxy the XML request server-side, or transfer javascript arrays via JSON (since cross-domain script calls are allowed). CSSHttpRequest is another method for performing cross-domain AJAX-style requests, but instead of running loading a remote Javascript file, CSS is used as the transport, and data is encoded inside of urls in @import statements.

A request is invoked using the CSSHttpRequest.get(url, callback) function:
    CSSHttpRequest.get(
        "http://www.nb.io/hacks/csshttprequest/hello-world/",
        function(response) { alert(response); }
    );
Data is encoded on the server into URI-encoded 2KB chunks and serialized into CSS @import rules with a modified about: URI scheme. The response is decoded and returned to the callback function as a string:
    @import url(about:chr:Hello%20World!);
CSSHttpRequest is open source under an Apache License (Version 2.0).

This is a pretty cool alternative—it seems to be a much safer way to do things than blindly executing javascript from servers not under your control. It's somewhat like what XMLHttpRequest could have offered if it weren't limited by the same-origin policy (though in a more roundabout way).

It still begs the question: why on earth is XMLHttpRequest limited by a same-origin policy, especially when it forces developers to adopt more dangerous methods for cross domain communication?

CSSHttpRequest

October 31, 2008

The Skein hash function and Threefish block cipher

The National Institute of Standards and Technology is holding a competition to design a new hash function to replace the current SHA family of functions and become SHA-3. The deadline for submissions was today, and the submissions will be evaluated over the coming years until a final proposed standard is made in 2012. Bruce Schneier posted some information about his team's entry, Skein, and the whole selection process:

NIST is holding a competition to replace the SHA family of hash functions, which have been increasingly under attack. (I wrote about an early NIST hash workshop here.)

Skein is our submission (myself and seven others: Niels Ferguson, Stefan Lucks, Doug Whiting, Mihir Bellare, Tadayoshi Kohno, Jon Callas, and Jesse Walker).

...

The selection process will take around four years. I've previously called this sort of thing a cryptographic demolition derby -- last one left standing wins -- but that's only half true. Certainly all the groups will spend the next couple of years trying to cryptanalyze each other, but in the end there will be a bunch of unbroken algorithms; NIST will select one based on performance and features.

The Skein hash function is based on a the Threefish block cipher, which is also released as part of the submission. Source has been released to the public domain, which you can download from the Skein website.

Schneier on Security: The Skein Hash Function
Skein Submission Paper - Design, Usage, and Preliminary Cryptanalysis (PDF)
The Skein Hash Function Family Website