WordPress 2.7 Upgrade In One Line

December 10, 2008 by Eliot 43 Comments

BadPoetry WordPress 2.7 has just been released and features a complete interface overhaul. Hack a Day runs on WordPress MU hosted by WordPress.com, so we got this update last week. We run standard WordPress.org on all of our personal blogs though. We recommend it because it’s free, has a massive userbase, and if you host it yourself, you can do whatever you want with it.

To make the upgrade process as simple as possible (and for the sheer rush of ‘rm -rf’), we use a one line command.

$ curl http://wordpress.org/latest.zip -o "wp.zip" && unzip wp.zip && rm -rf ./wordpress/wp-content/ && cp -r ./wordpress/* ~/www/

curl downloads the latest version from wordpress. unzip unpacks all of the files into a directory called ‘wordpress’. rm -rf removes everything in the ‘wp-content’ directory. Otherwise, you will overwrite your images, themes, and plugins. cp -r copies everything to your http document root, overwriting the previous install.

Naturally, you should back up your current install and database beforehand. We tend to use the one-liner with reckless abandon. If you’re wondering about the terseness, it was designed to fit inside the 140 character limit of Twitter.

[Thanks, Chris Finke]

Edge-lit Holiday Cards

December 10, 2008 by Eliot 8 Comments

edgelit

Got 30 minutes for a holiday project and don’t want to get wrangled into some sort of decoupage disaster? Evil Mad Scientist Laboratories can show you just how easy it is to do edge lighting effects. Pictured above are three holiday cards constructed using scored plastic. You can use many different types of clear plastic for this, not just acrylic. The lighting is just an LED on a coincell. Black tape is used to prevent light leaking from the edges. The red and green version above is two stacked layers. This looks like something fun to scale up for a larger project or just to kill some time.

22″ Binocular Telescope

December 9, 2008 by Caleb Kraft 16 Comments

binocular

This is the worlds largest known visual binocular. Why binocular and not just a regular telescope? Well, it all has to do with clarity. Apparently when you can use both eyes, you can see much more detail and pick up light better. The author states in one story that he was able to see a spiral galaxy clearly with a binocular telescope, but couldn’t see it at all with a monocular telescope of the same power.

There is information on several models on the site. Look in the right hand column as well for useful links to parts distributors.

[via Hacked Gadgets]

Genetic Programming

December 8, 2008 by Eliot 46 Comments

monalisa

[Ron Alsing] wanted to try out some genetic programming, so he created a simple test problem: Could you render the Mona Lisa using just 50 semitransparent polygons? The program starts with a random DNA sequence. It then mutates and compares itself to the original image. If the mutation is closer, it becomes the new sequence. The final image he shows looks pretty good after 904,314 iterations.

[prunesquallor] pointed out a genetic algorithm project of his own. It’s a flash program to evolve a car. The car tries to get as far as possible on a set terrain without the passenger circles hitting the ground. The wheel size and positions can change along with the spring length, constant, and damping. A graph tracks the best performance along with the mean. He’s planning on building a version that lets you change the parameters.

[via Waxy]

Simple Laser Projector

December 8, 2008 by Eliot 21 Comments

laserscanner

[kap4001] built what has to be the simplest laser scanner possible. It’s two servos strapped together with zip ties plus a 5V laser module. They’re connected to a Pololu serial servo controller. The laser is pulsed by switching the DTR line. You could use it to draw images like the one above… except that’s an 85 second exposure.

Arduino Shield Scaffold

December 6, 2008 by Eliot 11 Comments

arduinoshield

[Garrett] from macetech has been prototyping shields for the Arduino development platform. Arduino’s have an inexplicable nonstandard spacing between two of the banks of output pins. This means that you can’t use regular perfboard with them. To make the design process quicker, [Garrett] has put together an Eagle file that just includes the male header pins. The file also has a line indicating the tall lower board components so you can avoid creating shorts.

Arduino Switch Box

December 4, 2008 by Eliot 12 Comments

arduino_switch

When you’re prototyping a new project, sometimes all you need is a switch. The folks at oomlout were tired of constantly having to rewire things, so they built a universal switch box for the Arduino. It has five potentiometers plus three switches. They’ve put together a software package that monitors the switches and can show you a live view of the knob positions. Have a look at the video below for a demo.

The writeup actually hints at what we can only assume is the next kit they’re releasing: a robot arm. Continue reading “Arduino Switch Box” →