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February 29, 2008

MAKE Primer - Electronic test equipment

Electronic Test Equipment by Tom and Wendell Anderson. See and understand what's happening inside a circuit. Page 158 - MAKE 10. Read this article now in the MAKE digital edition.

Or get MAKE 10 from the Maker store and/or subscribe to MAKE (use code CMAKE for $5 off USD).

You can view all our in depth Primers from MAKE here too.

Single character commenting

It's a pretty common practice to comment and uncomment big chunks of code during the development and testing of software. Here's an odd little hack from the ajaxian blog that can make this a little easier for blocks that you're constantly flipping on and off during development.

For C style comments, the following will be commented out:

/* if ( foo == bar ) { dosomething(); return(); } // */

And the addition of a single '/' will uncomment the block:

//* if ( foo == bar ) { dosomething(); return(); } // */

In languages that don't have the single line comment, such as CSS, you can do the same thing with only the block level comments.
Commented:

/*/ min-height:100px; /**/

Uncommented:

/**/ min-height:100px; /**/

You are probably talking to your screen right now, saying, "hey Jason, that commenting trick is marginally useful at best." I can only respond by reminding you that every keystroke is a beautiful and unique snowflake that must be cherished and never wasted.

A neat commenting trick - Link

Hack Your Brain - Best of Weekend Projects

ipod|mp4|mov|hd-appletv|3gp|3g2|pdf|itunes

This weekend on Best of Weekend Projects with Bre Pettis, learn how to hack your brain by making Mitch Altman's Brain Machine! It flashes LEDs into your eyes and beeps sounds into your ears to make your brain waves sync up into beta, alpha, theta, and delta brainwaves!

Mitch invents cool things that make the world a better place. He's well known for the TV-B-GONE and this brain machine is his latest project. One of the cool things about this project, is that it builds on an open source project. Mitch used Lady Ada's open source MiniPOV and switched out LEDs and added new capacitors and resistors and then rewrote the firmware to make it into the brain machine. It's super cool when people make hardware open source so that others can work with it!

513591733 E18C33A406

Make sure to take pictures of your build and of you in your brain machine and upload them to the Make: flickr pool.

Get the podcast and pdf downloaded automatically in itunes. - Link

Hacking VGA with Arduino

Cool visualization on a monitor via Arduino

An arduino board is controlling the RGB lines of a VGA connection to an LCD monitor. However, the horizontal and vertical sync lines are being generated by a proper computer.

- Code and info on Little-Scale - Link

Related:

Arduino TV - Link

In the Maker store:

"Critter & Guitari" Cellular Automata Video Synthesizer Kit - Link

Digital Camera Interface

Getting a computer to "talk" with a CMOS camera can be difficult, if not impossible, at times. The site has links to PDF files that contain the schematics and theory of operation. There is also a link containing all the code. It's a nice solution to a common problem.

The aim of this project is the development and construction of an interface between a CMOS camera and a computer. This interface allows a user to get images from the camera, to change some of the properties of the camera as brightness, luminance, etc from a computer. Also some image process is implemented allowing the camera to track white objects and follow them with a servomotor. The interface was implemented using the Atmel AVR ATmega16 microcontroller.

Digital Camera Interface - Link

Arduino compatible breadboard

This is a nice little tutorial on building your own Arduino compatible breadboard. The heeart of the board is an AMTEL8 AVR and breakout board from SparkFun. It is a fairly easy build, but if you just want to jump right into programming pick up a completed version in the MAKE store! - Link

Wiimote controlled curtains

Controlling your curtains via a Wiimote is either laziness at its best, or a great solution for those with mobility issues. The curtains can be controlled from a wall switch, but even that could be problematic for some people. This could definitely be a great help for some people. - Link

Related:

Track fingers with the Wiimote - Link

February 28, 2008

Detecting forged photos algorithmically

John Graham-Cumming posted an automated tool for detecting "Clone Tool" Photoshop forgeries. Photojournalism ethics issues (LInk, Link) aside, John had some ulterior motives:

I was motivated to work on this program by greed (or at least my never-ending love of having a little flutter on things). Best of the Best runs spot-the-ball competitions in airports to win very expensive cars. But they also run the same competition online. That meant I could get my hands on the actual image used... could I process it to discover where the ball had been removed? (In reality, this isn't the right way to win because the actual ball position is not governed by where it actually was, but where a judge thinks it was).
Would it be cheating if I could? Apparently not, the competition rules say I should use my skill and judgment in determining the ball position. Surely, skill covers my programming ability.

So, I went looking for tampering algorithms and eventually came across Detection of Copy-Move Forgery in Digital Images written by Jessica Fridrich at SUNY Binghamton. The paper describes an algorithm for detecting just the sort of changes I thought I was looking for.

Essentially the algorithm cuts the image into a bunch of 16x16 chunks and runs each chunk through a discrete cosine transform. The DCTed chunks are compressed and sorted, and the algorithm looks for multiple matching chunks that were shifted the same direction and distance, highlighting the source image if a large number of matches are found.

Another blogger, jjwiseman, released a speed optimization for John's code, which he successfully used on the infamous Adnan Hajj Reuters images. While the algorithm is able to detect this style of manipulation, it's noted that it has a habit of returning false positives in images with a blurry background.

That said, it'd be pretty interesting to run this through a big database of news photos and see what turns up.

Detection of Copy-Move Forgery in Digital Images - Link (PDF)
John Graham-Cumming's Clone Tool Detector - Link
Protecting Journalistic Integrity Algorithmically (jjwiseman's update) - Link

Simple walking bot

Matt Mets made this simple servo-controlled walking bot which uses a Barebones Arduino to walk, one leg at a time. Source code included. - Link.

Vibrobot from a speaker and pull-cord toy

Randy made his own version of the Bristlebot, but with a speaker and pull cord. Excellent, and with renewable propulsion! I like the little resistor antlers/feelers - Link.

Related:

HOW TO - Make a Bristlebot a tiny directional vibrobot made from a toothbrush! - Link.

Bristlebot racing snail - Link.

Readybot will clean your kitchen

Dishwashers are so last week. I want a Readybot! Not only will this robot clean the dishes, it will tidy up the whole kitchen and you don't even have to give it an allowance. Hopefully this will become a reality soon, because I need one...NOW! - Link

Claytronics nanoscale robot designs

You may know of Claytronics (aka programmable matter) - the use of reconfigurable nanoscale robots to form shapeshifting objects.
Researchers at Carnegie Mellon University have proposed several basic robotic designs as possible foundations for claytronics, including:

Planar catoms test the concept of motion without moving parts and the design of force effectors that create cooperative motion within ensembles of modular robots.
Electrostatic latches model a new system of binding and releasing the connection between modular robots, a connection that creates motion and transfers power and data while employing a small factor of a powerful force.
Stochastic Catoms integrate random motion with global objectives communicated in simple computer language to form predetermined patterns, using a natural force to actuate a simple device, one that cooperates with other small helium catoms to fulfill a set of unique instructions.
Giant Helium Catoms provide a larger-than-life, lighter-than-air platform to explore the relation of forces when electrostatics has a greater effect than gravity on a robotic device, an effect simulated with a modular robot designed for self-construction of macro-scale structures.
Cubes employ electrostatic latches to demonstrate the functionality of a device that could be used in a system of lattice-style self-assembly at both the macro and nano-scale.

Interesting to see these different approaches at such an early stage of the technology. Now to wait 20 or so years and see which design comes out on top.

Videos and detailed info @ Carnegie Mellon - Link

Shape-shifting robot forms from magnetic swarm @ New Scientist - Link

Related:
Claytronics - Link

Robotic dream playback

"Sleep Waking" by Fernando Orellana and Brendan Burns presents a new way to look back on one's dreams. EEG, EKG, REM, and various other physical data is logged during the subject's sleep and then later used as the script to direct robotic action -

The eye position data we simply apply to the position the robot's heads is looking. So if my eye was looking left, the robot looks left.
The use of the EEG data is a bit more complex. Running it through a machine learning algorithm, we identified several patterns from a sample of the data set (both REM and non-REM events). We then associated preprogrammed robot behaviors to these patterns. Using the patterns like filters, we process the entire data set, letting the robot act out each behavior as each pattern surfaces in the signal. Periods of high activity (REM) where associated with dynamic behaviors (flying, scared, etc.) and low activity with more subtle ones (gesturing, looking around, etc.). The "behaviors" the robot demonstrates are some of the actions I might do (along with everyone else) in a dream.

What? No electric sheep? - Link

Ladybug maintenance bot

She may look like one, but don't call her a "bug" - The "Lady Bird" autonomous robot was introduced to Western Japan's highway rest stops in November of 2007 to maintain restroom cleanliness as well as friendliness -

In addition to cleaning, Lady Bird can engage in simple conversation with restroom users, thanks to microphones in its "antennae," speech recognition capabilities and a voice synthesizer. The robot has access to the latest information about traffic conditions on nearby roads, which it can relay to anyone comfortable enough to ask.

I believe I might feel less than "comfortable" if I met Lady Bird during a late night, highway bathroom break. - Link

Related:

Jumbo cleaning robots - Link

Excel Hacks: Display a "please wait" message

Excel Hacks, 2nd Edition Cover

Here's Hack #111, Display a "Please Wait" Message, from David and Raina Hawley's Excel Hacks, 2nd Edition. Millions of users create and share Excel spreadsheets every day, but few go deeply enough to learn the techniques that will make their work much easier. Yet there are many ways to take advantage of Excel's sophisticated capabilities without spending hours on advanced study. In Excel Hacks, you'll learn how to:

Reduce workbook and worksheet frustration--manage how users interact with worksheets, find and highlight information, and deal with debris and corruption.
Analyze and manage data--extend and automate these features, moving beyond the limited tasks they were designed to perform.
Hack names--learn not only how to name cells and ranges, but also how to create names that adapt to the data in your spreadsheet.
Get the most out of PivotTables--avoid the problems that make them frustrating and learn how to extend them.
Create customized charts--tweak and combine Excel's built-in charting capabilities.
Hack formulas and functions--subjects range from moving formulas around to dealing with datatype issues to improving recalculation time.
Make the most of macros--including ways to manage them and use them to extend other features.
Use the enhanced capabilities of Microsoft Office 2007 to combine Excel with Word, Access, and Outlook.

Hack #111: Display a "Please Wait" Message - Link

Related:

Excel Hacks, 2nd Edition @ the Maker Store - Buy now
Excel Hacks, Second Edition--New from O'Reilly: Hook Up with Excel Expert Hackers - Press Release

Rules for Roboticists

In honor of Robot Day here on MAKE, I've posted my "Rules for Roboticists," from my 2004 book Absolute Beginner's Guide to Building Robots. It's a playful list of operating principles, rules of thumb, and words o' wisdom about bot building. The piece is accompanied by robot scientist "trading cards," illustrated by Mark Frauenfelder, for the book.

11. A roboticist should know when to come back later (A.K.A. "The Kenny Rogers Rule")
When you're building anything, especially something as complicated as a robot, the build can sometimes get ugly. If you try to force your way through, you can often dig yourself into an even deeper hole. So here's what you do: "Put the soldering iron down. Step away from the steaming robot entrails!" You'll be amazed at what an hour away, vegging in front of the TV, rolling around on the floor with the cat, or sleeping on your problem will do. It almost never fails. Here's a corollary: The extent to which you don't want to drop what you're doing and take a break ("I know I can fix this, damn it!"), is inversely proportional to the extent to which you need a break. Why is it the Kenny Rogers Rule? Cause "you got to know when to hold 'em, know when to fold 'em, and know when to walk away..."

Rules for Roboticists - Link

Cute bot alert!

From the MAKE Flickr pool

. . . not autonomous, not motor driven, not even powered - just plain cute.

Farnea's Audrey robots #1, - Link & #2 - Link

Related:
DANGER . . . CUTENESS SENSORS . . . OVERLOADING!!
Homemade robot costume - Link

LEGO unicycle robot keeps its balance

This Lego Unicycle Robot balances on one wheel and uses RCX Lego Mindstorms bricks with 4 sensors and three tires to maintain its balance. It stays upright by directly powering the wheel. Really nice video above of the whole thing in action.

Yet Another LegWay - [via]

Send SMS to control Robosapiens

This project by Tim Redfern allows onlookers to send SMS messages to Robosapien robots who respond with some impressive dance moves. The system uses a custom built, downloadable Xtra for (Macromedia/Adobe) Director called "UIRT XTRA" that is free from the site below. Check out the video.

Dancing Robosapiens - Link, UIRT Xtra Download

Heathkit HERO

Back in the 1982, Heathkit released the HERO 1 educational robot. HERO 1 had a Motorola 6808 CPU and 4k of RAM on board. He came equipped with motion, light, sound and sonar ranging sensors. You could even add an optional arm attachment and max out his capabilities.
Taking a cue from the success of the HERO 1, Heathkit's consumer division released a simplified version, the HERO Jr - with half the ram of it's predecessor and a lower pricepoint. Later still, the expandable, speech capable HERO 2000 was released to the educational market. By far the most advanced iteration, the 2000 would be the last training robot released by the company. That is until now - Heathkit is planning to release a reincarnation of HERO, the HE-RObot:

Popular Science explains -

Built on a Mini-ITX mobo with Intel Core Duo microprocessor and using Windows XP for its operating system (unlike the model 914 PC-BOT which can be outfitted with Ubuntu), HE-RObot is being built and priced towards the educational market. A market that sorely needs a sophisticated robot platform. The hobbyist DIY market, on the other hand, could suffer from sticker shock. The HE-RObot's 914 PC-BOT counterpart is priced from $5,000 - $8,000 which could make the HE-RObot a tough sell to even the most rabid roboticist.

Personally, I prefer the boxy look of the old model anyway. (Instead of this boxy looking new version) - [via] Link

Detailed HERO History on Robotgallery.com - Link

Check out Donnie V. Savage's site for a bunch of relevant build info - Link

Related:

Heathkit schematic diagram archive - Link