Ken Moore, a user experience designer at Google, created a very convincing Theremin simulator using a Wiimote and a Roland JV-1080 synth.

I've seen a few Theremin simulators that use accelerometer data, in both Wiimote and iPhone form, but this is the first I've seen that does a good job of recreating an authentic Theremin experience in all its 50s sci-fi awesomeness. Using some IR gloves and the Wiimote's CCD, one hand's horizontal movement controls pitch and the other hand's vertical movement controls volume.

At just $35, the Wiimote is an AMAZING piece of technology. It has an infrared camera in it which tracks the position up to 4 infrared light sources. So I bought a pair of leather gloves, wired up a couple infrared LEDs to 1.5 volt batteries, and poked an LED through the tip of the index finger of each glove.

Then, I connected my Wiimote to my computer (the Wiimote also supports Bluetooth connections): building on top of Brian Peek's Wiimote hacking software library, I wrote a program which detects the two infrared gloves and converts the vertical position of the left hand to volume, and converts the horizontal position of the right hand to pitch. That information is then sent via MIDI to the synthesizer which creates the actual sound.

One of the more interesting possibilities with this setup is that by adjusting the synthesizer, you can use a Theremin-like interface to control a huge number of effects, not just the standard sci-fi sine wave. I wonder if Léon Theremin would approve.

Wii Theremin

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)

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

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

This whole setup is made pretty simple by Erik Sjodin's as3Glue library:

as3Glue is an ActionScript 3 library that enables communication between Flash/Flex/AIR applications and Arduino boards. It can together with one or several Arduino boards be used to monitor sensors (such as rotary encoders and motion detectors), control actuators (such as LEDs and motors) and interface other electronics (such as RFID readers) from Flash, Flex and AIR applications.

The library includes Arduino sketches and ActionScript 3 code examples as well as custom version of the Standard Firmata Arduino firmware and a serial proxy.

The AS3 portion of the library is released under the MIT license, and provides methods for setting pin modes and writing digital and analog data to pin output. It also provides event callbacks for receiving digital and analog data back from the device. The only wonky thing is that the proxy doesn't appear to be released in source form (as far as I can tell), and it's only provided as binaries for Windows and Mac users. On the bright side, it's pretty easy to digest what's happening from the Arduino.as file and the Standard Firmata protocol, so it wouldn't be a huge ordeal to cobble together your own proxy if you know a little C or PERL.

as3Glue - Arduino control from Flash, Flex and AIR
SimpleIO.as - a decent AS3 Arduino example
Firmata - host machine to microcontroller communication protocol

After yesterday's fish blimp piqued my interest in quiet flying robots, I stumbled across this teleoperated blimp with a stereo vision system. Called YARB (Yet Another Robotic Blimp), the blimp is controlled remotely from another computer via a wireless connection and onboard firmware.

The project is made by Surveyor, the company that created and sells an open-hardware, free-software stereo vision system, which basically bundles the two cameras, a wireless connection, servo controllers, and a uclinux-based embedded server all into a single package.

The device looks to be just what you'd want in an out-of-box airborne telepresence system, but it'll set you back about $550. For comparison, and in case you've ever wondered, it takes about 840 kw hours or approximately $50 worth of electricity to produce enough hydrogen to lift your own butt off the ground. While this may not put things in perspective, it sure is an awesomely random fact that you can unleash next time you find yourself talking about blimps in a party conversation.

YARB (Yet Another Robotic Blimp)
Surveyor Stereo Vision System

There's not a whole lot of information yet on this Fin-Fish blimp that was entered by team LaChLuVe into a recent airship regatta in Friedrichshafen, Germany. It suffices to say that it's one of the more unique and beautiful R/C blimps made to date, both from an aesthetic and a technical, propulsion design standpoint.

From the looks of the video, the servo actuated pectoral fins are used as control surfaces to both steer and control elevation. The tail serves dual purpose as well, providing propulsion and acting as a rudder during hard turns. I know it's how fish have been rocking things since the Paleozoic, but I'm still surprised to see how effectively this design functions in a man-made craft.

Fin-Fish by LaChLuVe, Empa Dübendorf, Switzerland

Maurice Ribble of Massachusetts created a high-speed photography setup which uses the Arduino along with a laser or sound sensor to trigger a camera flash at exactly the right moment.

There are a lot of places on the web that describe how to trigger a flash with an electrical circuit, but I feel that using a microcontroller like Arduino offers big benefits. For instance you can easily add new sensors, or even run multiple sensors at once. Since the triggering of the flash is done in software it's easy to add delays, or make a more complicated triggering algorithm based on multiple sensors. Lastly while the microcontroller does add some cost, it's not much because boards like Arduino can be bought for around $35 and some of this cost for the microcontroller is offset by simpler circuits.

By triggering the flash instead of the camera shutter, Maurice is able to capture events that occur in significantly less time than the approximately 20ms it takes between triggering the shutter and when it actually moves and exposes the film. To do this, he takes the photos in a dark room, sets the exposure time on the camera to 10 seconds, and then uses the auto-triggered flash to time the exposure.

His tutorial contains schematics for the laser and sound sensors, as well as the Arduino source code. Very cool stuff.

Triggering a Camera's Flash with Sound and Light [via hacknmod]
Super Simple Camera Flash Trigger

One of the developers behind the Yahoo Purple Pedals project posted a lot of details about how they went about developing a networked bike that automatically uploads geocoded photos to Flickr.

The team created background applications for the GPS-enabled Nokia N95. The software forces the camera to take photos regularly without user interaction and posts the photo, the device's IMEI ID and the current location to a server application over HTTP. Finally, the server application matches the IMEI to a Flickr ID in its database and posts the photo to Flickr for the world to see.

Both the device-side and server-side applications have been made available under the LGPL license, which should give you a pretty significant head start with developing your own mobile-photo project.

Coding a Networked Bike
Purple Pedals

If the Beagle Board caught your eye, here's another embedded Linux platform that's worth taking a peek at. The Linuxstamp is an ARM powered, ultra-tiny, open hardware Linux system that has a bunch of low-power goodies packed into what appears to be a 3 inch by 4.5 inch footprint.

Compared the the Beagle Board, the Linuxstamp has a bit less processor muscle and lacks video output. To its advantage, it has on-board 10/100 Ethernet, and (I presume) it has lower power requirements, making it a better fit for some embedded needs. Both projects are near the same price point (Linuxstamp: $120, Beagle Board: $150), so you'll be able to make decisions mostly on feature-set when choosing the platform for your next project.

Linuxstamp Project Wiki at Open Circuits [via ladyada]
The Linuxstamp Store

Jimmie P. Rodgers brought a whole bunch of color changing LED throwies to Providence recently, and I just had to get some of the LEDs he used for my own enjoyment.

Each piece has three LEDs inside that are under the control of an embedded microcontroller. There are two main variants: fast flashing, and slow flashing. The slow flashing models have more of a gradual change to them as shown in the video above. You can also get diffused and clear versions of either. Unlike the four-lead common cathode or anode RGB LEDs, there is no way to control the mix of colors (you just have to sit back and enjoy them).

The best place I've found to buy these is eBay, where Jimmie and I have both found them for around 25 cents each (shipped) to the USA. A search for rgb led slow or rgb led fast should turn up some.

It may take a couple weeks for them to arrive, but they are well worth it; use them to make some LED throwies, and let the fun begin.

Raphael Abrams just posted a peek inside his portable hacking lab to the NYC Resistor blog :

I like to hack on the go. So I made a charming little mini lab out of a cigar box and some electronic parts. It's got a breadboard, a built-in Arduino, a couple of places to put loose parts and a control panel on one side. The control panel is the best part with LEDs, potentiometers, a switch and a button all mounted on the side of the box. I love it so!

Hand made since 2008, Raphael Abrams' Cigar Box Lab

Berto Aussems wrote in again with another modification to the Zoom H2 recorder:

Listening to soundrecordings made in the 360 degree surround pattern mode of the Zoom H2, I found out that the directional sensitivity is bad. Even the stereo recording sounds mono. The front/back channel separation is the same story. So I had to turn the microphones in 4 times 90 degree. With 2 crossed disk's on top of the H2, the directional resolution is now much better. Maybe there are other ways to get better results; this is one. I hope to have some discussion with other H2 owners about this theme.

I'm not sure how much further you can push the recording quality of this little field recorder, but it's promising to see the results of warrantee voiding efforts like these.

Zoom H2 Microphone's Modification

Previously:
Zoom H2 line input hack - make a 4 channel field recorder

Matthew Karas sent us a hack for creating an iGoogle homepage interface for physical measurement devices. Using an Arduino and a python script, he found a clever way to send real-time sensor data to a Google Gadget, and it doesn't even require having a web server.

I managed to hack up an arduino to upload data to google docs in real time. I then created a real time data gadget and sent that to google home page. That way I can monitor a sensor network from anywhere, with minimal cash outlay. I don't need to have a web host. I did it in two evenings.

The python code can run on a laptop connected the the Arduino. This script reads sensor data from the device and then posts it to a Google Spreadsheet using the python gdata API. From there, you can easily use the spreadsheet as a datasource for a Google Gadget which is then embedded in iGoogle or wherever you want to view your sensor data.

He's posted the necessary code and instructions for making this work. You should be able to customize it for your own projects and get something like this up and running in no time flat.

Real Time Arduino Data To iGoogle Homepage
gdata - Google Data Python API

Trive wrote in about the robochild of a quite unorthodox LEGO/Arduino marriage:

It's a self-balacing robot inspired to the well-known Segway. Its brain is Arduino and that's why it's called "Arduway". Arduino is mounted on a hand-soldered board which connects it to two LEGO NXT motors and an Epson gyroscope.

Aduino Poet, the robot's creator and a student at the Politecnico of Milan, started a library called Arduino2Lego which aims to provide a simple API for the Arduino to talk to standard NXT sensors and motors. Currently, it looks like it only has an interface for motor control, but the project is open source and with any luck, others will chip in and add more features.

Arduino2Lego
Arduway discussion at arduino.cc

Jon Bennett created a nifty wireless telepresence bot out of a thrift store RC car, a Linksys WRT54GL router running the Open-WRT Linux firmware, a network camera, and a microcontroller. He's built two variations: one controlled by a PIC microprocessor, and the other controlled by an Arduino. You can use whichever processor you are more comfortable with, and make one of your own for very little cost using this guide.

The goal of this article is to give a high-level overview of the project and provide some implementation details of the software and electronics. It is not meant to be a step-by-step how-to guide, but there should be enough information for someone with motivation and some background knowledge in electronics and software to be able to make their own Wifi Robot. All of the source code is being released under the terms of the GNU GPL v2, so by all means, use the code, and improve it!

This is one of those basic projects that you can take in a number of directions. Jon's guide will get you through interfacing with your typical RC car electronics and controlling it remotely. From here, it's all software. Someone should take a stab at adding an image processing routine on the remote end to create an autonomous sidewalk cruiser.

Wifi Robot

Our friend Becky Stern posted a video on Craft today which shows you how to mold and cast small parts out of resin. It's something anyone can do, and the process will allow you to make reproductions of small parts, something that could come in handy when you're prototyping (or designing tiny custom army men).

Casting Resin Rings

Standford's Stanford's School of Engineering has released a number of Computer Science and Electrical Engineering courses online, in their entirety, called Standford Engineering Everywhere. The online program includes all course materials—notes, tests, and complete lecture recordings—free for students or educators to use under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.

SEE users may pick and choose the materials that best meet their needs and interests. Want a refresher course on a particular programming concept? View a video lecture that covers the basics. Are you a programming novice? Spend several weeks viewing lectures, reading course materials and tackling class assignments. Test your knowledge by taking quizzes and exams.

As an example, here's the first lecture in the Machine Learning course, taught by Professor Andrew Ng:

The ten courses that are available cover a healthy range of topics. It's basically 3 or 4 semesters worth of EE and Comp Sci. education that you can brainload for free. Here's the current selection:

Introduction to Computer Science

• Programming Methodology
• Programming Abstractions
• Programming Paradigms

Artificial Intelligence

• Introduction to Robotics
• Natural Language Processing
• Machine Learning

Linear Systems and Optimization

• The Fourier Transform and its Applications
• Introduction to Linear Dynamical Systems
• Convex Optimization I
• Convex Optimization II

If you've ever wanted to go to Standford, but didn't have the time, money, or grades, here's your chance.

Stanford Engineering Everywhere [via Creative Commons]

Previously
Lecturefox: free university lectures
Bootstrap Education

Berto Aussems wrote in from the Netherlends to tell us about his hack which replaces the microphones in the Zoom H2 recorder with 4 line inputs, perfect for 4 channel field recording. The Zoom H2 has gotten a lot of glowing reviews in its standard form, but converting it for line input gives you the flexibility to use external mics and direct input sources for a higher quality recording.

The Zoom H2 is a popular portable soundrecorder. It records HQ audio on the 4 build-in microphones on 4 tracks. This hack makes it possible to switch over to 4 self made line inputs on the back of the device. With a few electronic parts for about 10 USD people can make a 4 channel fieldrecorder.

This 3 minute instruction video shows the way you can make yourself a 4 track field recorder. I don't say its easy....but it can be done in an evening. Now I can record 4 channels from my computer audio interface when the softsynth is running.

This is a pretty affordable modification and the device itself is just short of $200. It might be just the solution for a decent 4 track recorder on a budget, whether you're recording your garage band, environmental sounds, or interviews.

Zoom H2 modification; now with 4 line inputs!

Alessio Sangalli has been maintaining a guide for a few years that shows you how to create a serial port IR receiver from scratch and use it in both Windows and Linux. Her design is pretty slick since, as you can see from her photo above, the whole package fits neatly inside a standard 9 pin serial connector. There are still plenty of machines that don't have built-in IR support, so this could be handy if you're thinking of turning an old box into a media player or DVR.

How To Build A Simple But Cool IR (Infra Red) Receiver

Gene Hacker created a 3D printer out of LEGO. It's like a lo-rez reprap that operates in polar coordinates instead of the more familiar cartesian system. This is still very alpha and his demos show some promising 3D blobs of frosting. With that in mind, however, most of the basic functionality of a rapid fabrication system is here. Hacker posted the necessaries to Instructables, so you should be able to replicate his design and put your mind to making it even better.

Build a Polar 3-D Printer from Legos [via BoingBoing]

"Ron" Tajima's Wii Balance Board Roomba looks like a fun way to clean the carpet. The idea is that you surf on the Balance Board, leaning forward or back to steer the robot. The video is a little short on details, but he's using a laptop to read the bluetooth data from the Balance Board and then send control signals to the Roomba bluetooth adapter.

You might recognize Ron from some other Roomba hacks he's done. A while back, he showed how to control the Roomba with the Wiimote (similar to the balance board hack), but the real gem of his collection is Rommba PacMan:

"Ron" Tajima's video channel [via Balance Board Blog]

Hackszine pal Patti Schiendelman tipped me off to the Beagle Board, a spartan little embedded platform, perfect for all things hackable. It's based on the TI OMAP3 processor, which is packaged with 128MB of DDR RAM and 256MB of NAND Flash all on the single chip in the center of the board.

Instead of including things like ethernet and 802.11 on-board, they opted to keep the footprint small and only include the bare essentials: DVI for monitor output, SD/MMC for storage, audio in/out, and USB for device expansion. If you need any other hardware, just get a USB device that has a Linux driver.

Did I mention it's $150 and draws less that 2 Watts? This is definitely what you need for your next autonomous spy weather blimp.

BeagleBoard.org
BeagleBoard Embedded Linux Wiki
Linux Journal - The BeagleBoard: $149 Linux System

We posted David Cranor's Arduino card reader the other day, and today he wrote in with an even better magstripe hack: a way to simulate a card swipe using an iPod an electromagnet. David writes:

When the card is swiped past the card reader, the changing magnetic field of the passing flux reversals induce a current in the reader element, which is then decoded into binary bits, and the original data stored on the magnetic stripe is reconstructed.

So, in order to emulate a particular magnetic stripe, all we need to do is find a way to recreate the pattern of the way its magnetic field changes as it's being swiped past the reader. How are we going to do this? With an electromagnet!

...

The final piece of this puzzle is how to control the electromagnet. Well, we're trying to recreate a particular waveform of current through the solenoid in order to create a particular waveform of magnetism. What's a common way of storing waveforms and converting them to electric current? Sound files! So, all we have to do is encode the highs and lows representing the desired flux reversal pattern into a .wav file and play it back on an iPod or similar music player through the solenoid.

So between these two howtos, you now know how to read the contents of a magstripe card, encode that data into a wav file, and then simulate a card swipe using that recorded data. For more information on magnetic stripe technology, you should check out "A Day in the Life of a Flux Reversal" by Count Zero, written in 1992 for Phrack #37.

It'd be cool to make a nice looking version of the interface so that you could put all your cards, be they student IDs, bank cards, or gift cards, on your iPhone. My guess, though, is that there's no chance any supermarket checkout attendant would let that simulated card slide. On the bright side, this aught to be a reminder that a thing you have (magstripe card) isn't very sufficient as an identification tool unless it's combined with a thing you know (pin number) or a thing you are (a face that matches the photo on the card).

Magnetic Stripe Card Spoofer
A Day in the Life of a Flux Reversal - Phrack #37

Previously: Decoding magstrip cards with Arduino

Instructables user powerpants created a quick and dirty card reader interface with an Arduino. The Arduino decodes the data from the swiped card and transfers it to a PC over a USB serial connection.

This instructable shows how to use some freely available code, an arduino, and a standard magnetic stripe reader to scan and display the data stored on magnetic stripe cards such as credit cards, student IDs, etc.

I was inspired to post this after reading the intro to magnetic stripe reading and Stripe Snoop that is found in MAKE magazine Volume 1. That tutorial details how to interface a stripe reader to a game port interface, but I have a mac laptop, so I don't have a game port interface!

There are a lot of cool uses for this besides just seeing what kind of personal information is contained on all the cards in your wallet (you'd be surprised). A friend of mine in college once hacked together something like this with Microsoft Word and a bunch of Visual Basic macros to automate computer literacy testing for the whole campus. Students could swipe their student id, the test would start automatically, and when they were finished the results were saved to a database. He was hired to administer all these tests manually, so he basically put himself out of a job after a month and got a promotion.

Arduino Magnetic Stripe Decoder
Magnetic Stripe Reader from MAKE: 01
Stripe Snoop - magstripe research tools

Dan Guido from the Information Systems and Internet Security Lab at the Polytechnic Institute of NYU wrote in about the Institute's 5th annual Cyber Security Awareness Week. If you're in high-school or a college undergraduate program, this is a great opportunity to test your infosec skills against your peers, and hopefully earn a little prize money in the process.

ISIS Lab is organizing NYU-Poly's 5th annual Cyber Security Awareness Week (CSAW) where students can compete and win prizes in a variety of information security challenges. There will be door prizes, raffles for participating, and bonus prizes for undergrad and high school participants. Qualified finalists will receive a travel scholarship to attend the awards ceremony in New York City.

There are a number of events, including an application security "capture the flag" challenge, a security quiz which covers everything from cryptography to risk management, and a 5-day forensics puzzle. There's even an embedded systems challenge where teams are tasked with trying to find hardware and software bugs in a mock control system.

This looks like a lot of fun. Some of the contest materials become available at the beginning of September, so sign up soon if you're interested in participating.

Cyber Security Awareness Week 2008

MAKE's Collin Cunningham really impressed me with this short film "A Date With Peggy," a story of an overworked hacker finding relaxation through his craft.

After a frustrating day at the office, it feels good to go make something that simply works. (playing with a bunch of ultra-bright LEDs doesn't hurt either)

The Peggy kit from Evil Mad Scientist Laboratories is sort of like a big kid's Light Bright. It's a large 25x25 array that you can wire LEDs into however you like, without worrying about details like load resistors. The LEDs aren't individually addressable, but you do have some programatic control over the whole array, and there's a built in light sensor that you can use to adjust the display based on light conditions.

A Date With Peggy
Peggy kit at the Maker Shed
"Peggy," A Light Emitting Pegboard Display - Evil Mad Scientist

Ladyada and PT have kicked off the first episode of their Citizen Engineer video series in style. This episode explores GSM SIM card technology and the more retro tech found inside a retired Bell payphone. Ladyada shows how to create a SIM reader which you can use to do things like read deleted SMS messages or brute-force the card's secret key. In the second part, the team dismantles an old Bell payphone and hacks it to function as a home telephone, require quarters for use, and make Skype calls.

Citizen Engineer

Check out Daniel Andrade's binary LED clock built using the Arduino. It's well thought out, including controls for setting the time and hibernating with the LEDs off. Each hour and minute digit is represented in binary form, so it's actually fairly easy to read once you get accustomed to it.

The circuit and source are available from Daniel's site. If you're ahead of the game and already thinking about what to do this Saturday afternoon, this might be a fun option to add to the list.

DIY: Binary Clock with Arduino

Desertfoxx sent us a tip to a classic KipKay howto video. It's pretty easy to swap out the diode in a laser pointer or similar laser housing with the diode from an old DVD burner. Put the whole deal into a mini Maglite and you've got yourself a nice little handheld fire starter, perfect for lighting matches or popping dark colored balloons from across the room. Like all lasers, it's also excellent for quickly blinding people, so watch where you point the thing.

If you haven't caught KipKay before, he's been doing some fun weekend project video podcasts for MAKE.

How To Make A Burning Laser Flashlight