[Satiagraha] let us know that Texas Instruments(TI) has given out a neat “LED Reference Design Cookbook” PDF. The document contains 17 some odd little projects featuring different TI ICs and ways of using them to control LEDs in things from backlights to torches to solar lanterns to advanced PWM control! Sure the document is biased towards using TI equipment, but that shouldn’t stop you from recreating, modifying, and generally just having fun with their designs in your own productions.

mbed is a next-generation 32-bit microcontroller platform. It’s a prototyping and teaching tool somewhat along the lines of Arduino. On steroids. With claws and fangs. Other contenders in this class include the MAKE Controller, STM32 Primer and Primer 2, Freescale Tower, and Microchip’s PIC32 Starter Kit. The mbed hardware has a number of advantages (and a few disadvantages) compared to these other platforms, but what really sets it apart is the development environment: the entire system — editor, compiler, libraries and reference materials — are completely web-based. There is no software to install or maintain on the host system.

The Hardware

The mbed board is sensibly priced at $60; about middle of the road among its peers. mbed’s size (or lack thereof) is among its greatest assets, measuring only about 1″ by 2″ (26 x 52mm) in a stout 40-pin DIP package that just barely manages to fit in a breadboard…a major win.

The top of the board is dominated by the microcontroller itself: a 60MHz NXP LPC1768 based on the eminently capable 32-bit ARM Cortex-M3 core, sporting 64K of RAM and 512K flash, and rounded out with an embarrassment of peripheral riches: Ethernet, USB (host, device, and to-go), CAN bus, multiple serial, I2C and SPI buses, 12-bit A/D and even a 10-bit D/A converter and realtime clock/calendar. Also on top is the USB connector (mini-B), some power regulation circuitry (operating on 4.5 to 9 volts DC, or USB power), several indicator LEDs, and the reset button (a plain vanilla tactile switch on our purchased unit, not the candy-like blue button seen in product shots).

The underside conceals an Ethernet transceiver chip (requiring only the addition of an RJ45 jack to get the board on a network) and a DiskOnChip-style component that provides a small (about 2MB) FAT filesystem when attached to a host system through USB, much like a thumb drive.

This latter feature — the FAT filesystem — is half of the key to mbed’s software-free, cross-platform magic. Getting new code onto the device is simply a matter of copying the compiled program (as a .bin file) to this drive. Press the reset button, and the new code is copied to the MCU’s internal flash and run. No special programming hardware dongle, no special bootloader software, just drag and drop. This has some serious implications. Pretty much any system these days can mount a FAT filesystem. We’re not just talking about getting Mac and Linux users into the fold alongside Windows…there’s also the impending wave of featherweight netbooks with ARM and VIA chips running peculiar, instant-on operating systems. Or the OLPC XO-1. Or older PowerPC Macs. The computers in the school’s lab that you’re not allowed to install any software on. Game consoles.

The Software

“Cloud computing” is still the hot buzzword this week, and the mbed project has adopted the concept wholeheartedly, comprising the other half of their softwareless strategy. Everything with mbed — everything, even your own source code — resides on their servers and is accessed through a web browser. This carries with it all of the good and bad points of any other network-based service such as Google Docs. There’s the potential for this to be a fantastic tool for teaching and collaboration, and in fact they’ve created such an online community for mbed, with forums and publicly-shareable code libraries. One can move between home and office, or travel around the world, and resume editing code on any system with a solid ’net connection. No need to check for software updates; the server will always be current.

mbed programs are written in C++ (yes, thankfully it’s “programs” and “C++,” not “sketches” or “the mbed language”) using their JavaScript-based online editor. When ready, click the Compile button. The compiler and linker run on the back end, on the server at the other end of the network connection. Provided your code is all syntactically valid, a compiled .bin file will then be downloaded to your computer…save this to the mbed USB disk, press the reset button, and you’re good to go. In Arduino-like fashion, the mbed device also appears as a virtual COM port, so you can monitor a program’s serial output using any terminal program.

The Good

We were taught that you should always say something kind before criticizing, so we’ll point out that the above process does, in fact, work exceedingly well, and has proved to be both quick and reliable. Once you get into the groove, the sequence of operations is no more onerous than with Arduino or any other microcontroller-specific programmer dongle.

To their credit, unlike some microcontroller evaluation kits, there are no artificial limitations to the mbed compiler; the full code and memory space of the processor is available to your code. The editor has realtime syntax coloring and multiple undo levels. And double-clicking on an error message in the compiler output will take you directly to the offending line, as in any decent IDE. You can import existing code from your local system to the mbed “cloud,” or likewise export individual files or an entire project. All good stuff.

The real saving grace of this setup is the libraries, both the official functions in what they call the “Handbook,” and community-contributed code in the “Cookbook.” A tremendous amount of functionality has been implemented in a concise and usually object-oriented manner. It’s almost comical sometimes, after having worked with other microcontrollers and girding for some expected coding nightmare, only to find that the corresponding library handles a task in a couple of lines (browse through the Handbook and Cookbook for examples). There’s a tendency also to follow stdlib or “UNIX-like” conventions for file access, character I/O, realtime clock access, etc., so existing systems programmers new to microcontrollers will feel right at home, no weird function names or syntaxes.

The mbed’s FAT filesystem is also accessible to the microcontroller, making it useful for more than just program storage. Web pages can be served from this space, or a data logging program can store results here. If the two megabyte capacity is too limiting for your needs, have a look at the SDCard library in the Cookbook — it’s almost trivial to wire up and use. Pretty much all of the libraries are like that!

The Bad and the Ugly

Hardware-wise, there are just a few minor nitpicks:

First is with the local FAT filesystem. Even though this is one of the device’s most unique features, and the very thing that enables its platform neutrality, the implementation just seems a bit anachronistic. The aforementioned SDCard library demonstrates how readily that format can be used. It’s faster, with the potential for far greater capacity, and cards could be easily swapped out for different code or data files. Not a major disappointment, just seems like an opportunity was missed to make this product even better.

Second is with the indicator LEDs on the board. Four of them, scant millimeters apart, all blue…making them pretty much worthless as status indicators from across the room, where they all blur into a singular blob. Ten years ago, blue LEDs were novel. Five years ago, they were mainstream, festooning every last USB hub, mouse, flash drive and imported piece of crap. Today they’re just tired, let’s get over it. Different colors would indicate status at a distant glance.

Finally, not a problem with the mbed board itself, but it would be nice to see one of the Cookbook projects, the “BoB2” breakout board, made into an available product. The blank board can be ordered through BatchPCB, but after postage and handling the price for just the empty board — no components — is $33. Have this populated and mass-produced, bundle it with the mbed in a $100 package, and it sounds like a winning setup, ready to go head-to-head with the MAKE Controller.

But really, those are just nitpicks. Our real beef is with the software…the code editor specifically. If you find the Arduino editor aggravating, the mbed editor will have you seeing red (or maybe purple if you factor in all those blue LEDs). Like Arduino, there’s no true tab formatting; everything’s expanded to spaces, like it or not. Auto-indent cannot be disabled, and there’s seemingly no command to increase or decrease the indentation of a block of code. If you’re accustomed to anything more than arrow keys to move and click-and-drag to highlight text, the editor disregards a lot of system-native editing behaviors that may be deeply ingrained in your muscle memory (such as shift-clicking to select a range of text, or triple-click-and-drag for multiple contiguous lines). What’s more, the quirky behaviors are a little different across each browser and operating system. Don’t even try that triple-click-and-drag in Firefox for Mac…you won’t get your text cursor back without a complete reboot (seriously, just restarting the browser isn’t sufficient). And at present, only the most common browsers are supported; all others are currently shut out.

The closed-source nature of the tools may also be off-putting to some. If one finds the Arduino editor distasteful, there are options: get in there and change the code, or simply use a different editor and link with the Arduino libraries manually…it’s all legal and encouraged. With mbed, there are no alternatives. Access to the compiler and libraries is “free as in beer,” but not “free as in speech.” There’s little recourse should the service ever be taken down, or if they should suddenly start charging a subscription fee (there’s no indication this is planned, just a hypothetical scenario).

The good news, at least with regard to the former, is that software is of course infinitely more malleable than hardware, and it’s almost certain the tools will improve with time. The site is under active development…new “Home” and “Notebook” features were added for registered users just yesterday. Perhaps, given time, they’ll get the Command key working properly on the Mac. The selection of user-submitted code will expand regardless, making it progressively easier to do more and different things with this board.

In Summary

The mbed Tour page is frank about what the platform is good for, and what it’s not. mbed was intended as a quick prototyping and educational tool, and at that it excels. A lack of features such as a debugger or offline compiler keep this from being a professional-strength development platform, which is okay. Think of it as Arduino: The Next Generation. Although the mbed board costs more up front than Arduino, there are capabilities here that would otherwise require costly “shields” and strain every last byte and CPU cycle of the 8-bit ATmega328 processor: Ethernet, USB, SD cards…mbed handles these tasks with aplomb.

mbed is not without its flaws, and the “cloud” development approach may never sit right with some. For a product that’s just weeks out of beta testing, the results thus far are extremely encouraging. There’s immense potential here: a seriously powerful chip, easy to interface and to program. If the online tools can be improved, or if open source alternatives become available, mbed could be a major player. We expect to be seeing a lot more of this device in future hacks.

[Ania] wrote in to let us know her team had finished the Multixylophoniomnibus and that they have posted an extensive writeup about it. We covered this augmented xylophone when it was still in development at the beginning of this month. Originally they wanted to use mallets wrapped in tinfoil as switches that close when they contact the metal keys, something akin to matchbox cars as a switch. This plan was thwarted when they realized the paint surface insulated the metal keys. At this point they switched to piezo sensors which turned into an odyssey of trial and error to achieve a reliable input for the Arduino to monitor. In the end they got it working with around forty lines of code, interfacing six boxes containing a different type of noisemaker.

See the finished instrument played in the video after the break. Alas, the addition of the piezo sensors do impede the resonance of the xylophone keys, but we still like it! There’s something reminiscent of the beginning of Pink Floyd’s Money when this is played.

[Gio] enjoys using vacuum tubes in his projects. He designs the circuits using a CAD program but was finding that there is no substitute for actually building a prototype before heading to a final design. To make this process easier, he built his own tube prototyping station.

At the top of the board he’s got three different sizes of tube sockets with the pins from each wired as common. The nine pins from the sockets break out to a terminal strip where they can be interfaced with a solderless breadboard. For added versatility he’s included terminals to tap into some RCA jacks, as well as a 100 kOhm variable resistor. We’d bet this is not something that you can find ready-made, but it sure does look a whole lot better than a workbench full of components alligator-clipped together.

How often do you change the batteries in your television remote control?  Yeah, basically never. But that’s a tribute to how efficient the device is and not a reason to overlook this development. NEC is showing off a remote control that uses no batteries. Power is generated using the piezo effect that occurs when a button is pushed. That is to say, when a crystal is compressed it emits a tiny bit of electricity which is harnessed and used to power this device. This is the same principle that is used in the electricity producing sidewalks tested in Japan.

It’s pretty phenomenal that they can run the device using this method. Right now there’s only a handful of buttons but we’re sure there’ll be advances in the technology. There’s a ton of use for this if it can be miniaturized. It is using radio frequency instead of infrared, making it a useful development in wireless doorbells, garage door openers, key-less entry fobs for your car, and many more applications.

[Thanks das_coach]

As you can see above, there is no wiimote in that accessory steering wheel. There is, instead, a home-made accelerometer controller that connects to the pc via USB. Based around a PIC 18F2550 and a 2 axis accelerometer, this device is detected by windows as a standard controller. The schematic and source code are available on his website. He says it can also be used as a “motion mouse”. You can see a video of that after the break.

When we first saw the video, we thought it might be the same person as the accelerometer controlled maze project, due to the wiimote steering wheel casing.

[via make]

[Maurice] let us know that his latest photography tool for hackers, the Camera Axe 3.0, is now available. The original allowed you to trigger a high-speed flash and camera from a multitude of sensors, including light and sound. The new one does all that, but also: allows multiple cameras or multiple flashes, clean up of software to make it more user adaptable, and the best (arguably the most important) part – cheaper components! All that and more under the Creative Commons that we do love so much. Keep up the amazingly detailed and just pure awesome work [Maurice].

This neat accelerometer controlled marble maze adds a level of fun to retrieving a gum ball. You have to first navigate the maze using a controller that has a dual axis accelerometer in it to control the angle of the platform. Though that does look like a wii accessory, there is no wiimote in there.  Only after you have completed it will the gum ball machine dispense the candy. [Dan] constructed everything himself, which might explain the lack of “pits” for the marble to fall into in the maze.

More details on the build and source code are available on his page.

[via hacked gadgets]

[Shingo] shared his implementation of a stationary bike as a virtual reality interface. This is similar to the Google Street View setup we covered a week ago but goes a few steps further. They patched into the bike computer to pick up rotation of the bicycle wheel and added an accelerometer for directional control. This setup can navigate through Street View but the video after the break also details an interface with Google Earth and even the ability to navigate through Second Life, following your avatar as it bikes along with you. The use of a wearable display is far superior to something like the SurfShelf and really gives you a goal other than just some cold-weather exercise. So take this idea, patch it into a wearable computer and you’ve got the exercise setup worthy of the future world we’ve been promised.

[Jack] wrote in to let us know about a project that creates a virtual microprocessor core based on the ATmega103 by using a Field-Programmable Gate Array. Great, we thought. Here’s another rather esoteric project like the NES on a FPGA, but what’s the motivation behind it? We asked [Jack] and he provided several scenarios where this is quite useful.

Implementing the AVR core allows code already written for the chips to be easily ported to an FPGA without a code rewrite. This way, if your needs outpaced the capabilities of the microcontroller long after the project has started, you can keep the code and move forward from that point with the added capabilities of the gate array. Having the core already implemented, you then only need to work with HDL for the parts of the project the AVR was unable to handle. He also makes the point that having an open source AVR core implementation provides a great tool for people already familiar with AVR to study when learning VHDL.

With products like the Butterfly that this project is based around, or the Maple we’ve seen in the past, programmable logic for the recreational hacker is starting to get a little easier.

[Chris] wanted a guitar with a keyboard but didn’t want a keytar. Like any good hacker he took a cheap guitar and a small keyboard and introduced them to each other. He moved the control knobs to make room for the keyboard and added the control circuitry from the keyboard to the top of the guitar’s body. A 9v battery is used to power the keys and something called “Chris Collins’ transformer trick” is used to amplify its sound. If you know details on this transformer, leave a comment and we’ll update the post. Take a look at the video after the break to see [Chris] perform the Final Countdown on keys and guitar.

The guitar is a Chinese made Telecaster clone and we think he’s the first one to find a realistic use for keyboards that don’t use full-sized keys. [Chris] apologizes for the lack of build photos but we give him a pass; he lost his phone while crowd-surfing and that’s as good an excuse as any for losing some pictures. We can’t wait to see another performance with this gnarly axe once he’s had enough practice to pull everything together!

[David Cranor] has managed to fit a fully working Uzebox system into an old NES controller. Uzebox, an open source gaming platform based on the ATmega 644 and an AD725 NTSC encoder, is one of a couple systems that are becoming more and more widespread and accessible. There are a number of ready-to-go Uzebox kits available, but for the more hands-on types, [David] has been very generous with his schematics and step by step instructions. These schematics can all be readily reshaped, and would easily fit into controllers with less fun applications and sentimental value.

Today we stumbled upon [jimthree's] Seismic Reflector while looking at projects that employ the Processing language we mentioned a few days ago. Utilizing a Boarduino and some vibration motors from a game controller, the Seismic Reflector does just as its name implies – rattles itself around whenever there is an earthquake. While this does seem a bit silly at first, we were fascinated to learn there have been 165 earthquakes just in the past week and almost no news reports, suddenly this device got a lot more interesting!

While Outerspace may not have an extremely useful function, being an art installation, we really enjoyed reading through the build information. Basically, Outerspace is supposed to appear to be curious, exploring it’s surroundings and reacting to your contact. We do enjoy a little bit of personality in robots, so this seems like it could be fun.  The head has 5 photo sensors and each piece of the “arm” has capacitive sensors. This allows Outerspace to sense what is going on. The motion itself is controlled by 4 servos in the base pulling cables that run through the body.

The programming seems like it could use a little work to achieve the effect of being “curious”, but we see potential here. You can see a video of it in action here.

[via today and tomorrow]

[Robotkid249] details how to build a wireless power transmission system. This is similar to the commercial applications we have seen in a TED talk as well is in a Sony prototype. Power is fed to a ring made of magnet wire. A smaller loop is attached to the system that you want to power and picked up from the base unit. In this case, he is powering some LEDs but the concept can be tailored for your purposes such as an inductive charging pad. We’d like to see a hack that incorporates the base into a mouse pad (or the desk itself) and the receiver into the body of a wireless mouse. We’ve seen a commercial solution along these lines but we want one that doesn’t require a physical connection for power transfer.

[Thanks Juan]