Half Keyboard, Half Guitar, Totally Radical, the Tabstrummer!

While tablature-based music probably annoys “properly” trained musicians to no end, it has given many musicians and musical-hobbyists their first introduction to the world of guitar. The [Tabstrummer] takes this to a whole new level, allowing chords to be programmed into this instrument and played back. Once pre-programmed chord is set, the “conductor-strings” are strummed to allow the chord to play.

This device is based around an Atmel microcontroller and features a MIDI output as well as an audio-out jack. Besides the interesting electrical hardware, the housing seems to be quite well-built featuring what appears to be an acrylic or polycarbonate body. Although not quite the same thing, possibly some influence was gained from the [Keytar]. It’s heyday may be past, but not forgotten.

Check out the video below for a Christmas-themed jam played on the [Tabstrummer] or check out their video page for several more songs. This “hack” is being considered as a commercial product, so the inventors would love to hear your feedback! Continue reading “Half Keyboard, Half Guitar, Totally Radical, the Tabstrummer!”

A study in AVR power saving techniques

amtel_avr

[Scott] found the iCufflinks from Adafruit Industries pretty interesting, but he thought that the stated run time of 24 hours was a bit short. He figured he could improve the product’s power consumption at least a little bit, to improve the overall battery life.

From their schematics, he placed an order for parts and built two identical iCufflink mock-ups side by side – one running their code and one running his. He took baseline current draw measurements, then got busy slimming down the cufflinks’ software. It had been 20 years since he touched assembly, and he has never written it for an AVR, but judging by his work he’s not rusty in the least.

He slowed the ATtiny’s clock down and tweaked a few other settings for a savings of 53μA, but the real improvements came via a fairly simple fix. The original code called for the processor to institute a counting loop to sleep, which he found to be very wasteful. Instead, he chose to put the processor in an idle state, using the chip’s watchdog timer to wake it when it was time to pulse the LED. The power savings from this change alone was a whopping 261μA!

When he was said and done, the changes save about 315μA of current draw, and should allow the cufflinks to run for up to 38 hours without swapping batteries. In [Scott’s] opinion, a nearly 60% improvement in battery life is pretty good for a day’s work, and we’re inclined to agree.

Regarding Atmel’s Xmega chips

A few years back Atmel announced a new line of chips, the XMega series. We see the name bouncing around here and there, but when [Michael Kleinigger] mentioned that he’s seen very few project using these chips we realized that not only is he right, but we know next to nothing about them. Just give his XMega review post a whirl and you’ll be up to speed in no time.

He compares an XMega128A1 side-by-side with an ATmega1280. For those that abhor reading paragraphs full of words, there’s a table that can give you the quick facts like how the XMega costs less and runs faster. But we know from past discussions (like the one on PWM) that [Mike] knows his stuff so the whole thing’s worth a read. He’ll lead you through the programming tool chain (which hasn’t changed), a bit about the new event system, and then finish with a demo program on the Xplained development board.

$14 swarm robot, kilobot, is extremely cool

Reader, [Michael Rubenstein], sent in a project he’s been working on. Kilobot, as stated in the paper(pdf), overcomes the big problems with real world swarm robotics simulations; cost, experiment setup time, and maintenance. The robot can be communicated with wirelessly, charged in bulk, and mass programmed in under a minute. Typically, robots used for swarm research cost over a $100, so large scale experiments are left to software simulation. These, however, rarely include the real world physics, sensor error, and other modifying factors that only arise in a physical robot.  Impressively enough, the kilobot comes in far under a hundred and still has many of the features of its costlier brothers. It can sense other robots, report its status, and has full differential steer (achieved, surprisingly, through bristle locomotion). There are a few cool videos of the robot in operation on the project site that are definitely worth a look.

Programming an ATtiny using an Arduino

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[Scott] is a big fan of the Arduino platform, and he’s not afraid to admit it. It does all the things he needs, but now and again he would like to use something a bit smaller, without all the bells and whistles the Arduino has to offer. He contemplated using an ATtiny for smaller projects, but after looking into what he would need to program the chip under Linux, he could never find the motivation to give it a go.

That all changed when he discovered the Arduino-Tiny project, which aims to bring a limited Arduino IDE to the ATtiny line of microcontrollers. He found the project to be quite useful, so he put together a brief tutorial that walks through everything you need to get started.

The tutorial is fairly straightforward, and even demonstrates how the Arduino can be used as an ISP for the ATtiny, removing the need to purchase a standalone programmer. Be sure to check it out if you are searching for an easy way to get started with ATtiny chips under Linux.

Small POV device shows off some big features

We’ve already added the components needed to build [Rucalgary's] tiny POV device to our next parts order. The little device sets a new standard for tiny persistence of vision boards. Instead of relying on the user to find the best speed and timing for swinging the board around, [Rucalgary] used an accelerometer. This is the point at which we’d usually groan because of the cost of accelerometers. We’re still groaning but this time it’s for a different reason.

The accelerometer used here is a Freescale MMA7660. It’s an i2c device at a super low cost of less than $1.50. The reason we’re still groaning is that it comes in a DFN-10 package that is a bit harder to solder than SOIC, but if you’ve got patience and a good iron it can be done. An ATmega48 drives the device, with 8 LEDs and one button for input. On the back of the board there’s a holder for a CR2032 coin cell battery and a female SIL pin header for programming the device.

Check out the video demonstration embedded after the break. We love it that the message spells and aligns correct no matter which way the little board is waved.

Continue reading “Small POV device shows off some big features”

Blackberry LCD reverse engineering

blackberry_lcd

[Scott] was looking to source some LCD screens for an upcoming project, and was considering buying them from SparkFun. While the Nokia panels they sell are not expensive, they aren’t necessarily the cheapest option either – especially when building in volume.

He searched around for something he could use instead, and settled on Blackberry screens. Old Blackberry models were even more durable than the current offerings, plus companies are trying to get rid of old handsets by the truckload. The only problem was that he could not find any information online that would show him how to write to the screens.

It took a bit of digging, but he eventually determined which ICs were used to drive the LCD screen. He had no luck finding screen pinout information online, so after spending a few hours testing things with his multimeter, he came up with a full listing on his own.

He wired up a connector so that he could use the screen on a breadboard, then got busy writing code to display some text on the screen. Everything came together nicely as you can see in the video below, and he has released his code in case anyone else is looking to repurpose some old Blackberry screens.

All we want to know is what sort of project all these screens are going to be used in.

Continue reading “Blackberry LCD reverse engineering”