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! Read the rest of this entry »

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.

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.

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.

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[Mathieu] has bee working to refine the code running on an LED matrix, and added some neat display tricks along the way. He wanted to make the display directly addressable from a computer. The 96×64 bi-color LED display is powered by an Atmel FPSLIC and already used double-buffering. Enabling a PC to write directly to one of the buffers was not too hard, requiring just a bit of optimization to get the timing right. From the look of the video after the break, he nailed it.

The video feed is generated from a webcam stream using Matlab to process each image. Just 50 lines of code captures a frame, sizes it appropriately, converts the result to black and white for edge detection, then finishes the job by compressing image data for transmission to the embedded processor. We’d like to say it’s easier that it sounds but we’re pretty impressed with this work. The display manages about 42 Hz with the current setup.

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[jonh] religiously tracks the miles he rides on his bicycle. When his odometer’s battery started getting low, he wanted a way to run the miles up to where they were before, since replacing the battery resets everything to zero. [jonh] used an Atmel microcontroller to run up the miles on his bike computer so he could pick right back up where he left off. There is definitely a Ferris Bueller’s Day Off joke in here somewhere.

The bike computer itself is designed to plug into a base that connects to a magnet-triggered reed relay. It uses a wheel-mounted magnet to count the number of revolutions made and thus the distance traveled. [jonh] hooked up a simple microcontroller-driven circuit to these connectors to trick the bike computer into thinking it was moving, and moving fast! Since he knew the number of miles he wanted to sandbag onto the odometer, he was able to program it to run up the proper amount of miles and then stop. There’s no source code listing for the project, but this shouldn’t be too hard to reproduce. He provides a pencil-drawn schematic for the connection to the cyclometer from the microcontroller. At the end, there’s also some sage advice for those of you who are interested in building a decent hardware hacking lab on the cheap.

Here at Hackaday, we see microcontroller based projects in all states of completion. Sometimes it makes the most sense to design systems from the ground up, and other times when simplicity or a quick project completion is desired, pre-built system boards are a better choice. We have compiled a list of boards that we commonly see in your submitted projects, split up by price range and with a little detail for reference.

After reading our list, sound off in the comments or on this forum post, and we may include your board in a follow-up guide at a later date. We will also be giving away 10 Hackaday stickers to the most insightful, the most original, and most useful advice given on the forum, so if you haven’t registered yet, now would be a perfect time. Winners of the sticker giveaway will be selected from the forum thread, and the final decision for prizes will be judged by the wit and whim of the Hackaday writing team. More prize details to follow in the thread. Read on for our guide based on past project submissions.

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Most of the dice related hacks we run into have to do with pseudo random number generation, but today we saw something different. This sleek looking jumbo die is actually a prize holding box opened by a secret sequence of rotations. Using an accelerometer and an ATmega 328 with a sub-micro servo to control the locking mechanism. Worried about the batteries going flat and losing your treasure indefinitely? Good news! The batteries are accessable without giving away the secret inside.

It also turns out that this is an update to an earlier project from the same laboratory, so be sure to check that out as well to see where this build came from. Code is available for anyone looking to make their own, as well as a useful parts list.

[via Hacked Gadgets]