Get ready to play some wicked air harp

Who needs a tactile interface when you can wave your hands in the air to make music? Air String makes that possible and surprisingly it does so without the use of a Kinect sensor.

In the image above, you can see that two green marker caps are used as plectra to draw music out of the non-existent strings. Judiciously perched atop that Analysis and Design of Digital Systems with VHDL textbook is a camcorder recording an image of the player. This signal is processed by an FPGA (hence the textbook) in real-time, and shown on the monitor seen to the right. A set of guides are overlaid on the image, so the player knows where to pluck to get the notes she is expecting.

The program is designed to pick up on bright green colors as the inputs. It works like a charm as you can see in the video after the break. The team of Cornell students responsible for the project also mention a few possible improvements like adding a distance sensor (ultrasonic rangefinder?) so that depth can be used for the dynamics of the sound.

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Kindle Fire cover from a Moleskine journal

[Kevin Haw] is the proud owner of a brand new Kindle Fire. But to protect the investment he wanted a nice looking case and decided that DIY was the way to go. He ended up repurposing a Moleskine journal as a table cover.

You can do this one yourself in under an hour. Most of the pages in these journals are sewn in place and [Kevin] started by cutting the strings with a hobby knife. Once removed, he used a utility knife to separate the pages that were glued to the cover; this leaves you in the state seen above.

Obviously this unfinished look just won’t do. [Kevin] used some red duct tape duct tape to cover the unsightly spine. This adds strength, and does the job of cleaning up the area, but we might have also applied felt (or microfiber cloth) to the entire inside area for a bit more finished look. The final part is mounting the tablet which was accomplished with adhesive Velcro strips. These can be removed from the back of the Kindle Fire later on if you decided to use a different enclosure.

Simple PCB vise

This one almost got relegated to a links post, but [Ken's] simple PCB vise (PDF) is just so useful we had to give it a standalone feature. It works so well because he made every design feature count.

For instance, the groove the holds the PCB (almost impossible to see here but look at the diagrams in the PDF linked above) is cut with a dovetail bit, rather than just being a square rabbit. The clamping force is provided by that blue rubber band which simply hooks on a metal shelf peg on each side of the clamping plates. Those plates are machined out of polyethylene and slide nicely along the two nylon rods which keep them aligned. There’s really nothing to break or wear out here, except the rubber band with is easily replaceable. The rubber feet keep it from sliding across the bench as you work.

This is great for soldering, and would go right along with those diy smd parts clamps you made. It’s also a great way to hold onto your prototype boards when you’re working out the firmware.

Crunching the numbers: using solar cells indoors

[Mathieu] was interested in using more solar cells for his everday electronics. He looked around but couldn’t find much information about using pholovoltaic for small indoor devices. We remember hearing some of the same things from [Dave Jones] in one of his EEVblog installments from a few years ago which looked at solar calculators; the only indoor solar gadget we can think of.

The quest for knowledge was on and [Mathieu] decided to build this indoor solar cell test platform. It’s a stable piece of hardware that allows him to run reliable tests in many different conditions. It’s designed to compare two identical cells. One is charging the Lithium cell, the other is driving a load directly. A second battery powers the platform separately from the solar circuits so that it can be used as a data logger. He collects, dumps, and graphs info from his test runs, then discusses his findings. We won’t spoil it, but the results are not great. Mostly you need sunlight to get real results as it’s just so much more powerful than artificial lighting.

Sphere morphing hexabot is a mechanical jellyfish

Once again, we’re wowed over [Zenta]‘s robotic skill. A few months ago, [Zenta] posted a video of his MorpHex hexapod spherebot that left us awed. After a few long months, more bits of MorpHex have made it onto the chassis. [Zenta] says his project isn’t done but it’s still enough to knock our socks off.

Going through the [Zenta] archives, there’s a little more to go on this time around. The MorpHex will be made up of two hemispheres, but only the bottom one will be able to walk. That’s really not that bad because [Zenta] gave the upper panels 1 degree of freedom. Just enough to scare off predators, we’re sure.

The chassis and the legs are amazing little pieces of engineering. Despite all the work [Zenta] has put into his MorpHex, there’s still work to be done. He hasn’t gotten the sphere to roll on command yet. We’ll be sure to post a video of the robot dancing to some lo-fi. Check that out after the jump.

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Muff-Fones sound dirty; well, not literally

Baby, it’s cold outside. But that doesn’t stop [Grissini] from listening to some tunes when not indoors. He added headphones to a pair of ear warmers. We guess you could call them ear muffs, which is where the name comes from. But these are the newer type that wrap around the back of your head.

[Grissini] picked up a set of headphones that similarly wrap around the back of your head. After pulling the speakers out of their plastic enclosures he needed a way to soften the sharp edges when they’ll be pressed against your ears. Sugru once again shows its versatility by providing a soft, self-bonding, and moldable surface. The last step is dead simple, as the ear warmers already have a fabric pocket by each ear perfect for accepting the speakers.

Now we need this to go one step further, by making them wireless. We figure hacking in a bluetooth headset board would make it work with your cellphone. Or you could roll your own minimal MP3 board and house it in the part that wraps around your neck.

GE Color Effects hacking for the nautically inclined


[Jim] wrote in to share some work he did with GE Color Effects LED lights in an effort to create a light display for his boat. He saw our coverage of the Color Effects G-35 hacking efforts by DeepDarc last year, and knew that they would be prefect for the boat. He did some careful scouring of eBay to score 8 strings of lights at bargain basement pricing, then he got down to the business of hacking them.

He originally built a control circuit using a single PIC18F, but just before he started to put everything together, he realized that wiring everything up would be a huge undertaking. Going back to the drawing board, he decided it would be best to replace the lights’ stock board with one of his own. Now, he uses a single master controller board to send messages to his slave “pods”, significantly cutting down the amount of wiring required for the project.

The display looks great as you can see in the video below, though as many do, [Jim] has plenty of improvements in mind for the future.

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