Speaker-mounted WAV player for street performances

This naked speaker is the basis for [MaoMakMaa's] newest project called the Wavedrone. He plans on using the autonomous and cable-less device during street performances. You can hear the effect of some stretched jazz cords being played on it in the video clip after the break. The sound is kind of an ethereal background noise that observers might not immediately realize is there.

You can see the 9V battery which serves as the power source clinging to the frame of the speaker. A 7805 linear regulator tames that battery and feeds the two IC’s on the circuit board seen to the right. The ATtiny85 is reading music from an SD card and playing it back in mono (obviously) with the help of an LM386 audio amplifier chip. The trimpots that go into the high pass and low pass filters in between the microcontroller and amplifier allow for a bit of sound manipulation, but we’re more impressed with the quality of the sound this is getting when properly trimmed.

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Chumby controlled mechanum wheel robot

[Madox] gutted an Insignia Infocast to use with this robot. Insignia is Best Buy’s house brand and they partnered with Chumby to make their Infocast line. If you can find a used or clearance model it’s a great way to get yourself and embedded Linux board for a project like this one.

The body and wheels are 3D printed, with design files available at [Madox's] Thingiverse page. The mechanum wheels work amazingly well, using seven bearings each for smooth operation. The body itself includes a holder for two groups of batteries. One of those battery packs powers the Chumby board while the other is used to power the four servo motors responsible for locomotion. To simplify the electronics [Madox] chose to use a USB servo drive which only set him back about $20.

We’re not sure what the USB dongle on top of the robot is used for. We’d guess it’s a WiFi adapter, since the machine sets up its own access point to act as a controller. But we thought Chumby boards had WiFi built-in. At any rate, check out the video after the break where you can see an Android phone driving the little bugger. There’s a flaw in the code that prevents side-to-side movement, it gets fixed after a video break at about 2:15 and everything is peachy after that.

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[Easton's] animatronic hand gets 3D printed upgrade

[Easton] as been working with [Jeremy Blum] to come up with the newest version of his animatronic hand. You may remember seeing [Easton's] first animatronic hand, with which he won his regional science fair and made a trip to nations. Since then he’s been working on improvements, and with access to [Jeremy's] Makerbot he harnessed the power of open source design to make his own printed hand, extending a different Thingiverse project.

He’s still using the original sensor glove as a controller. It sends commands to the Arduino controlling the arm via an Xbee module. From there, five servos inside a fiberglass forearm move each finger and the thumb. The video clip after the break gives [Easton] a chance to show off all of the new design features, and finishes with a demonstration of the hand grasping different objects. We had a chance to chat with him briefly. He’s got big goals for himself, aiming to design a prosthetic arm for under $1000. That’s not a career goal… he’d like to get it done this year.

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Got an iLight?

[KaRMaN] sent us a piece from his blog on what to do with a busted iPhone (google translate). As many iPhone owners have found out, it does not take that much of a fall to render your shiny hand-held command center into a pile of shattered glass. Replacement parts and insurance are available so life goes on, but what else can you do?

One thing you could do if your screen split apart like [KaRMaN]‘s is remove the white LED back light strip from the device and reuse it. Once he removed the LED he had to repair a couple of traces but that is no big deal. Then the strip is probed to see how the individual LED’s are situated, in this case is 6 in series. The strip is hooked up to a 12v power source and now you have a small, but bright light for some midnight hacking.

Revolights keep you safe while riding at night


Bicycling at night can be a potentially hazardous endeavor for several reasons, but primarily because well, it’s dark. Inattentive drivers, weather, and other factors aside, the most important thing you can do to keep yourself safe is to ensure that you can see and that you are seen by others.

Revolights, an invention put together by [Kent Frankovich, Adam Pettler, and Jim Houk], is an ingenious way of accomplishing both of those things. The ring-shaped system attaches to nearly any bike tire, and includes LEDs that shine like a car’s head and taillights. A magnet attached to the bike’s fork triggers the onboard microcontroller to light only 4 LEDs at a time, letting persistence of vision take care of the rest.

We think it’s a great idea, and clearly others do as well. With nearly a month left on their Kickstarter page, they have nearly doubled their initial funding goal.

Check out the video presentation on their Kickstarter page to get a better look at the Revolights project.

[Thanks, medix]

Mineable Minecraft block

At Hack A Day, we’re pretty big Minecraft fans so you can imagine our interest when we saw [Ben Purdy]‘s real-life Minecraft block. The build uses a projector system to display a block onto a cardboard box and reacts to being ‘mined’ just like in the game.

Block animation is handled by a piezo sensor, an Arduino and a Processing sketch. From earlier posts on [Ben's] blog, we’re going to guess that he used the keystone video projection library his own solution to map the Minecraft block onto the cardboard box. Animation is handled just as in Minecraft – overlaying the breaking animation onto the block and adding some particle effects.

We’ve seen a few Minecraft hacks before, like using it as a 3D design tool, and connecting your redstone CPU to the outside world. [Ben]‘s build follows in the tradition of its forebears and is something we really want to try out. Check out the demos after the break.

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A cat elevator, for the discerning lazy feline in your life


Ah, to live the life of a cat. The lazing about, the food delivered on demand, and the elevators – oh the glorious elevators.

No you didn’t misread and we haven’t gone crazy. We were sent a link to the video below just the other day, and while it is nearly two years old, it was new to us. From the very brief description on YouTube, it looks as if the elevator senses the cat’s entry using infrared, locking the door behind the cat before transporting it to another level of the house. While it’s often implied that cats are incredibly lazy, this contraption definitely takes things above and beyond the norm.

It’s a pretty ridiculous system if you ask us, but it’s pretty compelling just the same. If you can find any more information on it, we’d love to hear about it in the comments. If you can’t, feel free to speculate as to how you would build a cat elevator, or elaborate on the crazy contraptions you’ve built for the lazy felines in your life.

[Thanks, Andreas]

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