Build a tetrahedral ambisonic microphone

[Dan Hemingson's] been refining a design for building a tetrahedral ambisonic recording system. This is a set of four microphones used to record audio that can later be mixed down for a three-dimensional listening experience. His goal is an easy and inexpensive build while maintaining the highest fidelity standards possible. Lucky for us he’s made a set of extremely detailed build instructions you can use to make your own. In addition to the mounting bracket seen above he has also developed a pre-amp module that connects to the four mics; it’s part of the build instructions with schematic and board layout files available as well.

[Thanks Isaac]

Input device using LED and four photoresistors

[Julien] built an input device that uses reflected light detected by some photoresistors. Placing your hand above the device will reflect light from the LED back down onto the cadmium-sulfide sensors. The resistance of those sensors is read by four ADC pins on a Teensy microcontroller and translated to mouse movements. In the video after the break you can see that this works rather well in controlling the cursor. The source code is available on pastebin but we’re also going to host the code for posterity.

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Darbuka band

This robotic band has just the right amount of drums. [Liat] and her colleagues fit a group of Darbuka drums with a pair of servo-driven mallets. We’re quite surprised that the servo motors achieve such a successful strike and rebound without dampening the vibrations of the drum head. This is more often accomplished with solenoids because of their quick response and relative strength.

You can listen to a performance of this work-in-progress in the video after the break or make plans to see it live. The installment was built for the Bat-Yam international biennale of landscape urbanism. It will be attached to, and powered by alternative energy producers like solar cells and wind turbines. Continue reading “Darbuka band”

Matrix clock is a breadboarding win

Normally when we feature a clock made with a 32×8 LED matrix we’d load up an image of the display for the banner photo. But this time around we were so impressed by [JB's] breadboard work we had to use this image. We see an ATmega168, three buttons, three LEDs, a piezo buzzer, 32.768 kHz crystal, smoothing capacitor, and a few resistors; everything he needed to keep time and display it on the matrix module. If this is just going to sit on your bookshelf for a while it’s a great alternative to point-to-point soldering on a protoboard. Nice work fitting it all on there [JB].

Audio ads in newspapers?

Oh no, lets hope this little gimmick doesn’t catch on. Volkswagen has put out an advertisement in an Indian newspaper that plays an audio file when you unfold the paper. This appears to work much like those greeting cards that play a song when you open them. There’s a sensor that detects the newspaper opening, probably just a piece of plastic or paper that slides out from between two contacts. This allows power to the circuit and the audio file is played.  Can you imagine how obnoxious this could be? Especially if your newspaper was riddled with these and those E-paper screens.  Then again, that speaker looks like massive overkill for this kind of thing and might be a decent piece electronics to keep in the reuse bin. You can see a video of the newspaper after the break.

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