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A classic one-man band generally features a stringed instrument or two, a harmonica in a hands-free holder, and some kind of percussion, usually a bass drum worn like a backpack and maybe some cymbals between the knees. The musician might also knock or tap the sound-boards of stringed instruments percussively with their strumming hand, which is something classical and flamenco guitarists can pull off with surprising range.

The musician usually has to manipulate each instrument manually. When it comes to percussion, [JimRD] has another idea: keep the beat by pounding the soundboard with a solenoid. He built a simple Arduino-driven MOSFET circuit to deliver knocks of variable BPM to the sound-board of a ukulele. A 10kΩ pot controls the meter and beat frequency, and the sound is picked up by a mic on the bridge. So far, it does 3/4 and 4/4 time, but [JimRD] has made the code freely available for expansion. Somebody make it do 5/4, because we’d love to hear [JimRD]  play “Take Five“.

He didn’t do this to his good uke, mind you—it’s an old beater that he didn’t mind drilling and gluing. We were a bit skeptical at first, but the resonance sweetens the electromechanical knock of the solenoid slug. That, and [JimRD] has some pretty good chops. Ax your way past the break to give it a listen.

Got a cheap ukulele but don’t know how to play it? If you make flames shoot out from the headstock, that won’t matter as much. No ukes? Just print one.


Filed under: Arduino Hacks, Musical Hacks

In a well documented blog entry, [Loren Bufanu] presents a project that lit up a glass dance floor covering a swimming pool with RGB strips. We mentioned a video of his project in a Hackaday links but didn’t have any background information. Now we do.

boards in boxThe project took around 450 meters of RGB strips controlled by two Rainbowduinos and driven by sixty-four power Mosfets, sixty-four bipolar transistors, and a few other components. Running just the white LEDs draws 8 amps of power.

The Rainbowduino is an ATmega328 Arduino compatible board with two MY9221 controllers. Each  controller handles 12 channels of Adaptive Pulse Density Modulation. In other words, it makes the LEDs flash nicely. [Loren] used the Rainbowduino instead of some alternatives because multiple R’duinos can coordinate their activities over I2C.

The software part of the project did not work as well as the hardware. The light patterns were supposed to follow the music being played. A PC software package intended to drive the R’duinos produced just a muddy mess. Some kludges, including screen captures (!), driven by a batch file tamed the unruliness.

It’s been awhile, but a similar disco dance floor, built by [Chris Williamson] but not over a pool, previously caught our attention. [Chris] is a principle in Terror Tech that recently got a mention on Sparkfun.

The video after the break fortunately does not make a big splash, but is still electrifying.


Filed under: Arduino Hacks, led hacks


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