Fubarino Contest: Single PCB Synth

fubarino-contest-synth

Here’s a musical entry for the Fubarino Contest that turned out to be rather delightful. First, [Mats] shows off his musical knowledge by using the notes H, A, and D to play the chord that unlocks the Easter eggs. What’s that you say? There’s no H on your keyboard? You’re wrong. In the German music tradition B natural is known as H. This is what allowed Bach to write a tune that spells his name.

[Mats] is hacking on his PlingPlong synthesizer. The first Easter egg—which you can see in the clip after the break—launches with the H-A-D chord in the lower octave, spelling out our URL on the 7-segment displays. But we prefer the second egg, launched with the chord in the upper octave, which is shown above. It uses the 3×5 LED grid to scroll out the address; in this still image an H is displayed.


This is an entry in the Fubarino Contest for a chance at one of the 20 Fubarino SD boards which Microchip has put up as prizes!

IR Theremin Speaks In Four Voices

infraredTheremin

At the end of every semester, we get a bunch of cool and well-documented student projects from Cornell’s ECE4760 class. [Scott] and [Alex]’s infrared theremin is no exception.

The classic theremin design employs each of the player’s hands as the grounded plate of a variable capacitor in an LC circuit. For the pitch antenna, this circuit is part of the oscillator. For the volume antenna, the hand capacitor detunes another oscillator, changing the attenuation in the amplifier.

[Scott] and [Alex] put a twist on the theremin by using two IR sensors to control volume and pitch. The sensors compute the location of each hand and output a voltage inversely proportional to its distance from the hand. An ATMega1284P converts the signal to an 8-bit binary number for processing. They built four voices into it that are accessible through the push-button switch. The different voices are created with wave combinations and modulation effects. In addition to Classic Theremin, you can play in pure sine, sawtooth, and FM modulation.

If you’re just not that into microcontrollers, you could build this digital IR theremin instead. If you find IR theremins soulless or plebeian, try this theremincello.

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An Opensource Arduino Guitar Pedal

If you’re a guitarist, or know a guitarist, you probably know just how many guitar effects there are out there — but what if you could design your own effects?

[J Rodriguez] has just released his opensource Arduino guitar pedal shield, dubbed the pedalSHIELD. He designed it as a platform to learn about digital signal processing, effects, and synthesizers — without needing an in-depth knowledge of electronics or programming. It allows you to design your own effects in C/C++, or download from his own library online. Some of the downloadable presets include an octave pedal, reverb pedals, delay pedals, and even distortion pedals!

The pedal features three programmable potentiometers, two main switches, and the foot pedal switch. The shield plugs directly into an Arduino Due, and you can find all the schematics here and the parts list here. It was completely designed in KiCad which is an open source electronics CAD design suite.

Take a listen after the break to hear the pedal in action!

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Cryophone: A Dry Ice-Powered Musical Installation

cryophone

[Dmitry] is a bit of an industrial artist / hacker, and he’s recently finished this interesting and interactive audio exhibit called the Cryophone.

As you know, dry ice is terribly fun. When placed in water, it sublimates from its solid to gaseous phase rapidly, releasing carbon dioxide gas and causing a drastic (and sometimes violent) temperature change. [Dmitry’s] project attempts to amplify the sounds of these reactions and create music(?) using data from sensor inputs in the system. He uses piezo elements, temperature sensors, and an Arduino to generate an algorithmic composition from the various sensors, which a Mac Mini then synthesizes and outputs as audio in 6 channels.

The result is an eerie collection of noises that would do well in a haunted house or a horror movie. Take a listen for yourself after the break, and if you missed it, check out another unique, audio-based art installation: ‘conus.’

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Analog Drum Machine

Drum Machine Schematic

This analog drum machine project synthesizes a kick and snare drum that are clocked to a beat. It pulls together a few analog circuits to do the timing and synthesis.

The beat timing is a product of a hysteretic oscillator used to create a ‘shark wave,’ which is a friendly term for the output of a relaxation oscillator. This waveform can be compared to a set point using a comparator to create a slow square wave that clocks the drum beat.

The kick drum is synthesized using another hysteretic oscillator, but at a higher frequency, creating a triangle-like waveform at 265 Hz that provides a bass sound. The snare, however, uses white noise provided by a BJT’s P-N junction, which is reverse biased and then amplified. You can spot this transistor because its collector is not connected.

The resulting snare and kick drum wave forms are gated by two transistors into the output. Controlling these gates allows the user to create a drum beat. After the break, check out a video walk-through and a demo of the build.

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Cast A Shadow, Play A Note

Looking for a way to entertain friends and family this holiday season? Look no further than the Arduino-powered Photocell Piano. [Asahillis] has posted this Instructable for building a 6-note musical command center.

The piano uses photoresistors to turn each note on when the player runs their hand over it. Notes can be tuned independently using potentiometers on the front of the box. The hack uses two circuits: one to generate the tones, and a second to mix them. [Asahillis] adapted [Forest Mims III]’s timeless schematics for the 555 Tone Maker and the 741 Audio Mixer to create his Photocell Piano.

When the instrument is powered on, the code takes a 5-second reading of the ambient light, and sets a threshold based on its findings. Afterward, the first note will sound, indicating the piano is ready to be played. Each note has its own if-else statement that tells it to sound when its corresponding  photoresistor reaches a value below the set threshold (when the player casts a shadow). There’s a demo video included in the guide but we couldn’t embed it here.  Check out the demo video after the break.

If you prefer to rock out with your lights out, there’s always this impressive laser harp.

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Portable Musical Stairs

musical stairs

[Amir] recently finished a pretty cool project — Portable Musical Stairs! He designed and built it so it could be temporarily installed in schools for musical therapy sessions with autistic children — a fun activity for all ages!

The system utilizes lasers and photo sensors that come with a built in digital output with a sensitivity potentiometer, which makes it super easy for the Arduino Leonardo to interpret. The reason they are using 2 by 4’s for the system is because of the width of the stairs. At 1.75m across, a laser misaligned by only 1 degree results in it being about 3cm off!

On the software end of things, the Arduino acts as a HID input to the computer to create the sounds. [Amir] has put together a free sound sampler on his website makeysoundy.com, and we must say, it’s pretty fun! You can assign notes to different keys, which makes it super easy to make a similar project to this!

Stick around after the break to see the stairs in action!

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