Auxiliary Display For Beat707 Works Via I2C

July 26, 2011 by Mike Szczys 8 Comments

Bigtime is a simple way to create an auxiliary display for the Beat707 MIDI controller. The right half of the display shows the beat pattern that the drum machine is using, while the left half keeps track of the current measure.

Just a few components went into the extra hardware. A four-digit seven segment display is fed data from an ATtiny85. Since that microcontroller has only eight pins, a 595 shift register and CD4067 take care of translating serial data into the outputs necessary to light the display. The entire thing connects to the Beat707’s I2C bus, which means you don’t need to make hardware alterations to the original, and this leaves plenty of room for more addons.

The code package includes a Fritzing file, but for your convenience we’ve embedded a PNG of the hardware connections after the break. You’ll also find the demo video where [Guilherme] explains how this works.

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Guitar Becomes An Improved Color Organ

July 24, 2011 by Brian Benchoff 12 Comments

[Charles] wanted to put some LEDs in his guitar. He also wanted individual notes to output certain colors, but he couldn’t find any projects with tone-based algorithms to convert sound into colors. After about a year of work, his ColorChord guitar was born.

Unlike every other color organ build we’ve seen, the color of a note does not relate to the absolute pitch of the note. Instead, the colors are mapped within a musical key. A I chord will always be Yellow, a IV chord will always be purple, and a V chord will always be blue. Playing in the key of C will have the LEDs output yellow, purple, and blue for a C, F and G chord, respectively.

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Creating Music From GPU Noise

July 24, 2011 by Mike Szczys 27 Comments

Yep, that’s a picture of a Laptop rocking out on an electric guitar. In what can only be described as a truly bizarre hack [CNLohr] discovered that the RF noise from the computer can be used to play music through the guitar’s pickup.

Check out the clip after the break to hear an annoying, but very discernible rendition of Jingle Bells. Once [CNLohr] stumbled onto the fact that changes in what the graphic processing unit is doing was affecting the pitch detected by the pickup he started writing some code. Now he’s got a program that automatically calculates the size of the window, and produces a white square on a black background to dial in the GPU at the right frequencies.

He mentions in the notes accompanying his video that he had to turn off Vsync to get this to work right. We don’t understand why but we’d love to hear what you think in the comments.

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Followup: Portable SID Player Is Now PC Output

July 20, 2011 by Brian Benchoff 9 Comments

When we first covered [Markus]’ portable SID player we starting dreaming about an alternative universe circa 1987 that included a pocket-sized music player called the Commodore ePod. [Markus]’ updated firmware that connects his SID player to a PC will have to do for now, we suppose.

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FPGA Generated SPDIF Output

July 12, 2011 by Mike Szczys 13 Comments

[Mike Field] just finished implementing SPDIF generation on an FPGA. SPDIF is an industry standard for transmitting digital audio signals; the acronym stands for Sony/Philips Digital Interconnect Format. It’s been around for more than a decade and since it’s found on most home-audio equipment, building an SPDIF output into your projects may be quite a desirable feature. [Mike] mentions several ideas for this functionality like building high-end test equipment, or providing a high-quality output for electronic instruments.

He first jumped into analyzing the specification in order to determine the hardware requirements. Due to some issues with jitter, he found it necessary to use a 100 MHz clock signal. This pushes the jitter down to +/- 5ns of jitter, which he concedes may raise the hackles of audio purists, but does satisfy the published standard. Output requires just one pin of the FPGA and the five components seen above. A hex inverter (74HC04) voltage divider, capacitor, and RCA connector transmit the 0.5V signal to your audio-receiver of choice. Of course, since TOSLINK fiber optic connectors use the same protocol, you could redesign the output and make this an optical connection.

Stereo Amplifier With Digital Volume Control

June 27, 2011 by Brian Benchoff 10 Comments

A regular Hack A Day reader sent in a tip about an LM386 stero amplifier with digital volume control. The resulting build is very professional and could easily be adapted into a slick iPod dock build.

We’ve seen a few LM386-based amplifiers over the years including one that fits inside a 9V battery, but this is the first implementation of digitally controlled volume we’ve seen. The volume control of this amp uses the DS1868 dual digital pot IC in place of the usual 10K pot providing 256 steps between zero and full volume. The DS1868 is controlled by a PIC μC with a 3-wire serial connection, although this could be implemented on any microcontroller.

Although the code provided with this build outputs volume as a linear function, it would be trivial to implement a logarithmic volume output. Because the ear perceives loudness on a logarithmic scale, this would be a great way to adjust audio volume and provide a more fine-grained control. Of course this could be implemented with a logarithmic pot, but where’s the fun in that?

Check out a video of the amp after the break.

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Synapse Turns Your Kinect Into A Dubstep Theremin

June 23, 2011 by Mike Nathan 12 Comments

kinect_dubstep_theremin

[Ryan Challinor] is part of a group constructing a display for this year’s Burning Man festival that includes the Kinect, Ableton Live, and Quartz Composer. As the programming guru of the project, he was tasked with creating a method for his partners to utilize all three products via an easy to use interface.

His application is called Synapse and was inspired by videos he saw online of people controlling individual Dubstep beats or sound effects with the Kinect. Synapse allows you to map multiple effects to each limb, sending joint positions, hit events, and image depth data to both Ableton and Quartz Composer via OSC. The user interface looks fairly easy to work with, enabling musicians and artists to create awesome audio/visual displays using their bodies as instruments, in a very short period of time.

Check out the pair of videos below to see a brief walkthrough of the software interface as well as a quick video demonstration of what Synapse is capable of.

[via KinectHacks]

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