Fabbing A Guitar Tremolo Stompbox

November 29, 2011 by Brian Benchoff 20 Comments

There’s a lot of builders around whose first foray in electron manipulation was building effects pedals for guitars. It looks like [Dino] might be getting back to his roots with his tremolo effects box how-to.

Last week, [Dino] found an old 5-watt tube amp in someone’s trash and decided to bring it back to a functional state. With his new trem effect, it looks like [Dino] might be getting the band back together.

Apart from tiny boost circuits, a tremolo is generally the simplest effect pedal you can make. All you’ll need to do is vary the amplitude of the guitar’s signal at regular intervals. After that, it’s only a matter of pretending you’re playing through a rotating Leslie speaker.

To get his trem working, [Dino] set up a 555 circuit to flash a LED at regular intervals. This LED is encased in heat-shrink tubing along with a photocell. This setup controls an LM386 amplifier. The build is really simple, but from the video after the break we can tell it sounds great.

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A Trojan Horse Full Of Music

November 25, 2011 by Brian Benchoff 1 Comment

With a Sound + Vision exhibition coming up, the folks over at Seaweed Factory decided they needed something big. Somehow they landed on building a giant pinata that responds to being walloped with a stick by playing MIDI notes. The end result is called the Trojan Chorus. Instead of Greek soldiers, though, the pinata is filled with electronics and candy.

The pinata was constructed out of cardboard and more colored tissue paper than we care to imagine. The horse stands seven feet tall and was built with a little more structural integrity than a normal pinata. Check out the ‘making of’ video for the pinata here.

From what we can tell, the electronics are 24 contact microphones implanted all over the inside of the pinata. Impacts on these contact mics are recorded by a small dev board, transcribed to serial data, and sent to a computer. You can check out the electronics in action right here. A horse neighing MIDI notes may sound fairly weird, but similar setup could be added to make the Trojan Chorus cry out in pain.

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A Doorbell Pleasing To Both The Ears And Eyes

November 22, 2011 by Mike Nathan 15 Comments

campanello-doorbell

When [David] moved into his new house, one of the things he noticed was that his doorbell was pretty lame. Coming from a home equipped with a solenoid and chime bell, his new wireless solid state doorbell sounded terrible to him.

Crummy sound aside, the doorbell hardly ever worked properly, but alas, other projects cropped up and years went by before [David] addressed his doorbell problem. Like many things that take a long time to come to fruition, we think his resonator bell based solution was well worth the wait.

One of his main goals was to make a nice sounding doorbell that also looked great. He mounted a kid’s resonator bell toy on a sheet of wood, creating his own wooden mallets for the job. He initially had a tough time locating actuators for his doorbell, but found a solution in geared pager motors as featured in another xylophone hack on Make. With the hardware taken care of he focused on the electronics, which consist of a pair of Arduino clones – one on the display and one in his basement.

Stick around to see [David’s] Campanello doorbell in action, and be sure to check out his site for more details if this sounds like something you would like to have in your home.

[via Make]

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Junkyard Tube-amp Gold!

November 21, 2011 by Mike Szczys 20 Comments

Why, oh why, oh why do people toss out awesome retro hardware?? Luckily, [Dino] visited the junk depot himself at just the right time. Even though you’re not supposed to take things others have dropped off he poached the retro portable turntable that was just sitting there. He cracked it open and figured out how to turn it into this great tube guitar amp without going to all that much trouble.

The original turntable used to be where the front grates are in the image above. The guitar amp version sits the case on end, which works perfectly since the carrying handle is now on the top. This orientation would have put the amplifier hardware upside down, so [Dino] pulled it out and flipped it around. The speakers for the turntable were made to sit separately and be connected with wires. But they also doubled as a lid for the unit. This makes them the perfect size to fit side-by-side in the void left by the turn table.

[Dino] records his own music for the build video after the break using his new hardware. Sounds great, looks great, and it was saved from being needlessly buried in the ground. Fantastic!

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Electronic Recorder Conversion

November 16, 2011 by Mike Szczys 19 Comments

As we wrote the title to this feature we can see why [Jeff Ledger] calls it an electronic flute and not a recorder; this is a musical instrument and not something for archiving audio. Confusion aside, we’re all familiar with these plastic ‘musical’ instruments. Many elementary schools in our area require students to buy one as part of music class. So it shouldn’t be hard to find one if you want to try this for yourself (heck, [Jeff] grabbed his a the dollar store).

Basically, he’s replaced the finger holes with momentary press switches, then uses a Propeller dev board to turn the button presses into music. It’s simple and quick, but what does it for us is the breath actuator. Sure, you can set this up to play whenever a button is depressed, but [Jeff] went that extra mile and added a piezoelectric element to the bottom. When you blow through the instrument it flexes slightly, generating a tiny current that can be measured by the microcontroller. Check out the short clip after the break.

Do a little more work and you could turn this into some type of musical game controller. We’re thinking Zelda!

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Bullhorn Mod Lets You Disperse Angry Crowds To The Dulcet Tones Of [Kenny G]

November 10, 2011 by Mike Nathan 11 Comments

megaphone-mod-aux-audio-in

[Randy] had a cheap megaphone, and like most models in this price range, it didn’t have an audio input jack on board. He wanted the ability to pipe both music and audio from an external mic through the megaphone, and in a brief tutorial, he shows how he modified his bullhorn to do just that.

Most megaphones carry their electronics near the built-in mic, just outside the battery compartment. Removing the screws from the cap in [Randy’s] model revealed a circuit board and a couple of wires connecting it to the on board mic. His megaphone happened to play some canned music from a secondary circuit board, and he spliced in an audio jack with a built in cutoff switch between that and the main PCB. He also added a resistor in between his jack and the microphone circuitry to attenuate the line level signal properly. Once he reassembled everything, and then tested his input using a portable audio player, slowly ramping up the volume to the desired level.

It’s not every day that you require the ability to blast music through a bullhorn, but [Randy’s] modification is a great addition when you do need it.

Arduino-based MIDI Synth

November 8, 2011 by Mike Szczys 2 Comments

[Charles Gershom] has been tinkering around with his keyboard and Arduino in order to build his own version of a MIDI controlled synthesizer. It looks like he’s gutted the enclosure of some commercially available MIDI hardware to use for the project. This works nicely since it gives him both the MIDI and audio jacks that he needs. The box also provides a nice control surface where a set of four LEDs indicates the synth mode currently in use. There are also four potentiometers mounted on the panel, but they’re not yet up and running.

Check out the video after the break to see what this can do so far. [Charles] shows the device synthesizing sounds coming in from the keyboard. It is also used to playback the audio from Super Mario Bros. which is fed in by a music notation program on a computer. Only one voice is playing when this happens which makes us think this can only handle one channel at a time right now (but we could be wrong).

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