An ARM-Based DSP Modelling Synth

June 14, 2014 by Brian Benchoff 42 Comments

synth

The great analog synths of Moog, Oberheim, Sequential Circuits, and more modern version from Doepfer are renouned for their sound, the sheer majesty of a rack full of knobs and plugs, and of course the price. Analog synths are simply expensive to build, and given that aficionados even scoff at digitally controlled oscillators, require a lot of engineering to build. [Jan]’s DSP-G1 isn’t like those analog synths – it uses microcontrollers and DSP to generate its bleeps and boops. It is, however, extremely cheap and sounds close enough to the real thing that it could easily find a home between a few euroracks and CV keyboards.

plug The heart of the DSP-G1 is a micro from NXP modeling an analog synthesizer with 15 digitally controlled oscillators with Sine, Triangle, Pulse and Saw outputs, a low frequency oscillator, two envelope filters, and a low pass filter, or about the same accouterments you would find in a MiniMoog or other vintage synth from the 70s. Since this is basically a synth on an NXP LPC-810, [Jan] has packaged it in something akin to a MIDI to 3.5mm cable adapter: Plug a MIDI keyboard into one end, an amp into the other, and you have a synth smaller than the MIDI Vampire, an already impossibly small music creation tool.

[Jan] has a few more versions of his little DSP device with varying amounts of knobs available on his indiegogo campaign. The DSP-Gplug is the star of the show, though, provided you already have a MIDI keyboard with a few knobs for the required CC messages. Videos and sound demos below.

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Tempo Keeping Drummer Leaves Viking Ship, Now Inspires Pedallers

June 13, 2014 by Rich Bremer 12 Comments

Bike Controlled Drum Machine

[Serdef] wrote in to tell us about a project he has recently created. It’s a drum beat generator that changes tempo depending on how fast you pedal your bike. This flies directly in the face of using music to keep your pedal timing consistent and up to speed.

The project started out with a tap-tempo drum rhythm pedal that [Serdef] had previously built. This device will generate a drum beat at a tempo corosponding with the time between 2 input signals. This type of device allows someone, say a guitarist, to quickly and easily specify the speed of the drumbeat that they are playing along with.

With the meat and potatoes of the project already figured out, the next part was to make the speed of the bike trigger the tempo of the drum beat. For the signal input, a magnet mounted on the wheel triggers a reed switch mounted on the bike fork once per wheel revolution. This is the same method of information gathering that a bicycle speedometer/odometer uses.

The business part of this project includes an Arduino that measures the speed of the wheel via the magnetic switch, adjusts the speed of the drum beat, and then sends the drum beat to a synthesizer via MIDI protocol. The synthesizer converts the MIDI signal into drum sounds amplified through a powered speaker that the rider can hear. The entire system is powered by a 9v battery and housed in a project box strapped to the bike’s handlebars.

All of the design files and Arduino code are available via [Serdef’s] excellent write up on hackaday.io in case you’re interested in making one for yourself.

MIDI Melodies Make Moody Milieu

June 12, 2014 by Kristina Panos 10 Comments

MIDI piano lights

In this beautiful, well-documented, cat-assisted hack, [capricorn1] adds visual dimension to his impressive piano skills by using his keyboard’s MIDI output to drive Edison bulbs.

He hung them from a rod of electrical conduit pipe and threaded the wires through it to a DB25 connector. The lights are controlled by an Arduino Mega plus a custom shield with an optocoupler to handle zero cross detection. He happened to already have a board with 12 SSRs on it from another project. All of the electronics are in a re-purposed switch box—the switches control four different modes: classic, velocity, scrolling, and automatic. You’ll see the scrolling mode in the video after the jump.

[capricorn1] used a small sampling of the Arduino MIDI Library, namely the note on/off functions and the control change function to handle his sustain pedal. He’s listed the full code for the project, which includes usage of the ipMIDI module for automation over WiFi.

If you don’t have a MIDI keyboard or any Edison bulbs, you could make a MIDI floor piano. You’re required to play both “Chopsticks” and “Heart and Soul” on it, though. Those are like the Hello, World for floor pianos.

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Soda Can Theremin Made In Minutes

June 1, 2014 by James Hobson 18 Comments

Looking for a fun weekend project? How about building your very own sci-fi Theremin using just a soda can and a few simple components you probably already have.

Not familiar with Theremins? It’s an electronic instrument that can be played without any physical contact. Essentially, the antenna (soda can) acts as half of a capacitor — your hand acts as the other. By varying the distance of your hand to the soda can, you change the capacitance, which can then be used to modulate a sound. It was invented in 1928 by the Russian inventor [Leon Theremin], and you can actually see a video of him playing it on YouTube — we’ve never seen this before, but we must say it’s actually quite impressive!

Anyway, back to the hack. All you need are some op-amps, a few capacitors, some resistors, a diode, a breadboard, and of course — a speaker. [Will’s] gone into great detail in how each circuit works with both schematics and diagrams of the breadboard configuration — it’s a great little project even kids can follow along.

Take a listen after the break.

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PVC Percussion Pipe Organ Sounds Surprisingly Good!

May 25, 2014 by James Hobson 31 Comments

PVC Instrument

Using over 20′ feet of PVC pipe, a whole bunch of 2 x 4’s and a few nuts and bolts, [Jeremy] and his cousin put together a rather unique percussion pipe organ.

[Jackson], his cousin who is a musician is always looking for different ways to make music. They had a rough idea of what they wanted to do with a few sketches, but after a day of tinkering, they ended up with something completely different — but it sounds awesome.

The frame is made of a combination of 2 x 6’s and 2 x 4’s which hold the PVC tubes in place. PVC elbows and varying lengths of pipe create a wide range of rather deep bass notes. It can be played with just your hands, or even a pair of sandals for better effect. You’d be surprised how good it sounds.

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5-Gallon 5-Piece Electronic Drum Set

May 22, 2014 by Rich Bremer 6 Comments

Who hasn’t wanted to rock out on some drums in the middle of the night? If you have anything that resembles neighbors then a midnight jam session is out of the question. That is unless a set of electronic drums is available… but alas, those are expensive. If you don’t have the spare cash burning a hole in your pocket, then be like [Mike] and build a complete 5 piece e-drum set.

[Mike] started off with 5 gallon buckets that would become the drum shells. On a real drum set, all of the drums are different sizes in order to produce different notes. Drum size doesn’t matter with an electronic drum as a drum module creates the note and sound. Even so, to make this set a little more realistic, each drum was sectioned and pulled back together to change the diameter. A homemade circle cutting jig and a wood router were used to cut top and bottom rim hoops out of 3/4″ plywood. The inner diameter of these hoops were made just a hair larger than the outer diameter of the 5 gallon bucket shells. The bottom of the top hoop was then routed to produce a groove which would allow a standard mesh drum head to fit inside.

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Popmaskinen — An Electromechanical One Man Band

May 21, 2014 by James Hobson 8 Comments

one man band

The Stockholm Mini Maker Faire 2014 has just finished up, and [Johnny Eriksson] was awarded the Maker of the Year award for his very impressive electromechanical one man band.

As a musician/electrician/furniture carpenter, [Johnny] has quite a few skills — and he wanted to try putting them altogether for a project. He calls it the Popmaskinen (the pop machine).

Using MIDI keyboards, buttons, and knobs, the Popmaskinen translates digital outputs to physical instruments controlled by various electromechanical components. One of our favorite parts is the guitars, which use solenoids to strum, and even more solenoids to squeeze various cords on the pair of guitars.

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