The Quadrivium EnsembleBot Is A Labour Of Love

The Quadrivium EnsembleBot project is a mashup between old school musical instruments and the modern MIDI controlled world. Built by a small team over several years, these hand crafted instruments look and sound really nice.

The electronics side of things is taken care of with a pile of Arduinos and off-the-shelf modules, but that doesn’t mean the design isn’t well thought through, if a little more complicated than it could be in places. Control is taken care of with a PC sending commands over the USB to an Arduino 2560. This first Arduino is referred to as the Master Controller and has the immediate job of driving the percussive instruments as well as other instruments that are struck with simple solenoids. All these inductive loads are switched via opto-isolators to keep any noise generated by switching away from the microcontroller. A chain of four sixteen-channel GPIO expander modules are hung off the I2C bus to give even more opto-isolated outputs, as even the Arduino 2560 doesn’t quite have enough GPIO pins available. The are a number of instruments that have more complex control requirements, and these are connected to dedicated slave Arduinos via an SPI-to-CAN module. These are in various states of development, which we’ll be keeping our beady eyes on.

One of the more complex instruments is the PipeDream61 which is their second attempt to build a robotic pipe organ. This is powered by a Teensy, as they considered the Arduino to be a little too tight on resources. This organ has a temperature controller using an ATTiny85, in order to further relieve the main controller of such a burden and simplify the development a little.

Another interesting instrument is Robro, which is a robotic resophonic guitar which as they say is still work in progress despite how long they have been trying to get it to work. There’s clearly a fair bit of control complexity here, which is why it is taking so much fiddling (heh!) to get it work.

This project is by no means unique, lately we’ve covered controlling a church organ with MIDI, as well as a neat Arduino Orchestra, but the EnsembleBot is just so much more.

Continue reading “The Quadrivium EnsembleBot Is A Labour Of Love”

Polyphony On A Tiny Scale

Older readers may remember the Stylophone, a small battery powered electric organ using conductive PCB pads and a stylus to create notes. The simple multivibrators in those instruments made them monophonic, but here in 2021 we can do better than that! [Sjm4306] has gone the extra mile with a PCB organ, by making a capacitive-touch instrument that boasts four-note polyphony.

At its heart is an ATmega328p whose software sports four tone generators that each emerge on a different pin. These are summed using a set of 100 Ω resistors and fed to a tiny speaker. Power comes from a CR2032 lithium cell, and he notes that a higher voltage delivers more volume.

The full story is detailed in the video below the break, along with a bit of four-note polyphonic action. We’re guessing that this instrument would sound sensational when hooked up to a reverb unit.

Continue reading “Polyphony On A Tiny Scale”

The Sixtyforgan Proves That Church Organs Are Definitely Chiptune

Church organs may be mechanically complicated and super old-school, but they share something in common with the earliest computer sound chips. In theory, and largely in practice, they produce very simple waveforms. The primary reason that church organs seem so full and rich compared to your old Commodore 64 is that they have the benefit of a whole church’s worth of reverb to fatten out the sound. [Linus] demonstrates this with the Sixtyforgan.

The Sixtyforgan is a Commodore 64 hooked up to a spring reverb tank. By running the relatively basic waveforms from the Commodore’s SID chip through this reverb, it’s possible to generate sounds that are eerily similar to those you might hear at your local Sunday service. While we won’t expect chiptune luminaries like [chipzel] to start busting out songs of praise at events like Square Sounds, it’s kind of awesome to think of the composers of antiquity rocking out to some mad Game Boy jams way back when.

It’s a great demonstration of the Commodore’s musical abilities, and we particularly like the application of the chromatic button layout borrowed from the accordion. We’d love to see this setup combined with an orchestra of the retro computers, like this demonstration playing The Sugar Plum Fairy. Alternatively, Billy Corgan on the Sixtyforgan playing Tiberius would be pretty great, too. Pretty sounding video after the break.

Continue reading “The Sixtyforgan Proves That Church Organs Are Definitely Chiptune”

Tonewheels Warble In This Organ-Inspired Musical Instrument

Younger readers may not recall the days when every mall had a music store — not the kind where tapes and LPs were sold, but the kind where you could buy instruments. These places inevitably had an employee belting out mall-music to all and sundry on an electric organ. And more often than not, the organist was playing a Hammond organ, with the distinct sound of these instruments generated by something similar to this tonewheel organ robot.

Tonewheels are toothed ferromagnetic wheels that are rotated near a pickup coil. This induces a current that can be amplified; alter the tooth profile or change the speed of rotation, and you’ve got control over the sounds produced. While a Hammond organ uses this technique to produce a wide range of sounds, [The Mixed Signal]’s effort is considerably more modest but nonetheless interesting. A stepper motor and a 1:8 ratio 3D-printed gearbox power a pair of shafts which each carry three different tonewheels. The tonewheels themselves are laser-cut from mild steel and range from what look like spur gears to wheels with but a few large lobes. This is a step up from the previous version of this instrument, which used tonewheels 3D-printed from magnetic filament.

Each tonewheel has its own pickup, wound using a coil winder that [TheMixed Signal] previously built. Each coil has a soft iron core, allowing for the addition of one or more neodymium bias magnets, which dramatically alters the tone. The video below shows the build and a demo; skip ahead to 16:10 or so if you just want to hear the instrument play. It’s — interesting. But it’s clearly a work in progress, and we’re eager to see where it goes. Continue reading “Tonewheels Warble In This Organ-Inspired Musical Instrument”

Wurlitzer Note Visualizer Gets A 2020-Spec Replica

Way back in the 1970s, when smog laws were choking American V8s and the oil crisis was in full swing, Wurlitzer released their Key Note Visualizer. Intended as a teaching aid, the device lit up keys on a keyboard graphic, allowing an organ player to visually demonstrate their performance to a class. [Guy Dupont] set out to replicate this hardware, but with a modern twist.

The build consists of an ESP-32, which accepts MIDI data over Bluetooth Low Energy. This is then used to light up a series of RGB LEDs on a musical staff and a keyboard graphic, corresponding to the notes being played. The LEDs used are the old-school four-wire type, rather than more modern data-driven types. They’re placed in 3D-printed holders which serve to stop the light from each LED bleeding into adjacent areas. The faceplate is made of acrylic, stencilled with that classic orange paint and with vinyl decals applied for the markings. It’s all wrapped up in a walnut case, which [Guy] CNC machined himself.

It’s a tidy build that faithfully recreates the 1970s aesthetic of the original. We plaintively wish that manufacturers would release more electronics in walnut enclosures, though ask politely that they leave cheap veneer in the past where it belongs.

Of course, if you like your musical displays more abstract than instructional, try this giant oscilloscope visualisation on for size. Video after the break.

Continue reading “Wurlitzer Note Visualizer Gets A 2020-Spec Replica”

Be Still, My Animatronic Heart

Fair warning for the squeamish: some versions of [Will Cogley]’s animatronic heart are realistic enough that you might not want to watch the video below. That’d be a shame though, because he really put a lot of effort into the build, and the results have a lot to teach about mimicking the movements of living things.

As for why one would need an animatronic heart, we’re not sure. [Will] mentions no specific use case for it, although we can think of a few. With the Day of Compulsory Romance fast approaching, the fabric-wrapped version would make a great gift for the one who stole your heart, while the silicone-enrobed one could be used as a movie prop or an awesome prank. Whatever the reason, [Will]’s build is a case study in incremental development. He started with a design using a single continuous-rotation servo, which powered four 3D-printed paddles from a common crank. The four paddles somewhat mimicked the movements of the four chambers of the heart, but the effect wasn’t quite convincing. The next design used two servos and complex parallelogram linkages to expand each side of the heart in turn. It was closer, but still not quite right.

After carefully watching footage of a beating heart, [Will] decided that his mechanism needed to imitate the rapid systolic contraction and slow diastolic expansion characteristic of a real heart. To achieve this, his final design has three servos plus an Arduino for motion control. Slipped into a detailed silicone jacket, the look is very realistic. Check out the video below if you dare.

We’ve seen plenty of animatronic body parts before, from eyes to hands to entire faces. This might be the first time we’ve seen an animatronic version of an internal organ, though.

Continue reading “Be Still, My Animatronic Heart”

Additive, Multi-Voice Synth Preserves Sounds, Too

For his final project in [Bruce Land]’s microcontroller design class, [Mark] set out to make a decently-sized synth that sounds good. We think you’ll agree that he succeeded in spades. Don’t let those tiny buttons fool you, because it doesn’t sound like a toy.

Why does it sound so good? One of the reasons is that the instrument samples are made using additive synthesis, which essentially stacks harmonic overtones on top the fundamental frequency of each note. This allows synthesizers to better mimic the timbre of natural, acoustic sounds. For each note [Mark] plays, you’re hearing a blend of four frequencies constructed from lookup tables. These frequencies are shaped by an envelope function that improves the sound even further.

Between the sound and the features, this is quite an impressive synth. It can play polyphonically in piano, organ, or plucked string mode through a range of octaves. A PIC32 runs the synthesizer itself, and a pair of helper PIC32s can be used to record songs to be played over. So [Mark] could record point and counterpoint separately and play them back together, or use the helper PICs to fine-tune his three-part harmony. We’ve got this thing plugged in and waiting for you after the break.

If PICs aren’t what you normally choose, here’s an FPGA synth.

Continue reading “Additive, Multi-Voice Synth Preserves Sounds, Too”