Alternate Simplified Controller for the rest of us

Those who didn’t spend countless hours in their youth learning piano and music theory may be in awe of those who can improvise melodies and change keys on the fly.
Something with a single key or simpler scale may be more comfortable for for the casual player.
(In a new video, Jordan Rudess describes discovering his gift, first improvising chopsticks at 7 and auditioning for Julliard at 9, he’s not one who needs a simplified instrument)

Little Mirimba

A coupe of examples, using alternate thumbs works well with the Mirimba’s tuning.
The Hand Pans played by professionals are quite expensive, (not practical to have one in every key like harmonicas)
The one shown has SALADIN - Tuning: D / G A C D Eb F# G A
Pianoteq has a Hand Pan instrument, which you could trigger from your keyboard’s drum pads to get a more authentic feel for the dynamics.

Simplified scales that have been used in popular music include:
Heptatonic scale 7 note western scale C D E F G A B C…
The Pentatonic 5 note sub scale C D E G A C… (omits tense 4th & 7th from major scale) has appeared in a number of popular songs. (the 5 black keys in a piano octave are in a Pentatonic scale)
Tom Hanks Big Piano
Bobby McFerrin plays the audience, sort of like Tom Hanks in Big, to illustrate the Pentatonic scale in a panel discussion.

The Theremin looks simple at first, but unlike simplified instruments limiting your note choices, you have infinite choices with a Theremin, they are a challenge to master.
One DIY Theremin I recently noticed is the “Altura MkII Theremin MIDI Controller Arpeggiator DIY Kit

It uses ultrasonic sonar in place of the original radio circuit. (An older Github source page)
It’s Arpeggiator mode plays just proper notes.
This youtube video guy demonstrates it with a 5 part song
Moog has produced several fairly faithful reproductions of the Theremin, here’s a demo of the model with MIDI CC outputs.

Another commercial product I just ran across is the Orba, puck shaped music maker.

Selling for $99.99 it has 8 keys and tilt shake input. It has Bluetooth MIDI and can do sequencing. (They previously offered the Music 1 a guitar neck like controller with 72 pad switches. (Not sure if they are being marketed, I did see a used one for $400)

One of the countless projects at Adafruit was the Trellis M4 Expressive MIDI Controller kit.
rellis M4 Expressive MIDI Controller
With an 8x4 switch matrix as well as motion sensing.


Hi @MaxMaxis!

I just released the ZynFace kit, that includes a funny feature that can be used for implementing something similar to the ALTURA on the zynthian:

I’ve not publicited the release too much because documentation is not ready yet, and i would like to improve the software and make some nice video. Too many things over my desk … :sweat_smile:


1 Like

Cheap controller device experiments. The Zynthian seems like a good voice for experimental controllers.

A couple of projects I have seen out there.

A Flintstones style Pitch-Modulation control, using an Arduino Computer and and external ADC. (A modern 32 bit microcomputer board for $6 can match this with their built in ADC converters. In fact the SAMD21 I have been using (also used in the Raspberry Pi Pico) has a 12 bit ADC that can be oversampled for up to 16 bit resolution, at the cost of speed.

Someone put together this demo of the Accelerometer built into cell phones, being used as a Wah Wah Pedal by strapping the phone to one’s foot. I believe the demo web page accesses an iPhone’s accelerometer with javascript.
The Demo Page - - - - - The Github Sorce
You could make this work as an input device for your Ztnthian (Don’t stomp too hard)

Another pedal form I considered.
Sponge Pedal smaller
Providing you have some sort of motion sensor like a BLE fitness monitor, M5StickC or conference badges I have seen strapped to your foot, you would have a sort of parlor trick. (It’s guranteed that a gadget wired to your foot will end up yanking wires or pulling down equipment racks sooner or later, a more complicated and slower bluetooth interface is the way to go)
I tested a USB wired foot angle detector using $8 in parts.
XIAO & MPU-6050
Testing it with the standalone version of the Vital synthesizer plugin.
Here’s a botched video demo.

I learned that while the Vital mod wheel input accepts 14 bit MIDI control signals, the macro dials only handle 7 but res. input.

While I am mostly interested in making expression controls.

I previously posted a cheap USB breath control sensor and the Wii Numchuck with a simple to use I2C inteface, I got a couple of these in a Walmart clearance for $3, is there a problem with candy apple pink?
With 2 pushbuttons, a joystick and accelerometer, it might be useful to select patches, etc. A pro might no want to look like they are playing Guitar Hero in a paid gig…

I did make this test using an IMU attitude sensor for note selection, Along the lines of the Altura-MIDI-Theremin’a arpeggiator, I adapted a Harmonica Diatonic scale to globe shaped input device, hoping the shape would provide a stronger position reference.

  • Rotating the ball parces through the note table horizontally.
  • Tilting forward-back selects a Blow-Draw row of notes.
  • Tilting right opens the embouchure, so more adjacent notes play at once.
    The musical merits are questionable, trying to keep track of 3 axis of rotation while operating it is is tricky.
    I will have a recorded demo shortly…

This is using the same $6 computer and $2 IMU sensor as the pedal experiment. I just ran across a nicely packaged driver for the MPU-6050 that includes code for the internal DMP (Digital Motion Processor) that applies sensor fusion to provide a more steady output. This special code typically had to be requested from the chip maker (not using your gmail address) this library makes it simpler to use. This code can output QUATERNIONs a complex system that can represent angles. (Normal XYZ Euler angles are subject to “Gimbal Lock” a singularity condition that drops data.
Gimble Lock Textˆ
Quaternions used in science and video game design uses 4 units of measure to avoid gimbal lock, (the math is incomprehensible to me, thankfully there are friendly conversion routines)
The simplest motion sensor, like cell phones and the Wii Numchuck uses is the Accelerometer, which despite the name are best for measuring static orientation. The name sounds like it would be used in inertial navigation like ships and planes use. But these micro machines are not accurate enough, error quickly accumulate in the double integration calculations, they are OK for sensing quick gestures.

MPU-6050 Teapot Example Video rendered by the Processing app.

The “Teapot” demo using a simple 3D plan is included with the MPU-6050 driver, I tried to go through the 3 Axis Roll-Pitch and Yaw, most noteworthy, the sensor fusion processor provides a stable Yaw (heading) despite having no stable reference, it’s just counting up gyro changes. The demo is using Quaternions so one should not be able to induce gimbal lock.
Accelerometer compute orientation by referencing earth’s gravity, which makes a static sensor appear to be moving away from the surface at 1 G. This is good for Pan and Tilt angles (in aeronautic terms) but the Yaw (heading) doesn’t have a stable reference, 9 degree of freedom (9-dof) sensors include a magnetometer, which allows magnetic compass headings to be read. The vintage MPU-9250 is an example 9 DOF IMU that includes a 3D magnetometer. They can be bought from China for about $3.50, a newer example, the TDK-InvenSense ICM-20948 who’s internal motion processor can do sensor fusion at 200 samples a sec. is available from Sparkfun for $16.95, it includes the new emerging 5mm Qwiic I2C connector standard for those who hate to solder. This tiny JST-SH connector format might be useful in compact Pi Compute Module 4 Zynthian host board designs.
QT Py and ICM-20948
The tiny Seedstudio XIAO shown in some experiments above “the world’s smallest microcomputer” that lists for $4.90 has a better competitor (both selling for $5.99 at a local dealer) > The Adafruit QT Py, it’s a pin for pin compatible design with some advantages:

  • Reset button
  • Qwiic compatible I2C connector
  • And a Flash expansion solder pad on the bottom allowing one to add 2Mb of flash, this promotes it to the Adafruit “Express” class allowing the whole compiled circuitpython device driver lib. to be stored on board.
    . (Adafruit has been remaking some old 8 bit processor boards with the 32 bit SAMD21 processor, (Cortex®-M0+ 32bit 48MHz , 256KB Flash, 32KB SRAM) allowing old C++ applications to run in Python with similar speed, the board mounts like a drive volume, allowing code to be edited with a standard PC text editor)
    There’s a passing mention of the I2S interface on the QT Py, allowing a single audio data stream input or output. (This might suffice for adding note detection to a breath controller, picking up a Kazoo hum with a digital mic.)

The “time of flight” rangefinders remind me a bit of a smart gesture sensor chip (with an IR light, 90x90 cam and dsp) recognizes a few gestures. Not suitable for timing critical stuff it’s more of a control panel thing, I believe the rotation sensing can count revolutions (it contains some 80 registers)
It’s plugged into a BBC microbit, that little board they gave every 12 year old in England as a learning aid. The $10-15 board has bluetooth and an accelerometer and galvanometer.

A tiny (65x25x15mm) all in one computer good for a Bluetooth/WiFi controller w/ IMU. The M5stick

It’s a pretty good value, you can find original M5stickCs for $10-$15, ($15.50 Plus model Amazon FBA) the well known bargain ESP32 processor is at the heart, while it doesn’t have native USB-MIDI like some other processors, the wireless options more than make up for it. You can get a watch band to make a poor man’s AppleWatch for minor on stage remote controlling.
The short life tiny battery is sort of a joke, only 2 user buttons, IO Pins are limited, though there is a family of add-on block modules. the upgraded M5stickC Plus has a bigger battery and slightly bigger display. It has a Grove I2C connector, which is pin to pin compatible with the mini Qwiic connector, with an adapter cable.

  • ESP32-based support BLE 4.2 and WiFi
  • Built-in 6-Axis IMU
  • Red LED
  • IR transmitter
  • Microphone
  • RTC
  • Buttons, LCD(1.14 inch)
  • Built-in Lipo Battery
  • Extendable Socket
  • Built-in Passive Buzzer
  • Wearable & Wall mounted
  • Development Platforms: UIFlow, MicroPython, Arduino

I don’t think this is midi


Really cool!! As some of you probably know, I love kalimbas :heart_eyes:

Jofemodo used has electro-Kalimba to test the Audio Injector input back in 2017.

This electro kalimba project has a Teensy in it … so it could do midi over USB :>


I keep meaning to get back to working on an idea that I had where I’d take the load cell from a cheap digital pocket scale, a HX711, and a microcontroller, and build an expression pedal that would pretty much have no moving parts, but it has been pushed so far down the to-do list.
Along the same lines, I thought it could be fun to take an old Wii Fit Balance Board and make a sort of 2 dimensional expression pedal, since it has essentially a load cell on each of the four corners. Think of it as the giant piano from the movie “Big” meets a Korg Kaossilator:)

I just received some HX711 in the mail today, costing about $1 each, apparently some real pedals will stay where you position them, displacement is one of the feedback mechanisms, a solid block with strain gauge might not be as good as some added elastic that compresses.

Not a controller either but an interesting experiment for ambient. Beautifully made. For a starter I used a simple reverb tank and a Donner EQ Seeker equalizer pedal to get the same for a tenth of the price.


Really nice :+1:

Noticed a combination electro Kalimba Theramin(?) combo in this Roli promo photo. Does anyone recognise the project (laser cut box with 4 tines near the Roli Lighpad Block) or any of the other projects?

The search engines don’t know that image.
I did see a couple of other odd Kalimba concepts

The Marimbalite (in 120 years of electronic music)
shares a light theme with the LazerHarp
that rozhok posted in the Success section.

One more wacky instrument from a site that seems to sell oddball effect pedals and instruments.
The Phone-Home Electric Xylophone-trimmed
The Phone-Home Electric Xylophone $240
(Not on par with the new Electric Kalimba)
demo vid . . . . . . . user vid
Their (114) Gadgets . . . . and (76) alternate controllers for sale.

Another project I just ran across, a student xylophone, modified for BLE remote control with a $20 bluetooth board, 6 driver chips and 30 solenoids.
Robo Xylophone

1 Like

Well, THAT was quite an adventure! When I saw this post, my curiosity went to 11, too. Don’t ask me to explain how I tracked it down, but apparently, it’s a LeafAudio Microphonic Soundbox.
Here’s all the details plus a video -

Spoiler alert: No theremin bits. Think: Hainbach scoring a slow-burn horror film.


Good Find!

I’ll have to get myself a violin bow…

The power of google is strong in this one!

I think the element of musical curiosity and adventure is what makes this community a bit unique. Thanks a heap. I like the rabbit holes that Zynthian leads me down :wink: The more I look at what I thought was a generic promo pic for Roli Lumi … the more I want to know what everything is on that desk :stuck_out_tongue_winking_eye:

A Better Look at the Pipe Guy’s Rig.

Pipe Guy Rig
One of his more dynamic videos was previously shown in Music is the Best, this POV video gives a better look at the 15 note player end of one of the more successful simplified instruments. (There are 27 videos in his channel)

To identify the scale used, I had the last 32 seconds of that other video: Pipe Guy - House/Trance/Techno Live - YouTube examined by pYin ‘Notes’ analysis in Sonic Visualizer:

The red boxes are identified notes, they are voiced by Sonic Visualizer’s synth,
it reported these notes:
C2, C2, E2, E3, E3, F2, F2, F2, A2, F2, D2, G2, G2, E2, B3, B3, E3, E3, E3, E3, F2, F2, F2, A2, F2, A2, F2, G2, B3, B3, C2, C2, E2, C2, C2, E3, E3, F2, F2, F2, F2, F2, (4 note Detection error A#3, B3, B3, B3, followed by low volume passage not detected)
The Distinct Ending passage:
D3, E3, C3, C2, D2, D2, B3, C3, B2, F2, E2, D2, C2 (very last Low note undetected Perhaps B2)
I haven’t had a chance to put them in a sequencer to verify the transcription.

1 Like

Love it