Open-KeyPrec

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  Open-KeyPrec
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  Open-Sourced Electric Keyboard Percussion Instrument
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<a href="#code">Code</a>&nbsp;&nbsp;
<a href="#build">Build</a>&nbsp;&nbsp;
<a href="#usage">Usage</a>&nbsp;&nbsp;
<a href="#license">License</a>
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## About

Open-KeyPrec is an open-sourced, pressure-sensitive electric keyboard percussion (mallet) MIDI instrument. It has 61 keys, spanning 5 octaves of playing range from C2 to C7 like a standard Marimba. It also has a MIDI control panel with 16 buttons, 12 knobs (8 × 280° potentiometers and 4 × 360° rotary encoders).

The sensors are controlled by a development board, and the output is converted into a standard MIDI device. You can use audio workstation softwares like GarageBand or Reaper (or open-source alternatives like LMMS, Zrythm, or Ardour) to simulate the sounds of all kinds of different instruments.

## Code

**Source code structure**

* `/src` - PC driver written in Rust
* `/firmware` - Development board firmware written in C++
* `/circuits` - Printed circuit boards
* `/models` - 3D-printable models

**Toolchains & Environments Used**

* EasyEDA: Web-editor for creating circuit boards
* FreeCAD: Software for designing mechanical 3D models
* CLion: IDE for Rust & C++
* PlatformIO: Firmware development toolkit

**Pin Configuration**

| Pins | I/O | Description                               |
|------|-----|-------------------------------------------|
| 4    | O   | Mux Select for C2-B6                      |
| 5    | IA  | Mux Input for C2-B6                       |
| 1    | IA  | Input for C7                              |
| 8    | I   | (Panel) Input for 4 rotary encoders       |
| 3    | O   | Mux Select for buttons and potentiometers |
| 2    | I   | Mux Input for buttons                     |
| 1    | IA  | Mux Input for potentiometers              |
| 3    | O   | RGB LED Control                           |

Total ADC channels required: 7
Total GPIO required: 23

## Build

### Materials Required

!!!!!!!!!! TODO !!!!!!!!!!

### Tools Required

* FDM 3D Printer (~$300 Ender 3 is fine)
* Soldering kit (iron, solder, flux)
* Wood Saw
* A computer

### 1. Order PCBs

!!!!!!!!!! TODO !!!!!!!!!!

## Usage

### Flash Firmware

1. Install PlatformIO Core ([Guide](https://platformio.org/install/cli))
2. Open the `firmware` directory
3. In your preferred IDE, edit `src/config.h` with your pin configuration.
4. Edit `platformio.ini` to match your dev board.
5. Connect dev board, build and upload firmware using `platformio run --target upload`

### Setup MIDI Device

!!!!!!!!!! TODO !!!!!!!!!!

### Setup Audio Softwares

A MIDI keyboard doesn't make sound on its own. To actually play an instrument, you would need an audio workstation software and some VST sound sources.

Notation: 🍎 - macOS, 🪟 - Windows, 🐧 - Linux

#### Free Mallet Sound Sources

**Built-in Sources**

* GarageBand comes with marimba, vibraphone, and glockenspiel sound sources. It's free but macOS only and does not have VST support.
* LMMS comes with several mallet instruments.

**External Plugins**

| Name & Link | Author | Platforms | Formats |
| --- | --- | --- | --- |
| [Alto Glockenspiel](https://www.steinberg.net/vst-instruments/alto-glockenspiel/) | Steinberg | 🍎 🪟 | VST, AU |
| [Marimbaphonic](http://www.alanvista.com/marimbaphonic/) | Alan Vista | 🍎 🪟 | VST, AU |
| [VibroMaster](http://www.alanvista.com/vibromaster/) | Alan Vista | 🍎 🪟 | VST, AU |
| [DSK Virtuoso](https://www.dskmusic.com/dsk-virtuoso/) (Celesta, Glockenspiel, ...) | DSK Music | 🪟 | VST |

Unfortunately there aren't any free VSTs supporting linux that I can find. You have to use Windows for this one if you don't have a mac/hackintosh. If you found any additional VSTs, feel free to make a PR!

Other free VST Plugins: https://github.com/webprofusion/OpenAudio