Hykilpikonna
130 lines
5.2 KiB
Markdown
130 lines
5.2 KiB
Markdown
<h1 align="center">
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Open-KeyPrec
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<h4 align="center">
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Open-Sourced Electric Keyboard Percussion Instrument
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</h4>
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<h5 align="center">
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<a href="#code">Code</a>
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<a href="#build">Build</a>
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<a href="#usage">Usage</a>
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<a href="#license">License</a>
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</h5>
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<br>
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<br>
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</h1>
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## About
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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).
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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.
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## Code
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**Source code structure**
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* `/src` - PC driver written in Rust
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* `/firmware` - Development board firmware written in C++
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* `/circuits` - Printed circuit boards
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* `/models` - 3D-printable models
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**Toolchains & Environments Used**
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* EasyEDA: Web-editor for creating circuit boards
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* FreeCAD: Software for designing mechanical 3D models
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* CLion: IDE for Rust & C++
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* PlatformIO: Firmware development toolkit
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**Pin Configuration**
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| Pins | I/O | Description |
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|------|-----|-------------------------------------------|
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| 4 | O | Mux Select for C2-B6 |
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| 5 | IA | Mux Input for C2-B6 |
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| 1 | IA | Input for C7 |
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| 8 | I | (Panel) Input for 4 rotary encoders |
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| 3 | O | Mux Select for buttons and potentiometers |
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| 2 | I | Mux Input for buttons |
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| 1 | IA | Mux Input for potentiometers |
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| 3 | O | RGB LED Control |
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Total ADC channels required: 7
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Total GPIO required: 23
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## Build
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### Materials Required
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!!!!!!!!!! TODO !!!!!!!!!!
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### Tools Required
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* FDM 3D Printer (~$300 Ender 3 is fine)
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* Soldering kit (iron, solder, flux)
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* Wood Saw
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* A computer
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### 1. Order PCBs
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I ordered my PCBs from JLC, but any PCB service would work. They should accept the exported Gerber zip files in `circuits/Exports` folder.
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I created two circuit boards for this keyboard, one is the multiplexer ([Mux v2.zip](circuits/Mux%20v2.zip)) which uses the CD74HC4067 1:16 multiplexer ic to convert the 61 separate analog inputs requirement into only 5 analog inputs and 4 digital switch outputs.
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It also haso diodes and resistors for voltage protection. The other pcb ([OKP-Panel-SMT.zip](circuits/OKP-Panel-SMT.zip)) is for the MIDI control panel containing the buttons and knobs.
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1. Go to jlcpcb.com (Or jlc.com if you read Chinese)
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2. Upload the Gerber file
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3. Set parameters: FR-4, 2 Layers, Color, leave default for other options
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**PCB Assembly (SMT)**
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If you're not comfortable soldering small SMD components, you can order PCB Assembly from JLC.
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You can also select which parts you would like to SMT based on your soldering abilities.
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For example, in the Mux pcb, I ordered SMT for only the 0603 Zener diodes and the CD74HC4067 ic, and hand-soldered everything else.
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1. Order "PCB Assembly" (SMT) and click confirm
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2. In the SMT menu, upload the BOM and CPL (PickAndPlace) files
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3. After uploading, remove the parts you want to manually solder (they're pretty expensive, since someone in the factory still have to manually solder them for you)
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4. Order manually-soldered parts somewhere else (e.g. szlcsc.com)
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## Usage
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### Flash Firmware
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1. Install PlatformIO Core ([Guide](https://platformio.org/install/cli))
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2. Open the `firmware` directory
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3. In your preferred IDE, edit `src/config.h` with your pin configuration.
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4. Edit `platformio.ini` to match your dev board.
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5. Connect dev board, build and upload firmware using `platformio run --target upload`
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### Setup MIDI Device
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!!!!!!!!!! TODO !!!!!!!!!!
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### Setup Audio Softwares
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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.
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Notation: 🍎 - macOS, 🪟 - Windows, 🐧 - Linux
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#### Free Mallet Sound Sources
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**Built-in Sources**
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* GarageBand comes with marimba, vibraphone, and glockenspiel sound sources. It's free but macOS only and does not have VST support.
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* LMMS comes with several mallet instruments.
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**External Plugins**
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| Name & Link | Author | Platforms | Formats |
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| --- | --- | --- | --- |
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| [Alto Glockenspiel](https://www.steinberg.net/vst-instruments/alto-glockenspiel/) | Steinberg | 🍎 🪟 | VST, AU |
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| [Marimbaphonic](http://www.alanvista.com/marimbaphonic/) | Alan Vista | 🍎 🪟 | VST, AU |
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| [VibroMaster](http://www.alanvista.com/vibromaster/) | Alan Vista | 🍎 🪟 | VST, AU |
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| [DSK Virtuoso](https://www.dskmusic.com/dsk-virtuoso/) (Celesta, Glockenspiel, ...) | DSK Music | 🪟 | VST |
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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!
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Other free VST Plugins: https://github.com/webprofusion/OpenAudio |