This github repository describes and contains the source code and other materials for a 3D printed, teensy 3.6 based MIDI controller. The controller has a 5x5 array of switches, each with an individually adressable ws2812B colored LED, four rotary controllers, a 3.5" touchscreen, inputs for four (4) standard 1/4" expression pedals, a 1/8" stereo jack used for a serial port, and the main USB type "A" connector, a USB host port, and, lol, a volt/amp meter to monitor the USB power supply.
four rotary controllers
3.5" touchscreen
inputs for four (4) standard 1/4" expression pedals, 1/8" stereo jack for serial port, and the main USB type "A" connector
USB host port, and volt/amp meter on USB power supply
It is intended to be a foot controller ... hence the tiered setup which makes it easier to press buttons with your toes without having to reach over other buttons. FWIW, I play the guitar barefooted, while sitting in a chair.
There are two major aspects to this project. First there is the hardware, which is relatively straight forward, and there are circuit diagrams, fusion 360 files, some instructions, and so on that might allow someone to create a copy if they wanted to.
The second major aspect is the software. Inasmuch as this was conceived as BOTH an experimental platform to let me mess with USB midi, and particularly the Fishman FTP Triple Play dongle/controller, it also has been programmed to fit into my existing performance setup. For me, it is "gig ready", as well as a place I can try different experiments with various things.
The software does not present itself as a general purpose, commercially viable, consumer product. Though that could be done, it is not my primary focus. So, while I would be able to create, for example, a box on which the end user could map the buttons to various MIDI CC control messages at "run time", that is not currently implemented.
Because the entire thing can be (fairly) easily programmed from the Arduino IDE, at this time I am selfishly doing whatever the heck I want in C++. Some stuff has been modularized and incorporated into things like a system configuration "preferences" page, with persistent values stored in EEPROM, other stuff is "hard coded" into the C++, an approach which limits the use of this by less technically saavy "consumer" or "nubie" readers and potential users.
That's what it is.
There is still, in my opinion, considerable value in making this public, and so, here, in spite of ongoing development, I am creating a public github repository so that I can present it to you.
TODO: rework this whole section
This repository contains the C++ source code, including the main INO file (teensyExpression.ino) and the C++ and H files needed to build the program.
There are a number of other sub-folders which are considered "private" for my own personal use, and/or which exist only to support the readme.md files in the this and the above subfolders:
- images - contains images used on this and various readme pages
- junk - contains a variety of weird files, images, doc files, that, for me, pertain to the design of the project, but which are not meant to be necessrily useful for a reader or anyone besides myself.
- tests - contains a number of test programs that are not necessarily currently up-to-date or useful. I keep these for posterities sake as they may have snippets of code I will need in the future.
There is a separate repository containing the Fusion 360, STL, and gcode files for this project that were used to 3D print the box and buttons.
TODO: rework
This teensyExpression pedal is intimately involved with my long term ongoing rPi bare metal vGuitar rig project at hackaday.
In that process I have developed a number of other repositories which might be of interest to audio system development hackers, including:
- circle - my fork of a a C++ bare metal rPi development framework
- circle-prh - my extensions to Circle, including a port of the Teensy Audio Library to rPi bare metal, and an Arduino like development approach.
- Loooper - a bare metal rPi based Audio Looper including a 3D printed case with a 7" touchscreen, which hooks up to, and is controlled by, this teensyExpression pedal.
This project relies on the teensyDuino installation.
It also depends on a number of Arduino libraries that must be manually placed in your Arduino/libraries folder. There is one small library that I wrote (myDebug.h and myDebug.cpp), that I generally use in my Arduino programs, and is common to more than one of my published projects.
In addition there are several libraries that are publicly available, but unchanged by me (ILI9341_t3 and ILI9341_fonts), which I have forked into my github account for ease in finding them, and to provide me with a stable known "snapshot" of those libraries.
And finally there are some libraries that are publicly available, but to which I have made modifications to, small or large, in order to get them to work in this project (Paul's USBHost_t36 and my_LCDWIKI_*).
Each of these libraries is available as a github project here in my account, with a name that is formatted like "Arduino-libraries-NameOfLibrary". These libraries should be "cloned" or otherwise copied into your Arduino/libraries folder. Once you have done that, you may rename them to remove the "Arduino-libraries" portion, just leaving the NameOfLibrary portion in the directory structure if you wish.
- myDebug - A debugging output library common to my Arduino projects, it contains global methods with names like "display" and "display_bytes" which are called throughout my code, and which can be turned on or off via defines.
TODO: cleanup NEEDS vs USES forked libraries
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base64 - UNMODIFIED fork of Adam Rudd's https://github.com/adamvr/arduino-base64 repository
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ILI9341_t3 and ILI9341_fonts - These are UNMODIFIED versions of Paul's ILI9341 libraries, forked from his repository on 2020-10-03. My program may compile and work with more current versions that he makes available at https://github.com/PaulStoffregen/ILI9341_t3 and https://github.com/PaulStoffregen/ILI9341_fonts, but these forks are known to compile and work properly with my code.
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USBHost_t36 - A slightly MODIFIED version of Paul's USBHost_t36 library, forked from https://github.com/PaulStoffregen/USBHost_t36 on 2020-10-03. The API was changed to make a few functions virtual and to expose a few private variables as "protected".
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SdFat - A fork of Bill Greiman's https://github.com/greiman/SdFat with one slight modification - to increase BUSY_TIMEOUT_MICROS from 500000 to 1000000, which fixed problems I was having opening an SD card on a fresh boot.
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my_LCDWIKI_GUI, my_LCDWIKI_KBV, and my_LCDWIKI_TouchScreen - These repositories contain the rude and crude port of the LCDWIKI Arduino libraries to the Teensy for the cheap touch screen I ended up using. The touch screen is an 8 bit parellel port screen that looks like this:
When I started working on this project, I started off using a different, much faster and more teensy compatible 2.8" SPI touch screen. One night I burned it, and because I did not want to wait 6 weeks for a replacement (I live on a remote island in the tropics) I was forced to go to a slower speed 8 bit parallel Arduino touch screen ... which in turn required me to port the LCDWIKI library for it to the teensy 3.6, which I did.
Pretty much everything I do has been tremendously influenced by, and is more or less a direct result of the work done by Paul Stoffregen and his wonderful teensy series of MPU boards.
Please visit his website at prjc.com and support him by purchasing teensy boards and teensy related parts and accessories. He also has github, hackaday, and facebook pages that you can find easily on the internet. The man's a giant to me, and has forged important new ground not only with the boards he makes, but also with the vast amount of open source software he has created, not the least of which includes the ws2812 and ili9431 libraries, but also his audio library, and well, what can you say ... so much more!
Also thanks to the many folks who have contributed to the lcdwiki project. Though I can't name them by name, many are the times when I have visited their website and utilized their code.
That's it!
Thanks for checking this out!
Updated October 2020 - Patrick