DIY for Axe-Fx III Foot Controller

ed515

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For anybody in the DIY community that is interested in building or collaborating with me to build their own foot controller. My prototype boards are working great and I am designing the next stage of my PCB for a DIY foot controller for the AXE III. Anybody that may be interested in a PCB board let me know and I can discuss details and add you to my order. These boards are 95% SMD. I can upload images later.

Specs so far:
2 X SAMD21G18 Micro Conrollers (Arduino based) (one micro is 100% dedicated to reading the footswitches)
SD Card slot(just because)
16 Foot switch inputs
16 NeoPixel 5mm LEDs
Nextion or 4DS serial driven display(touch screen optional)...up to 7"
Up to 3 amps of 5V onboard power(determined by external power supply) for display screen and LED's
9V power input, 5V buck convertor and 3.3v step down; board can also be powered over USB during development process. LCD may need external power. Jumpers available for this.
WinBond SPI Flash 32Mb
Midi In/Midi Out
SPI or I2C will be available for scribble strips but not currently standard due to the number of CS needed(a problem to be solved with a plexor or third micro later if needed)

I am rapidly building out the firmware.
 
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Looks like you're pretty far along, what kind of help are you looking for? Do you have schematics you want to share, I can build a breadboard version work on code for you. Or were you looking for some other type of help? Have you considered an indiegogo or other crowdfunding source?
 
If interest is high enough...I'm thinking kit for now because I do not want to go through the cost of FCC certifications of an assembled unit. I am using a couple PCBs from other project right now with a 3.5 inch LCD, so it is a bit Frankenstein right now. Once I merge the schematics onto a single PCB I can have it manufactured and populate the PCB circuitry and load initial functional firmware. It will require some rudimentary assembly of connecting things into the enclosure, plugging in some harnesses, installing foot switches and either soldering or screw terminal connections for the foot switches.

The communication firmware for all available features on the AXE 3 is just about done. Footswitch decoding is done. The GUI is a work in progress and will be self contained to either the Nextion or 4DS display units. I'm still on the fence about which display to use, I do have both. Nextion has the font issue and 4DS displays which are superior cost $100 more. I'm looking for opinions on whether to go with scribble screens? It's about an additional $5 per 1.8" color screen for that option and much more assembly required. With a 7" display it seems overkill....but then again...isn't overkill the whole reason for DIY?

Estimated total cost for all parts $325 - $425 depending on what LCD display is used.

An additional $80 for scribble strips on all foot switches plus additional PCBs.

Any and all input will be considered and appreciated to get this as close to the dream machine that the AXE III already is!
 
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Will you prefer to writing your own firmware or prefer a working kit with both hardware/software once assembled?

My intent is to have about 4 to 5 screens

  1. Patch list with paging and selection
  2. Scene list and selection after patch selection(mode switch)
  3. Effect list and switching after scene selection(mode switch)
  4. Tuner
  5. Setup screen
 
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It would be nice to have an open source code :)

I wrote a working code, available on my signature. Last thing I was working is an individual display for each pedal switch (to show the scene name or the switch function), but still haven't found time and patience to finish it.
 
My goal is to provide/build a dedicated Foot Controller PCB (and possibly the enclosure) that bridges the gap between the AXE III and open source code in a nice neat package.

Offboard wiring will be limited to:
  • A power switch if wanted
  • The footswitches
  • A 4 wire harness to the LCD display
I will only claim propriatary to the button controller because that is years in the making and is already in other products that I have sold; for that reason it needs to remain propriatery. The button controller output will be exposed to the main micro controller via i2c and or Serial.

I'm also working to have the PCB contain add on plug in modules for internal displays and a mini tactile button layout module to mimic footswitches for those that do not yet have an enclosure to use for testing and debugging.

I will preflash the microcontrollers with SAM-BA booltoaders so the microcontroller can be programmed from aurduino or visual micro platofrms. The main board will have a custom board definition and custom variants for the SERCOM with overrides for 3xSerial ports, 1xSPI and 1xI2C.

USB Serial: Debugging
Serial1: MIDI
Serial 2: Available
Serial 3: Display control for 4DS or Nextion LCD.
SPI: for SD if needed and winbond flash to hold static data/configuration data and possibly scribble screens.
I2C: internal OLED display for debugging, and can also be used for internal communication to second microcontroller(for footswitches and possibly expression pedal)

I've been working with the 32-bit SAMD21 for several years and have built dozens of PCBs for automotive and musical equipment industries with great success, it is a very proven micro-controller.
 
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That enclosure looks awesome. I love the screen too. I thought about scribble strips, but in practice I find I don’t change layouts that often and get used to where things are, so I just use a label machine.
 
How did you build that enclosure? I would be interested in that alone!

The scene querying sysex remains a tightly-guarded secret ☹️ The only published method is to query the current scene. Maybe we could ask cliff nicely to publish this?
 
There is one solution to the scene names I have considered... a function to just cycle through the presets and read all the info to an sd. Then when you switch presets it loads scene names from the card. Unfortunately atm there is no other way to read a scene name without switching to it.
 
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