Project Overview: The DIY MIDI Powerhouse

The Botonera 2000 is a testament to the power of upcycling and amateur engineering. Originally conceived as a prototype to control a Lexicon MPX1 effects rack, it has evolved into a robust, definitive MIDI foot controller. Built almost entirely from recycled electronics and housed in a unique case made from two Betamax video boxes, this project proves that professional-grade musical equipment can be built with an Arduino Uno and some creativity.

Engineering & Upcycling

One of the most impressive aspects of Botonera 2000 is its sustainability. Most components, including the 9V battery clips and various connectors, were salvaged from unused or broken devices.

• Chassis Design: The dual-Betamax case provides surprisingly durability and enough internal volume to house the Arduino Uno, complex wiring looms, and eight heavy-duty foot switches.
• Expression Support: The inclusion of an Audio TRS (Tip-Ring-Sleeve) plug allows an external expression pedal to be connected, converting analog voltage sweeps into MIDI Continuous Controller (CC) messages.
• Physical Feedback: Six LEDs provide immediate visual status of which effects are active or which mode the controller is currently in.

Technical Functionality & firmware Modes

The real magic of Botonera 2000 lies in its custom firmware logic. During the COVID-19 pandemic, the author expanded the code from a simple one-channel setup to a sophisticated multi-mode system.

Mode 1: Classic Performance Mode

In this mode, the controller functions primarily on MIDI Channel 1.

• 6 Main Buttons: Send MIDI CC (Control Change) messages to toggle effects (bypass/active).
• 2 Extra Buttons: Used for global parameters like Tap Tempo or Patch Change.
• 3 Potentiometers: Map to volume, gain, or effect depth on the current channel.

Mode 2: Expanded Setup/Multi-Channel Mode

Activated via a toggle switch, this mode unlocks the full potential of the device:

• Channel Mapping: The 6 main buttons become selectors for MIDI Channels 11 through 16.
• Dynamic Reassignment: When a channel is selected, the physical potentiometers and extra buttons are automatically reassigned to that specific MIDI channel. This effectively multiplies the controller's capacity, transforming 3 physical pots into 18 virtual parameters.

Understanding the MIDI Protocol

The project utilizes the standard MIDI 5-pin DIN output. The Arduino Uno sends serial data at the specific MIDI baud rate of 31,250 bits per second. Each message follows the standard MIDI protocol (Status Byte followed by Data Bytes), ensuring compatibility with any modern effects rack or PC-based Digital Audio Workstation (DAW).

Conclusion

Botonera 2000 is an inspiring project for guitarists and producers. It demonstrates how a basic Arduino setup can be expanded through clever software logic to rival commercial MIDI footswitches that cost hundreds of dollars. For anyone interested in the intersection of music tech and DIY electronics, Botonera 2000 provides a perfect roadmap for building a custom, high-performance controller.