FCB1010 Looper Pedal - Project Specification

System Overview

A looper pedal system using a modified Behringer FCB1010 MIDI foot controller, Behringer UMC404HD audio interface, Raspberry Pi with TFT display (215x135mm). The system provides a 5x5 matrix of loop tracks organized in columns and rows, with real-time visual feedback.

Hardware Components

• Behringer FCB1010: MIDI foot controller with 10 footswitches (1-10), UP/DOWN buttons, and 2 expression pedals
• Behringer UMC404HD: Audio interface for input/output
• Single Board Computer: Running Linux
• TFT Display: 215x135mm color display, no touchscreen
• Audio: JACK audio connect kit

System Architecture

Two-State Operation

1. Menu State: Configuration and management functions
2. Performance State: Recording and playback matrix

Matrix Organization

• 5 Columns: Synchronized recording and playback for each column
• 5 Rows: Individual tracks within each column
• 25 Total Cells: Each cell can contain one audio loop
• Column-based Timing: First recording in a column sets the beat count for all tracks in that column

Interface Design

• Metronome: Moving indicator that pulses when in center

• Progress Bars: Show current position in each column with beat divisions

  First recording behavior:

  • Progress bar fills during beat 1, then stays full
  • Additional beats appear as sliding segments (right-to-left)

• Active Row: Increased border with

• Selected Cell: Switched border and background color

• Track States:

  • ---: Empty cell (dark background)
  • READY: Recorded, ready to play (green)
  • PLAY: Currently playing (blue)
  • REC: Currently recording (red)
  • SOLO: Solo mode active (orange/amber)

• Volume Bars: Small bars under each cell showing track volume

Button Mappings

Menu State

• Button 1: Tap Tempo
• Button 2: Enable/Disable Click Track
• Button 3: Not used
• Button 4: Not used
• Button 5: Clear current column
• Buttons 6-10: Column selection (1-5)
• UP/DOWN: Switch to Performance Mode
• Expression Pedal A: Click track volume
• Expression Pedal B: Master volume

Performance State

• Button 1: Record/Arm
• Button 2: Play/Mute current track
• Button 3: Solo current track
• Button 4: Overdub on current track
• Button 5: Clear current track
• Buttons 6-10: Column selection (1-5)
• UP/DOWN: Navigate rows (switch between track rows), return to Menu when at top or bottom
• Expression Pedal A: Current track volume
• Expression Pedal B: Master volume

Operational Behavior

Recording Workflow

• First Recording in Column: Sets beat count for entire column, records until stopped
• Subsequent Recordings: Auto-sync to established column length
• Record Button Stop: Recording stops, cell starts playing
• Stop Button Stop: Recording cancelled, previous state restored
• Overdub Button Stop: Recording continues for next loop, overdubs on previous content

Timing and Synchronization

• All actions sync to the beat: Start/stop occurs at metronome center position
• Column Switching: Only when not recording, immediate switching to selected column
• Tempo Changes: Only allowed when all tracks are cleared
• Recording Start: Synced to column start if column playing, otherwise next beat

Solo Functionality

• Solo Activation: Press Solo button on any track
• Solo Indication: Cell shows SOLO state in orange/amber color
• Multiple Solo: Additional tracks can be added to solo group
• Solo Play: Activates solo tracks + any tracks showing PLAY state
• Solo Stop: Stops entire column
• All Solo Actions: Synced to next beat

MIDI Implementation

• Startup: Send SysEx configuration to FCB1010 for proper button/pedal mapping
• Expression Pedals: Set volume on change
• MIDI Feedback: Send click track to sync with other systems

State Management

• Startup Behavior: Load last audio tracks and configure FCB1010
• Column Consistency: Recordings automatically match column beat count
• State Validation: Prevent invalid operations (e.g., switching columns while recording)