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@K5SMJ K5SMJ released this 31 Mar 21:02
· 46 commits to main since this release
v1.5.0
1d9ee48

KB1 Firmware v1.1.1 Release Notes

HOTFIX UNDERWAY !

DO NOT select 'ERASE ENTIRE FLASH' for this version if you want to keep your battery level data from being lost. - v1.6 will address this

Overview

Release Date: March 31, 2026

🎯 What's New

Non-Blocking Strum System

  • Monophonic strum behavior - New chord/strum now interrupts previous one
  • Non-blocking cascade - Strum notes play over time without blocking main loop
  • Improved responsiveness - No more delay() calls blocking input processing
  • Consistent behavior - Both chord and strum modes now operate monophonically
  • Immediate interruption - Starting new strum stops previous cascade instantly

Technical Details:

  • Strum notes cascade using time-based state machine (updateStrum)
  • First note plays immediately on key press, subsequent notes scheduled
  • Key release stops all notes from the chord/strum
  • No more blocking delays in hotpath

Voicing Control (Octave Expansion)

  • 1-3 octave voicing - Expand chords across multiple octaves
  • Root-forward voicing - Chord pattern repeats at +12, +24 semitones
  • Up to 15 notes - 5-note chord × 3 octaves = massive polyphonic spread
  • MAX_CHORD_NOTES increased from 4 to 16 to support expanded voicings
  • Configurable via web app - Voicing slider in Chord & Strum settings

Example:

  • Major chord (C-E-G) with voicing=1: plays C4-E4-G4 (3 notes)
  • Major chord (C-E-G) with voicing=2: plays C4-E4-G4-C5-E5-G5 (6 notes)
  • Major chord (C-E-G) with voicing=3: plays C4-E4-G4-C5-E5-G5-C6-E6-G6 (9 notes)

USB State Persistence

  • Deep sleep/wake support - USB connection state persists across sleep cycles
  • Fresh boot detection - Distinguishes fresh power-on from wake-from-sleep
  • Proper charging detection - Bypass mode flag preserved across reboots
  • NVS storage - lastUsbState and usbConnectedAtBoot saved to flash

Impact:

  • Sleep/wake cycles no longer lose bypass mode state
  • Charging detection more reliable after wake
  • Battery monitoring continues correctly after deep sleep

Default Value Tuning

  • Velocity Spread minimum increased from 8% to 10% for better musical range
  • Strum Speed default changed from 30ms to 80ms (moderate-fast)
  • Touch Threshold increased from 24000 to 36800 (20% sensitivity)
  • Touch Minimum lowered to 30000 (from 24000) for better dynamic range

Improved Strum Timing

  • Swing calculation now uses absolute value of strum speed
  • Negative speed = reverse - Strum direction controlled by speed sign
  • Consistent swing behavior regardless of strum direction

🔧 Technical Changes

Architecture

  • Added esp_system.h include for reset reason detection
  • Expanded ChordSettings struct with voicing field
  • Added strum state tracking (_strumActive, _strumInProgress, etc.)
  • Implemented updateStrum() for non-blocking cascade playback

Persistence

  • Battery state saves lastUsbState and usbConnectedAtBoot to NVS
  • Fresh boot clears USB state flags for proper detection
  • Deep sleep wake restores flags from NVS

Code Quality

  • Removed all blocking delay() calls from strum pathcod
  • Time-based state machines for both basic strum and arpeggiator
  • Better separation of concerns (strum vs arpeggiator logic)

📊 Performance Impact

Improved:

  • No blocking delays in input processing (strum now non-blocking)
  • Chord/strum key presses more responsive
  • Main loop runs consistently without interruption

Neutral:

  • Voicing expansion adds minimal CPU overhead (just interval calculation)
  • USB persistence adds <1ms to boot time (NVS read)

🎵 Musical Impact

Voicing Feature:

  • Create lush, rich chord arrangements with 1-3 octave spread
  • Useful for cinematic pads, orchestral arrangements
  • Increases polyphonic chord count up to 15 simultaneous notes

Monophonic Behavior:

  • More predictable for live performance (no overlapping chords)
  • Matches expected behavior of physical instruments
  • Cleaner sound (previous chord stops when new one starts)

🔄 Migration Notes

From v1.4.x:

  • Chord/strum behavior now monophonic (previous chord stops)
  • Velocity spread minimum raised to 10% (was 8%)
  • Strum speed default changed to 80ms (was 30ms)
  • Touch threshold changed to 36800 (was 24000)
  • Existing presets will work but may sound slightly different

Settings Affected:

  • Chord Settings: Added voicing field (defaults to 1)
  • Touch Settings: threshold changed from 24000 to 36800
  • Chord Settings: velocitySpread minimum now 10% (was 8%)
  • Chord Settings: strumSpeed default now 80ms (was 30ms)

📝 Known Limitations

  • Voicing only applies to chord mode (not individual scale notes)
  • Strum pattern direction controlled by speed sign (not separate setting)
  • Maximum 16 simultaneous chord notes (hardware MIDI limit)

🚀 Upgrade Instructions

  1. Flash firmware: Use combined binary KB1-firmware-v1.5.0.bin
  2. Update web app: Rebuild or deploy latest KB1-config
  3. Test functionality: Verify voicing slider in Chord & Strum settings
  4. Adjust defaults: May need to tweak touch threshold or strum speed for your preference

Firmware: v1.5.0
Web App: v1.5.0
Compatibility: ESP32-S3 (Seeed XIAO)
Flash Size: 8MB (max_app_8MB.csv partition scheme)

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