LED Feedback Configuration

Conductor provides rich LED feedback for MIDI controllers with comprehensive support for RGB control (HID devices) and basic on/off control (MIDI devices).

Quick Start

Command-Line Usage

The fastest way to enable LED feedback is via command-line flags:

# Start with reactive velocity feedback (recommended)
cargo run --release 2 --led reactive

# Try different schemes
cargo run --release 2 --led rainbow
cargo run --release 2 --led static
cargo run --release 2 --led off

Available Schemes

Choose from 10 built-in lighting schemes:

off - All LEDs disabled
static - Solid color based on current mode
breathing - Slow 2-second breathing effect
pulse - Fast 500ms pulse
rainbow - Rainbow cycle across pads
wave - Wave pattern animation
sparkle - Random sparkles
reactive - Velocity-based colors (green/yellow/red)
vumeter - VU meter style (bottom-up)
spiral - Spiral pattern animation

Configuration File

Basic Setup

Add LED settings to your config.toml:

[device]
name = "Mikro"
led_feedback = true  # Enable LED control

[led_settings]
scheme = "reactive"  # Default scheme
brightness = 255     # Full brightness (0-255)

Reactive Scheme (Velocity Feedback)

The most commonly used scheme, providing color-coded velocity feedback:

[led_settings]
scheme = "reactive"

[led_settings.reactive]
# Velocity ranges and colors
soft_color = { r = 0, g = 255, b = 0 }      # Green (0-40)
medium_color = { r = 255, g = 255, b = 0 }  # Yellow (41-80)
hard_color = { r = 255, g = 0, b = 0 }      # Red (81-127)

# Fade behavior
fade_duration_ms = 1000  # Wait 1s before fading
fade_steps = 10          # Number of fade steps (smoother = more steps)

Visual Example:

Soft tap → 🟢 Green LED
Medium tap → 🟡 Yellow LED
Hard hit → 🔴 Red LED
After 1 second → Smooth fade to mode color

Mode-Based Colors

Each mode can have its own color scheme:

[[modes]]
name = "Default"
color = "blue"
led_idle_brightness = 20      # Dim when idle
led_active_brightness = 255   # Full when pressed

[[modes]]
name = "Development"
color = "green"
led_idle_brightness = 30
led_active_brightness = 255

[[modes]]
name = "Media"
color = "purple"
led_idle_brightness = 15
led_active_brightness = 200

Supported Colors:

"blue" - (0, 100, 255)
"green" - (0, 255, 0)
"red" - (255, 0, 0)
"purple" - (200, 0, 255)
"yellow" - (255, 255, 0)
"cyan" - (0, 255, 255)
"white" - (255, 255, 255)
Custom: { r = 128, g = 64, b = 200 }

Mode Transition Effects

Add visual effects when switching modes:

[[global_mappings]]
description = "Next Mode with Sweep Effect"
[global_mappings.trigger]
type = "EncoderTurn"
cc = 1
direction = "Clockwise"
[global_mappings.action]
type = "ModeChange"
mode = 1
relative = true
transition_effect = "Sweep"

Transition Effects:

[led_settings.transitions]
enable_effects = true
flash_duration_ms = 150   # Flash effect (white → off → new color)
sweep_delay_ms = 30       # Sweep effect (left-to-right wave)
fadeout_steps = 10        # FadeOut effect (smooth color transition)
spiral_delay_ms = 15      # Spiral effect (center-outward)

Available Effects:

Flash - Quick white flash (150ms) - fast mode switching
Sweep - Left-to-right wave (120ms) - smooth sweep
FadeOut - Fade old to new color (200ms) - smooth transition
Spiral - Center-outward spiral (240ms) - artistic
None - Instant change (0ms) - no animation

Mode Indicator Pads

Dedicate specific pads to show the current mode:

[led_settings]
mode_indicator_pads = [13, 14, 15, 16]  # Bottom row
# Pad 13 = Mode 0 indicator
# Pad 14 = Mode 1 indicator
# Pad 15 = Mode 2 indicator
# Pad 16 = Mode 3 indicator

When in Mode 1, pad 14 will light up in green while others remain dim.

Advanced Configuration

Animation Settings

Fine-tune animation parameters for each scheme:

[led_settings.breathing]
cycle_duration_ms = 2000  # 2-second breathing cycle
min_brightness = 0        # Fully off at minimum
max_brightness = 255      # Full brightness at peak

[led_settings.rainbow]
speed = 60           # Degrees per second
saturation = 255     # Full saturation
brightness = 255     # Full brightness
hue_spacing = 22.5   # Degrees between pads

[led_settings.sparkle]
spawn_rate_ms = 100  # New sparkle every 100ms
fade_duration_ms = 200  # Sparkle fades in 200ms
max_active = 4       # Max 4 sparkles at once

HID-Specific Settings (Mikro MK3)

[device]
name = "Mikro"
led_feedback = true
use_hid = true  # Force HID mode

[led_settings.hid]
shared_device = true  # Allow NI Controller Editor access
vendor_id = 0x17cc    # Native Instruments
product_id = 0x1700   # Maschine Mikro MK3

MIDI Feedback Settings

For standard MIDI controllers:

[device]
name = "Launchpad Mini"
led_feedback = true

[led_settings.midi]
note_offset = 36  # C1 (MIDI note 36) = Pad 1
channel = 0       # MIDI channel 0-15
on_velocity = 127 # Velocity for "LED on"
off_velocity = 0  # Velocity for "LED off"

Platform-Specific Notes

macOS

HID devices require Input Monitoring permission:

Open System Settings → Privacy & Security
Select “Input Monitoring”
Enable permission for Terminal or your IDE

Shared device mode:

[led_settings.hid]
shared_device = true  # Works alongside NI Controller Editor

Linux

HID devices may require udev rules:

# Create udev rule for Mikro MK3
sudo nano /etc/udev/rules.d/99-maschine-mikro-mk3.rules

# Add this line:
SUBSYSTEM=="usb", ATTRS{idVendor}=="17cc", ATTRS{idProduct}=="1700", MODE="0666"

# Reload rules
sudo udevadm control --reload-rules
sudo udevadm trigger

Windows

HID devices work out of the box, but may require:

Native Instruments drivers installed
USB device permissions (Windows 10+)

Use Cases

Performance/Live Use

[led_settings]
scheme = "reactive"  # Immediate velocity feedback
brightness = 255     # Full brightness for stage visibility

Studio/Production

[led_settings]
scheme = "static"    # Subtle, non-distracting
brightness = 50      # Dim for low-light studio

Creative/Visual

[led_settings]
scheme = "rainbow"   # Eye-catching animations
brightness = 200     # Bright but not overwhelming

Focused Work

[led_settings]
scheme = "off"       # No distractions

Troubleshooting

LEDs Not Responding

Check device connection:

DEBUG=1 cargo run --release 2 --led reactive
# Look for: "✓ Connected to Mikro MK3 LED interface"

Verify permissions (macOS HID):
- System Settings → Privacy → Input Monitoring

Try MIDI fallback:

[device]
led_feedback = true
use_hid = false  # Force MIDI mode

Wrong Colors

Issue: Colors don’t match expected RGB values
Cause: LED manufacturing variance (±10%)
Solution: Normal behavior, slight color variations expected

Flickering

Issue: LEDs flicker or strobe
Cause: Update rate too high or USB bandwidth saturation
Solution: Use simpler scheme (reactive or static)

Mode Colors Not Showing

Issue: All pads same color regardless of mode
Cause: Using non-mode-aware scheme
Solution: Use static or reactive scheme

Performance Impact

Issue: High CPU usage
Cause: Complex animation scheme
Solution: Switch to reactive or static (<1% CPU)

Examples

Example 1: Simple Reactive Setup

[device]
name = "Mikro"
led_feedback = true

[led_settings]
scheme = "reactive"

[[modes]]
name = "Default"
color = "blue"

[[modes]]
name = "Development"
color = "green"

Example 2: Advanced Multi-Mode with Transitions

[device]
name = "Mikro"
led_feedback = true

[led_settings]
scheme = "reactive"
brightness = 255

[led_settings.transitions]
enable_effects = true
flash_duration_ms = 150

[[modes]]
name = "Default"
color = "blue"
led_idle_brightness = 20
led_active_brightness = 255

[[modes]]
name = "Development"
color = "green"
led_idle_brightness = 30
led_active_brightness = 255

[[modes]]
name = "Media"
color = "purple"
led_idle_brightness = 15
led_active_brightness = 200

[[global_mappings]]
description = "Next Mode with Flash"
[global_mappings.trigger]
type = "EncoderTurn"
cc = 1
direction = "Clockwise"
[global_mappings.action]
type = "ModeChange"
mode = 1
relative = true
transition_effect = "Flash"

Example 3: Studio Mode with Indicators

[device]
name = "Mikro"
led_feedback = true

[led_settings]
scheme = "static"
brightness = 50
mode_indicator_pads = [13, 14, 15, 16]

[[modes]]
name = "Recording"
color = "red"
led_idle_brightness = 10

[[modes]]
name = "Editing"
color = "green"
led_idle_brightness = 10

[[modes]]
name = "Mixing"
color = "blue"
led_idle_brightness = 10

Performance

CPU Usage by Scheme

Scheme	CPU (Idle)	CPU (Active)
off	0%	0%
static	<1%	<1%
reactive	<1%	~1%
breathing	~1%	~1%
rainbow	~2%	~2%
sparkle	~3%	~3%

Memory

Static schemes: <1MB
Animated schemes: <1MB
Per-pad state: ~50 bytes per pad

Update Rate

HID devices: 10fps (100ms per frame)
MIDI devices: Event-driven (no polling)

Conductor Documentation