Configure and monitor Sketchatone in real-time with the web interface

Web Dashboard

The Sketchatone web dashboard provides a visual interface for configuring and monitoring your tablet in real-time. Changes made in the dashboard take effect immediately without restarting the application.

Accessing the Dashboard

macOS App

The macOS app automatically opens the dashboard in your browser when launched.

Default URL: http://localhost:8080

From Source (Development)

Start the server:

# Node.js
npm run server

# Python
python -m sketchatone.cli.server

Then open your browser to http://localhost:8080

Raspberry Pi / Zynthian

If you've enabled the web server in your config:

{
  "server": {
    "http_port": 8080,
    "ws_port": 8081
  }
}

Access from another device on your network: http://<pi-hostname>:8080

Note: For minimal resource usage, you can disable the dashboard by setting ports to null.

Dashboard Features

1. Live Tablet Monitoring

Live tablet input visualization showing pen position, pressure, tilt, and button states

The dashboard displays real-time tablet input:

Pen position (X/Y coordinates)
Pressure level
Tilt angles (X/Y)
Button states
Strum events

This helps you understand how your tablet movements translate to MIDI output.

2. Strumming Configuration

Strumming configuration panel with chord selection and settings

Configure core strumming settings:

Chord Selection - Choose from preset chords or enter custom notation
MIDI Channel - Set output channel (0-15 or omni)
Pressure Threshold - Adjust sensitivity
Note Spread - Control octave range
Invert X - Flip for left-handed use

Changes apply immediately as you strum.

3. Parameter Mappings

Parameter mapping controls for velocity, duration, and pitch bend

Map tablet inputs to musical parameters:

Note Velocity

Control source (pressure, tilt, position, etc.)
Min/max range
Response curve
Spread type

Note Duration

Control source
Duration range (seconds)
Response curve

Pitch Bend

Control source
Bend range
Response curve
Central/direct/inverse spread

Live Preview: Adjust sliders and immediately hear the effect on your playing.

4. Action Rules (Button Configuration)

Action rules configuration interface showing button mappings

Configure stylus and tablet buttons:

Visual Button Mapping - See which buttons are available
Action Assignment - Drag-and-drop or select actions
Trigger Types - Choose press, release, or hold
Button Groups - Create chord progression groups
Startup Rules - Set initial state

5. Strum Release

Strum release configuration panel

Configure drum sounds on pen lift:

Enable/disable
MIDI note selection
Max duration threshold
Velocity multiplier

6. MIDI Configuration

Note: MIDI configuration (output/input ports, backend selection) is not available in the dashboard as it requires a restart to apply. Configure MIDI settings via JSON files or command-line arguments.

MIDI Settings (Requires Restart):

Output Port (midi_output_id) - MIDI device to send notes to
Input Port (midi_input_id) - MIDI keyboard for chord input
Backend (midi_output_backend) - rtmidi (default) or jack (Linux)
Inter-Message Delay (midiInterMessageDelay) - Prevent stuck notes on slow hardware (e.g., 0.08 for Raspberry Pi)
JACK Settings - Client name and auto-connect mode

To change MIDI settings:

Via JSON file - Edit config.json and restart:

{
  "midi": {
    "midi_output_backend": "rtmidi",
    "midi_output_id": 2,
    "midi_input_id": null,
    "midiInterMessageDelay": 0.08
  }
}

Via command-line arguments:

# Node.js
npm run server -- --midi-port 2

# Python
python -m sketchatone.cli.server --midi-port 2

See Configuration for complete MIDI configuration reference.

Configuration Presets

Loading Configurations

Configuration load/save interface

The dashboard allows you to load different JSON configuration files:

Click "Load Configuration"
Select a JSON file from your computer
Configuration applies immediately

Use Cases:

Switch between songs with different settings
Load performance presets
Test different configurations quickly

Saving Configurations

Save your current dashboard settings to a JSON file:

Configure settings in the dashboard
Click "Export Configuration"
Save the JSON file
Use it later or commit to version control

Creating Presets

Create multiple configuration files for different scenarios:

Example Presets:

ballad.json - Slow, expressive settings with wide pitch bend
rock.json - Fast, aggressive settings with minimal bend
jazz.json - Complex chords with note repeater
drums.json - Strum release enabled for percussive hits

Switch between them instantly in the dashboard without restarting.

Live Performance Features

Real-Time Adjustments

During performance, you can adjust:

Chord changes (via buttons or dashboard)
Transpose on/off (via buttons)
Note repeater on/off (via buttons)
Parameter sensitivity (via dashboard)

Visual Feedback

The dashboard shows:

Current chord being played
Active transpose/repeater state
MIDI messages being sent
Button press events
Tablet input values

This helps you troubleshoot issues during soundcheck or performance.

Headless Mode (No Dashboard)

For production use on Raspberry Pi or Zynthian, you can disable the dashboard entirely:

{
  "server": {
    "http_port": null,
    "ws_port": null
  }
}

This minimizes resource usage. All configuration must be done via JSON files.

Troubleshooting

Dashboard Won't Load

Check server is running:

# Look for "HTTP server listening on port 8080"

Check firewall settings:

macOS: Allow incoming connections for the app
Linux: Ensure port 8080 is not blocked

Changes Don't Apply

Refresh the page:

The dashboard maintains a WebSocket connection
If disconnected, refresh to reconnect

Check console for errors:

Open browser developer tools (F12)
Look for WebSocket connection errors

Can't See Tablet Input

Verify tablet is connected:

Check USB connection
Look for device detection messages in server logs

Check device config:

Ensure your tablet has a matching config file
See Configuration for details

Sketchatone

Turn your drawing tablet into a MIDI strumming controller