SoundWatcher

Audio activity monitoring tool for Windows (WASAPI/ASIO) with HTTP notification support and Home Assistant MQTT integration.

Features

• ✅ Monitor WASAPI devices (Windows Audio Session API) - standard Windows audio devices
• ✅ Monitor ASIO devices - professional low-latency audio interfaces
  • ASIO devices can be detected through input monitoring - the application uses silent capture to activate audio metering
• ✅ Monitor multiple devices simultaneously
• ✅ Send HTTP requests when audio starts (ON) and stops (OFF)
• ✅ Configurable delay before sending OFF signal
• ✅ Real-time peak level monitoring for LED control
  • Peak values are smoothed by sampling every 10ms and sending averaged values
• ✅ Home Assistant MQTT Discovery integration
  • Binary sensor with device class "sound"
  • Automatic discovery - no manual configuration needed
• ✅ System tray icon with context menu
• ✅ Pause/resume monitoring
• ✅ Modern settings interface with tabs
• ✅ Configurable audio detection threshold to filter background noise

Use Case

I use SoundWatcher to automatically power on my Yamaha HS-80 studio monitors only when needed:

This works by sending HTTP requests to a Sonoff switch running Tasmota firmware:

As a bonus, an LED strip controlled by Tasmota pulses to the music:

Requirements

Runtime

• Windows 10 or newer
• .NET 8 Runtime (Desktop) - https://dotnet.microsoft.com/download/dotnet/8.0

Building

One of the following:

1. .NET 8 SDK - https://dotnet.microsoft.com/download/dotnet/8.0 (Recommended)
2. Build Tools for Visual Studio 2022 with ".NET desktop build tools" component

Don't have .NET 8 SDK? Run download-sdk.bat - it will open the download page.

Full installation instructions: INSTALL_SDK.md

Building

Quick Start (Recommended)

build.bat

The script will automatically detect available build tools (.NET SDK or MSBuild).

Single-File EXE (Recommended for Distribution)

Create a single EXE file with all libraries:

publish-single-file.bat

Output: bin\Release\net8.0-windows\win-x64\publish\SoundWatcher.exe

• Size: ~950 KB
• Portable: Single EXE file, icon embedded, no dependencies
• No PDB: Debug symbols excluded from release build
• Requires: .NET 8 Runtime installed on the system

Standalone EXE (Fully Self-Contained)

Create an EXE file with embedded .NET runtime (works without .NET installation):

publish-standalone.bat

• Size: ~70-80 MB
• Requires: Nothing - works immediately

Alternative Methods

Using .NET SDK directly:

dotnet build -c Release

Single-file publish manually:

dotnet publish -c Release -r win-x64 --self-contained false -p:PublishSingleFile=true

Manually using MSBuild (requires VS 2022 Build Tools):

msbuild SoundWatcher.csproj /p:Configuration=Release /restore

Installation

After Standard Build (build.bat)

Executable is located at:

bin\Release\net8.0-windows\SoundWatcher.exe

Copy the entire net8.0-windows directory to your desired location.

After Publish (single-file)

Executable is located at:

bin\Release\net8.0-windows\win-x64\publish\SoundWatcher.exe

Copy only the SoundWatcher.exe file to your desired location - no other files needed.

Usage

1. Run SoundWatcher.exe
2. Icon will appear in the system tray
3. Right-click the icon → Settings
4. Configure:
   • Audio Devices: Check the devices you want to monitor
   • HTTP Notifications: Enter URLs for ON/OFF notifications
   • Timing Settings: Set check interval and OFF delay
   • Home Assistant: Configure MQTT connection (optional)
5. Click Save

Running with Logs (Debugging)

To see real-time logs:

cd "d:\dev\soundwatcher"
dotnet run

Or run the compiled exe from terminal:

cd "d:\dev\soundwatcher\bin\Debug\net8.0-windows"
.\SoundWatcher.exe

Logs are also saved to:

%APPDATA%\SoundWatcher\soundwatcher.log

System Tray Context Menu

• Turn ON - Manually send ON notifications
• Turn OFF - Manually send OFF notifications
• Pause Monitoring - Pause/resume monitoring (icon shows white pause overlay when paused)
• Settings - Open settings window
• Exit - Close application

Configuration

Settings are saved to:

%APPDATA%\SoundWatcher\settings.json

Example Configuration

{
  "OnUrls": [
    "http://192.168.1.10/cm?cmnd=Power%20ON",
    "http://192.168.1.20/webhook/audio-started"
  ],
  "OffUrls": [
    "http://192.168.1.10/cm?cmnd=Power%20OFF",
    "http://192.168.1.20/webhook/audio-stopped"
  ],
  "OnUrlsEnabled": true,
  "OffUrlsEnabled": true,
  "VolumeUrl": "http://192.168.1.30/?m=1&d0={VOL}",
  "VolumeUrlEnabled": true,
  "VolumeUpdateIntervalMs": 120,
  "CheckIntervalMs": 1000,
  "TurnOffDelayMs": 30000,
  "AudioThreshold": 2.0,
  "MonitoredDeviceIds": [
    "{0.0.0.00000000}.{device-guid}"
  ],
  "MonitoringEnabled": true,
  "MqttEnabled": true,
  "MqttBroker": "192.168.1.100",
  "MqttPort": 1883,
  "MqttUsername": "",
  "MqttPassword": "",
  "MqttDeviceName": "PC Audio Monitor"
}

Peak Level URL for LED Control

The VolumeUrl supports a {VOL} placeholder which is replaced with the current peak level (0-100):

http://192.168.1.219/?m=1&d0={VOL}

This is useful for controlling LED strips or other devices that respond to audio levels.

Performance Optimizations

The application dynamically adjusts its checking interval to minimize CPU usage:

• Audio OFF: Checks every 1000ms (check interval)
• Audio ON without peak monitoring: Checks every 1000ms (check interval)
• Audio ON with peak monitoring: Checks every 120ms (peak update interval)

MQTT state changes are only sent when the state actually changes, not on every check.

Differences from Old Version

Removed

• ❌ Dependency on CSCore.dll
• ❌ Dependency on bass.dll
• ❌ Requirement for Visual Studio to build
• ❌ .NET Framework 4.5.2

Added

• ✅ Direct P/Invoke for WASAPI (no external DLLs for WDM)
• ✅ Input device monitoring via silent capture (enables IAudioMeterInformation)
• ✅ ASIO support (via NAudio.Asio)
• ✅ Multi-device selection
• ✅ .NET 8 (modern, faster, better support)
• ✅ Tabbed settings interface
• ✅ URL testing from settings
• ✅ Better OFF delay management (cancels when audio detected again)
• ✅ Peak smoothing for LED control
• ✅ Configurable audio detection threshold
• ✅ Home Assistant MQTT Discovery integration
• ✅ Enable/disable individual URL groups (ON, OFF, Peak)

Architecture

.
├── Audio/
│   ├── WasapiInterop.cs      # P/Invoke for Windows Core Audio API
│   ├── WasapiMonitor.cs      # WASAPI device monitor
│   ├── AsioMonitor.cs        # ASIO device monitor (NAudio)
│   └── AudioMonitor.cs       # Unified monitor (WASAPI + ASIO)
├── Configuration/
│   └── AppSettings.cs        # Configuration management (JSON)
├── Network/
│   └── HttpNotifier.cs       # HTTP notification sender
├── HomeAssistant/
│   └── HomeAssistantMqtt.cs  # MQTT Discovery integration
├── Logging/
│   └── Logger.cs             # Dual console+file logging
├── UI/
│   └── SettingsForm.cs       # Settings interface
├── Program.cs                # Entry point + system tray
└── Resources/
    └── AppIcon.ico           # Application icon

Troubleshooting

Application doesn't detect ASIO devices

• Make sure ASIO drivers are installed
• Some ASIO drivers require administrator privileges
• ASIO devices can be detected via input monitoring

HTTP requests are not sent

• Check URLs in "HTTP Notifications" tab
• Use "Test ON URLs" / "Test OFF URLs" buttons
• Check firewall/antivirus settings

High CPU usage

• Increase "Check interval" in timing settings (e.g., to 2000ms)
• Disable peak monitoring if not needed

Input devices don't show audio activity

• The application uses silent capture to activate metering
• This works for most devices, but some drivers may not support it

License

This project uses:

• MQTTnet (MIT License) - https://github.com/dotnet/MQTTnet
• NAudio.Asio (MIT License) - https://github.com/naudio/NAudio

Author

AIAC

Rebuilt from .NET Framework 4.5.2 to .NET 8