Add physical VU meter hardware support (4 dials)

New features:
- SerialManager for USB/Serial communication with hardware
- Support for 4 physical VU meter dials
- Flexible channel mapping: Audio L/R, Peak, Mono, CPU, RAM, Disk, Network
- Multiple protocols: Raw bytes, Text, JSON, VU-Server compatible
- Per-dial configuration: min/max values, inversion, smoothing
- Hardware panel in main view showing dial status
- Hardware settings sheet for configuration
- Auto-detection of USB serial devices

Protocol formats:
- Raw: [0xAA][D1][D2][D3][D4][0x55]
- Text: CH1:val;CH2:val;CH3:val;CH4:val\n
- JSON: {"dials":[d1,d2,d3,d4]}
- VU-Server: #0:val\n#1:val\n...

AudioVUMeter/README.md

@@ -1,6 +1,6 @@
 # Audio VU Meter for macOS
 
-A native macOS SwiftUI application that displays real-time audio levels from BlackHole (or any audio input device) as a classic VU meter, along with system resource monitoring.
+A native macOS SwiftUI application that displays real-time audio levels from BlackHole (or any audio input device) as a classic VU meter, along with system resource monitoring. **Now with physical VU meter hardware support!**
 
 ![macOS](https://img.shields.io/badge/macOS-13.0+-blue.svg)
 ![Swift](https://img.shields.io/badge/Swift-5.0-orange.svg)
@@ -21,11 +21,26 @@ A native macOS SwiftUI application that displays real-time audio levels from Bla
 - **Disk Activity** - Disk I/O activity indicator
 - **Network Activity** - Network throughput monitoring
 
+### Physical VU Meter Hardware Support
+- **4 Physical Dials** - Support for up to 4 physical VU meter dials
+- **Flexible Channel Mapping** - Assign any metric to any dial:
+  - Audio Left/Right channels
+  - Audio Peak or Mono (L+R)
+  - CPU, RAM, Disk, Network usage
+- **Multiple Serial Protocols**:
+  - Raw Bytes: `[0xAA] [D1] [D2] [D3] [D4] [0x55]`
+  - Text Commands: `CH1:val;CH2:val;CH3:val;CH4:val\n`
+  - JSON: `{"dials":[d1,d2,d3,d4]}`
+  - VU-Server Compatible: `#0:val\n#1:val\n...`
+- **Configurable per dial**: Min/max values, inversion, smoothing
+- **Auto-detection** of USB serial devices
+
 ## Requirements
 
 - macOS 13.0 (Ventura) or later
 - Xcode 15.0 or later (for building)
 - [BlackHole](https://existential.audio/blackhole/) virtual audio driver (recommended)
+- USB/Serial VU meter hardware (optional)
 
 ## Installation
 
@@ -40,7 +55,7 @@ A native macOS SwiftUI application that displays real-time audio levels from Bla
 
 1. Clone the repository
 2. Open `AudioVUMeter.xcodeproj` in Xcode
-3. Build and run (⌘R)
+3. Build and run (Cmd+R)
 
 ```bash
 git clone <repository-url>
@@ -54,16 +69,29 @@ open AudioVUMeter.xcodeproj
 - **Audio Levels**: The vertical VU meters show Left (L) and Right (R) channel audio levels
 - **dB Readings**: Numeric display of current audio levels in decibels
 - **System Meters**: Circular gauges showing CPU, RAM, Disk, and Network usage
+- **Hardware Output**: Shows status of connected physical VU meters
 
 ### Controls
 - **Start/Stop**: Toggle audio capture on/off
 - **Reset**: Clear peak hold indicators
-- **Settings**: Access device selection and preferences
+- **Settings** (gear icon): Access device selection and preferences
+- **Hardware** (cable icon): Configure physical VU meter connection
+
+### Hardware Setup
+
+1. Connect your USB/Serial VU meter hardware
+2. Click the cable icon or go to Settings -> Hardware
+3. Select your serial port from the dropdown
+4. Choose the appropriate baud rate (default: 115200)
+5. Select the communication protocol your hardware uses
+6. Assign channels to each dial (Audio L, R, CPU, RAM, etc.)
+7. Click "Connect"
 
 ### Settings
 - **Input Device**: Select audio input source (BlackHole, microphone, etc.)
 - **Reference Level**: Adjust the 0 dB reference point
 - **Peak Hold Time**: Configure how long peak indicators remain visible
+- **Hardware**: Serial port, protocol, and dial assignments
 
 ## Architecture
 
@@ -74,6 +102,8 @@ AudioVUMeter/
 ├── VUMeterView.swift        # VU meter components
 ├── AudioEngine.swift        # Core Audio capture engine
 ├── SystemMonitor.swift      # System resource monitoring
+├── SerialManager.swift      # USB/Serial communication
+├── HardwareView.swift       # Hardware configuration UI
 ├── SettingsView.swift       # Settings window
 └── Assets.xcassets/         # App icons and colors
 ```
@@ -82,16 +112,45 @@ AudioVUMeter/
 
 - **AudioEngine**: Uses AVAudioEngine to capture audio from the selected input device, calculates RMS levels, and converts to dB
 - **SystemMonitor**: Uses Mach kernel APIs to retrieve CPU, memory, disk, and network statistics
+- **SerialManager**: Handles USB/Serial communication with physical VU meter hardware
 - **VUMeterView**: SwiftUI views for classic vertical VU meters with segment-based display
 - **SystemMeterView**: Circular gauge components for system metrics
 
+## Hardware Protocol Reference
+
+### Raw Bytes Protocol
+```
+Start: 0xAA
+Data:  [Dial1] [Dial2] [Dial3] [Dial4]  (0-255 each)
+End:   0x55
+```
+
+### Text Command Protocol
+```
+CH1:128;CH2:64;CH3:200;CH4:32\n
+```
+
+### JSON Protocol
+```json
+{"dials":[128,64,200,32]}
+```
+
+### VU-Server Compatible Protocol
+```
+#0:50
+#1:75
+#2:30
+#3:90
+```
+Values are percentages (0-100)
+
 ## BlackHole Setup Guide
 
 1. **Install BlackHole**: Download and install from [existential.audio](https://existential.audio/blackhole/)
 
 2. **Create Multi-Output Device**:
-   - Open Audio MIDI Setup (Applications → Utilities)
-   - Click the `+` button → Create Multi-Output Device
+   - Open Audio MIDI Setup (Applications -> Utilities)
+   - Click the `+` button -> Create Multi-Output Device
    - Check both your speakers and BlackHole
    - Set as default output
 
@@ -99,6 +158,13 @@ AudioVUMeter/
    - System audio will now go to both speakers and BlackHole
    - Audio VU Meter captures from BlackHole input
 
+## Compatible Hardware
+
+This app is designed to work with:
+- [VU Dials by Sasa Karanovic](https://github.com/SasaKaranovic/VU-Server)
+- Arduino-based VU meters with serial interface
+- Any USB/Serial device accepting the supported protocols
+
 ## API Reference
 
 ### AudioEngine
@@ -136,6 +202,25 @@ systemMonitor.diskActivity
 systemMonitor.networkActivity
 ```
 
+### SerialManager
+
+```swift
+// Connection
+serialManager.connect()
+serialManager.disconnect()
+
+// Configuration
+serialManager.selectedPortPath = "/dev/cu.usbserial-XXX"
+serialManager.baudRate = 115200
+serialManager.selectedProtocol = .vuServer
+
+// Dial assignment
+serialManager.dialConfigs[0].dialChannel = .audioLeft
+serialManager.dialConfigs[1].dialChannel = .audioRight
+serialManager.dialConfigs[2].dialChannel = .cpu
+serialManager.dialConfigs[3].dialChannel = .ram
+```
+
 ## License
 
 MIT License - See LICENSE file for details.