CamMonitor

Languages: English | 繁體中文 | 日本語
Story: Why I Created This Project: A 40-Year Developer's Reflections on Building with AI

CamMonitor turns your spare Android phone into a private, zero-account home security camera. Connect two Android devices directly using peer-to-peer (P2P) encryption over Wi-Fi or cellular networks without cloud subscriptions, login accounts, or third-party servers storing your video.

---

Key Features

• Zero-Account Setup: No signups, passwords, or cloud accounts. Pairing is completed instantly via an encrypted one-time QR code.
• Strict End-to-End Security: P2P connection encrypted with ECDSA device keys and AES-256-GCM. Only paired devices can access your camera feed.
• Dual Device Roles:
  • Camera Mode: Runs on the phone used as the camera (captures 720p HD video and audio).
  • Viewer Mode: Runs on your daily phone to monitor the live feed.
• Multi-Device Support:
  • 1 Camera can stream to up to 2 viewers simultaneously.
  • 1 Viewer can pair with up to 8 different cameras (e.g., Living Room, Front Door, Baby Nursery).
• Smart Battery & Screen Protection:
  • OLED Black Screen & Touch Guard: Screen turns completely black after 60 seconds of inactivity (or tap the Black Screen button) to prevent OLED burn-in and save power. Releases keep-screen-on while locked, allowing display hardware to sleep and SoC to enter deep suspend. Touch input is locked to prevent stray taps; swipe to unlock.
  • Auto-Standby Mode & Dynamic Wi-Fi: If no viewers are watching for 15 seconds, the camera sensor shuts down and high-performance Wi-Fi lock is released to preserve battery. Both automatically wake when a viewer connects.
  • Hardware Longevity & Anti-Overheating: Deliberately avoids 24/7 continuous video recording and persistent AI object detection to prevent phone overheating, battery swelling, and camera sensor wear. (Users can use AI tools to add these functions if specifically needed).
• Remote Controls from Viewer:
  • 3-Way Night Mode: Switch between Auto (activates via ambient light sensor), Night (forced low-light enhancement), and Normal.
  • Remote Flashlight: Toggle the camera phone's LED torch on and off remotely.
  • Push-to-Talk (PTT) Intercom: Hold the microphone button on the viewer to speak through the camera phone.
  • Orientation & Fit Controls: Rotate incoming video in 90° increments ($0^\circ \to 90^\circ \to 180^\circ \to 270^\circ$) and toggle between Aspect Fit (full uncropped view) and Aspect Fill.
  • Battery Monitoring: View real-time battery percentages and charging statuses for both the camera and viewer devices.
• Automatic Release Detection & Notifications: Periodically checks GitHub Releases via WorkManager (every 24 hours) with zero Google Play dependencies. Sends a system status bar notification when a new version is released even when the app is closed, and renders a convenient update banner card on the Home Screen and About Screen.
• Local Diagnostics: Built-in rolling log viewer with instant share/export for troubleshooting.
• Multi-Language: English, Traditional Chinese (繁體中文), Simplified Chinese (简体中文), and Japanese (日本語).

---

Requirements

• Operating System: Android 9.0 (Pie / API 28) or higher.
• Permissions: Camera, Microphone, and Notifications (Android 13+).
• Network: Both phones must have an active Wi-Fi or mobile data connection. Works on local Wi-Fi (LAN) and over the Internet (WAN).

---

Getting Started

1. One-Time Pairing

Before first use, pair your two devices:

1. On the Camera Phone:
   • Open CamMonitor.
   • Tap Start Camera Mode (or tap Pair Viewer if prompted).
   • A pairing QR code will appear on screen.
2. On the Viewer Phone:
   • Open CamMonitor.
   • Tap Start Viewer Mode (or tap Pair Camera).
   • Point the camera scanner at the QR code displayed on the camera phone.
3. Once scanned, both phones will confirm the pairing automatically.

(You only need to pair once. Paired devices are remembered permanently until manually removed.)

---

2. Using Camera Mode (The Camera Phone)

1. Open CamMonitor and tap Start Camera Mode.
2. Mount or position your phone facing the area you want to monitor.
3. Screen Behavior:
   • HUD Overlay: The top bar shows streaming resolution/FPS (720p 15fps), active viewer count (0/2 in portrait, 0/2 Viewers in landscape), Night mode status, and flashlight status.
   • Screen Behavior & OLED Black Screen: While previewing, the display is kept awake. After 60 seconds without touch (or by tapping the Black Screen button at the bottom left), the screen switches to black screen mode and releases keep-screen-on, allowing the panel to sleep and the SoC to enter deep suspend. Swipe to unlock; the system Back key is ignored while locked.
   • Camera Standby & Dynamic Wi-Fi: If no viewer connects within 15 seconds, the camera enters standby mode and releases high-performance Wi-Fi lock to save battery. It will wake up automatically as soon as a paired viewer connects.
4. To Exit: Tap Exit Camera (or press the Back button and confirm).

---

3. Using Viewer Mode (Your Everyday Phone)

1. Open CamMonitor and tap Start Viewer Mode.
   • If you have multiple cameras paired, a dialog will appear allowing you to select which camera to watch.
2. Live Monitoring Controls:
   • Top Bar:
     • Camera device name and live status badge.
     • Dual battery monitor: displays camera battery level (e.g., Cam 85%⚡) and viewer battery level (Viewer 90%).
     • Night Mode Button: Tap to cycle between Auto, Night, and Normal modes.
     • Torch Button: Tap to turn the camera phone's flashlight on or off.
   • Bottom Bar:
     • Rotate (90°): Rotates the video stream 90 degrees clockwise per tap to adjust for camera mounting angles.
     • Aspect Ratio: Toggle between full view (Aspect Fit) and full screen (Aspect Fill). You can also double-tap the video to toggle.
     • Push-to-Talk (PTT): Press and hold Hold to Talk to broadcast your voice to the camera phone. Release to stop speaking.
     • Audio Mute/Unmute: Toggle camera audio listening on or off.
3. To Exit: Tap the Back arrow at the top-left or use the system back gesture.

---

Managing Paired Devices

• Tap the Devices icon (Icons.Default.Devices) on the top-right of the Home Screen to open Paired Devices.
• View all paired cameras and viewers along with their pairing dates and IDs.
• Tap the red trash icon next to any device to unpair and revoke its access immediately.

---

Language & System Logs

• Change Language: Tap the Globe/Language icon on the top-right of the Home screen to select between System Default, English, 繁體中文, or 日本語.
• System Logs: Tap the Document icon on the top-right of the Home screen to view the connection and signaling diagnostic logs. Tap the Share icon to export the log file.

---

Design Philosophy: Hardware Longevity & Heat Protection

To prevent spare phones from overheating, battery degradation/swelling, and shortened camera sensor lifespan, CamMonitor is deliberately built as an on-demand live monitor rather than a 24/7 continuous recorder:

• No Continuous Video Recording: Keeping the camera sensor and video encoder constantly running generates significant heat and degrades the device and battery quickly.
• No On-Device Object / Motion Detection: Continuous computer vision models require holding the camera sensor and NPU/CPU at high utilization indefinitely.
• Auto-Standby Power Conservation: If no viewer is connected for 15 seconds, the camera hardware shuts down completely and enters low-power standby until a viewer connects.
• Adding These Features: If your specific use case requires continuous recording or object detection, you can use AI coding tools to extend this open-source codebase (e.g. adding CameraX VideoCapture or MLKit object detection onto the existing pipeline).

---

Privacy & Security

• No Video Relaying: Media streams directly peer-to-peer between your phones via WebRTC.
• End-to-End Encryption: Audio, video, and control signals are protected by DTLS-SRTP and AES-GCM encryption.
• Zero Cloud Footprint: No credentials, tokens, or recordings are sent to or stored on any server.

---

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.