ART–HAL Demo (Android Studio project)

This minimal app demonstrates how your code running in Android Runtime (ART) talks to hardware indirectly via the Android Framework → System Services → HAL → Linux kernel pipeline.

Features

The app demonstrates 4 key hardware interactions through Android's HAL (Hardware Abstraction Layer):

🔦 Toggle Flashlight

• Turns your device's camera flash on/off
• Flow: App → CameraManager.setTorchMode() → CameraService → Camera HAL → Kernel → LED

🎤 Audio Capture (RMS meter)

• Records audio and shows real-time sound level measurements
• Flow: App → AudioRecord → AudioFlinger → Audio HAL → Kernel → Microphone

📱 Accelerometer Readout

• Displays live accelerometer sensor data (x, y, z coordinates)
• Flow: App → SensorManager → SensorService → Sensors HAL → Kernel → Sensor

📳 Vibration

• Triggers device vibration motor
• Flow: App → Vibrator/VibratorManager → VibratorService → Vibrator HAL → Kernel → Motor

Each action logs the complete path from your app through Android services to the hardware, helping you understand the Android system architecture.

How to Run

Prerequisites

• Android Studio (latest version)
• Physical Android device (recommended - flashlight and sensors work best on real hardware)
• Android 8.0+ (API 26+) device

Setup Steps

1. Import Project

   • Open Android Studio
   • Select "Open an Existing Project"
   • Navigate to and select the ART_HAL_Demo folder

2. Connect Device

   • Enable Developer Options on your Android device
   • Enable USB Debugging
   • Connect via USB cable

3. Build & Run

   • Click the green "Run" button in Android Studio
   • Select your connected device
   • Wait for the app to install and launch

4. Grant Permissions

   • When prompted, grant Camera and Microphone permissions
   • These are required for flashlight and audio features

Using the App

1. Tap any button to test hardware features
2. Watch the log area at the bottom - it shows the complete system call path
3. Try each feature:
   • "Toggle Flashlight" - turns camera flash on/off
   • "Start Audio Capture" - begins recording and shows audio levels
   • "Stop Audio Capture" - stops recording
   • "Vibrate" - triggers a short vibration
   • Accelerometer data updates automatically

What You'll See

• Real-time logging of each hardware call
• Audio level measurements in dBFS
• Live accelerometer readings (x, y, z values)
• Complete Android system stack visualization

Requirements

• Min SDK: Android 8.0 (API 26)
• Target SDK: Android 14 (API 34)
• Permissions: Camera, Record Audio, Vibrate
• Hardware: Camera flash, microphone, accelerometer (all optional - app handles missing hardware gracefully)