WizDataCollector

A Wear OS app for collecting sensor data from a Galaxy Watch and uploading it directly to Edge Impulse for machine learning model training.

Features

• Select from all available Android sensors on the device (accelerometer, gyroscope, heart rate, magnetometer, barometer, and more)
• Raw PPG (photoplethysmography) via Samsung Health Sensor SDK at 100 Hz — green, IR, and red channels
• Custom label input for each recording session
• Configurable sample duration (2 s – 60 s)
• Direct upload to Edge Impulse ingestion API
• API key stored on-device (never hardcoded)

Tested on: Galaxy Watch 4 Classic (SM-R890) · Wear OS · Android 16 (API 36)

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Prerequisites

Samsung Health Sensor SDK (required for PPG)

The PPG sensor uses the Samsung Health Sensor SDK, which is a proprietary AAR that cannot be included in this repository. You must download it manually from Samsung.

1. Go to developer.samsung.com/health/sensor
2. Sign in with a Samsung developer account (free)
3. Click Download SDK → download samsung-health-sensor-sdk-v1.4.1.zip (or latest)
4. Unzip it — the AAR is at:

   samsung-health-sensor-sdk-v1.4.1/1.4.1/libs/samsung-health-sensor-api-1.4.1.aar
   

5. Copy the AAR into the project:

   app/libs/samsung-health-sensor-api-1.4.1.aar
   

6. The app/build.gradle.kts already references it:

   implementation(files("libs/samsung-health-sensor-api-1.4.1.aar"))

The AAR is gitignored. Without it the project will not compile.

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One-Time Watch Setup

These steps survive reboots and only need to be done once.

1. Enable Developer Options

On the watch:

1. Settings → About → Software
2. Tap Software version 7 times until "Developer mode enabled" appears

2. Enable Wireless Debugging

1. Settings → Developer Options
2. Enable Wireless debugging
3. Tap Wireless debugging to open it — note the IP address and port

3. Enable Samsung Health Platform Developer Mode

This is required for the PPG sensor to work. Without it you will get an SDK_POLICY_ERROR.

On the watch:

1. Settings → Apps → Health Platform
2. Tap the "Health Platform" title text 10 times
3. [Dev mode] appears below the title — setup is complete

Important: The ADB command adb shell settings put global health_platform_developer_mode 1 is NOT sufficient on its own. The UI tap is required to unlock the tracker-level policy check.

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First-Time ADB Setup

Pair and connect

# Pair once (use the pairing IP:port and code shown on the watch)
adb pair 192.168.1.x:XXXXX
# Enter the pairing code when prompted

# Connect (use the main IP:port from the Wireless debugging screen)
adb connect 192.168.1.x:XXXXX

# Verify the watch appears
adb devices

The pairing port is different from the connection port. The connection port changes every session.

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After Every Android Studio Deploy

Permissions reset on each install. Run these three grants every time you deploy:

adb -s <ip:port> shell pm grant com.example.eidatacollector \
  "com.samsung.android.hardware.sensormanager.permission.READ_ADDITIONAL_HEALTH_DATA"

adb -s <ip:port> shell pm grant com.example.eidatacollector \
  android.permission.BODY_SENSORS

adb -s <ip:port> shell pm grant com.example.eidatacollector \
  android.permission.ACTIVITY_RECOGNITION

Why READ_ADDITIONAL_HEALTH_DATA? Android 16 (API 36) changed the permission model for Samsung biometric sensors. BODY_SENSORS alone no longer grants access to the Samsung Health Sensor SDK trackers. The Samsung-specific permission is required in addition to BODY_SENSORS.

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Set Your Edge Impulse API Key

Typing a long key on a watch is impractical — use ADB to paste it directly.

1. Log in to Edge Impulse Studio → your project → Dashboard → Keys
2. Copy the API key (starts with ei_)
3. Open the app → tap ⚙ → tap the API key field to focus it
4. On your computer:

   adb -s <ip:port> shell input text "ei_your_full_api_key_here"

5. Tap SAVE

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Usage

1. Tap SENSORS to select which sensors to record
   • Standard Android sensors are listed by name
   • PPG Sensor (Samsung Health · 100 Hz) appears at the top — requires Samsung Health Platform developer mode (see above)
2. Enter a label for the data (e.g. walking, resting, elevated)
3. Select a duration
   • 2–10 s for motion / IMU sensors
   • 15–30 s for PPG / heart rate
4. Tap RECORD — a 3-second countdown plays before recording starts
5. The sample uploads automatically to Edge Impulse when recording finishes

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Sensor Notes

PPG (Samsung Health Sensor SDK)

• Uses PPG_ON_DEMAND tracker at 100 Hz — provides true continuous raw waveform data
• Uploads green, IR, and red channels as a 3-axis signal at 10 ms interval
• Samsung Health Platform developer mode must be enabled on the watch (see setup above)
• Permissions must be re-granted after every Android Studio deploy (see above)
• Requires the watch to be worn on the wrist during recording

Microphone (Audio)

• Records raw PCM audio at 16 kHz mono and uploads as a WAV file — ready for keyword spotting and audio classification projects in Edge Impulse
• Requires RECORD_AUDIO permission (prompted on first launch)
• Use durations of 1–2 s per sample for keyword spotting

Heart Rate (Android SensorManager)

• Processed BPM value, not a raw waveform
• Needs 5–10 seconds to warm up — use recordings of at least 30 s
• Requires BODY_SENSORS permission (prompted on first launch)

Other sensors

• Sensors with no data in a session are silently skipped — they do not cause the upload to fail