Android Exposed

Minimal Android app that exposes phone sensor data through a local HTTP server on port 8765.

Build and run

Open the project in Android Studio and run the app configuration on a physical phone.

Or from PowerShell:

.\run.ps1

The app opens stopped. Choose the sensor sources and Hz values you want, then tap Start sensor exposure.

When exposure is running, the app uses a foreground service with a persistent notification. This keeps the local server alive when the app is not visible or the phone screen is off.

Phone controls

Main screen:

• Start sensor exposure / Stop sensor exposure turns the local server and sensor streaming on or off.
• Stream all available Android sensors enables every detected Android sensor that supports normal listener callbacks.
• Each detected source has a checkbox and Hz field.
• Apply selection updates the running server without reinstalling or restarting the app.
• Request permissions for enabled sources asks only for permissions needed by the currently enabled sources.

Live screen:

• Shows the latest sample produced for each active source.
• Shows produced count, sent count, approximate Hz, and last sample time.
• Useful for checking that the phone itself is producing data.

Output screen:

• Shows the latest sample sent to a connected receiving app.
• Shows sent count and last sent time per source.
• Shows a clear message when no receiving app is connected.

Connect over USB

adb devices
adb forward tcp:8765 tcp:8765
curl http://127.0.0.1:8765/health
curl http://127.0.0.1:8765/sensors
python tools/read_stream.py
python tools/live_output.py

Tap Start sensor exposure on the phone before running the curl or Python commands.

Endpoints

GET  /health
GET  /sensors
GET  /config
POST /config
GET  /stream

/stream returns newline-delimited JSON. Android sensors use timestamp_ns. GPS and mobile signal use timestamp_ms.

Example config:

curl -X POST http://127.0.0.1:8765/config \
  -H "Content-Type: application/json" \
  -d "{\"sensors\":{\"accelerometer\":200,\"gyroscope\":200,\"rotation_vector\":100,\"magnetometer\":50,\"gps\":1,\"mobile_signal\":1},\"include_all_available\":false}"

Use include_all_available: true to stream every detected Android sensor that supports normal listener callbacks.

Python stream reader

python tools/read_stream.py
python tools/read_stream.py --output samples.jsonl
python tools/read_stream.py --limit 100

Live output dashboard

python tools/live_output.py
python tools/live_output.py --output samples.jsonl

The dashboard shows every live /stream source with counts, estimated Hz, and latest values.

Notes

Android requires a foreground-service notification for reliable background operation. This app starts with the connectedDevice foreground-service type because the phone is serving sensor data to an external computer over ADB/TCP. If location permission is granted, it also enables the location foreground-service type. The app holds a partial wake lock while the service is running so the CPU can keep processing sensor/server work with the screen off.

GPS needs location permission and an enabled location provider.

Mobile signal uses Android's public TelephonyManager.getSignalStrength() API on Android 9+ and needs READ_PHONE_STATE. Some devices or carriers may still return no signal details.