Eardrum

Background audio recorder for Android

Instructions

1. Accept permissions:

   • Manifest.permission.RECORD_AUDIO allows Eardrum to hear audio.
   • Manifest.permission.WRITE_EXTERNAL_STORAGE allows Eardrum to remember audio.
   • android.permission.ACCESS_COARSE_LOCATION, android.permission.ACCESS_FINE_LOCATION, and android.permission.ACCESS_BACKGROUND_LOCATION allow Eardrum to record location.

2. AudioRecorderService gets started by:

   • MainActivity every time you enable Eardrum.
   • AlarmManager every interval configurable on the settings page.

3. AudioRecorderService creates a new recording or stops a recording every time it's started:

   • Records audio in the background using your device's main microphone.
   • Writes audio to a file with pattern yyyy-MM-dd'T'HH:mm:ss'Z.ext.
   • Stores the files at /storage/emulated/0/Android/data/com.miguelrochefort.eardrum/.
   • Uploads the file with sensor data to configured server.

Settings

There are five main settings that can be accessed on the app main page

1. Enable recording: Start or stop Eardrum
2. Recording length: Length of recording
3. Recording interval: Iterval between recordings
4. Media format: Which format to save audio in
5. API endpoint address: Address of server to upload to

Screenshot

Repository layout

This is a standard Android application repository. The app currently targets SDK 29 with a min of SDK 21 and a compile of SDK 31. All the app files are written in kotlin and the gradle scripts should be recently up to date as of the writing of this. The main app is composed of a few files

• Constants.kt holds the constants for other parts of the program
• Status.kt holds the status object for organizing data
• UI.kt holds the compose UI for the settings page
• MainActivity.kt holds the main thread of the application, which controls the settings page and starts and stops the recorder service
• AudioRecorderService.kt holds the audio recorder service, which manages all the recording of audio and other sensors and the uploading of data to the main server

Notes

• Only briefly tested on a Nexus 4 running Android 5.1 and Android 10.