for the Android app "HausFunk — Sonos Announcement"
Last updated: March 2026
1. Data Controller
The controller within the meaning of the General Data Protection Regulation (GDPR) and other applicable data protection laws is:
2. Overview of Data Processing
HausFunk is an Android app that allows voice announcements to be played on Sonos speakers within the local home network.
PRIVACY BY DESIGN: HAUSFUNK WAS DELIBERATELY DESIGNED WITH YOUR DATA PROTECTION AT ITS CORE. THE APP WORKS ENTIRELY OFFLINE AND LOCALLY. NO PERSONAL DATA IS TRANSMITTED TO EXTERNAL SERVERS, CLOUD SERVICES, OR THIRD PARTIES. THERE IS NO USER ACCOUNT, NO ADVERTISING, NO ANALYTICS TOOLS, AND NO TRACKING SERVICES.
3. Data Processed in Detail
3.1 Microphone Audio (Voice Data)
What: When you press the talk button in the app, your smartphone's microphone is activated and your voice is recorded.
How: The app first records your announcement as a temporary audio file (WAV format) in the device's internal cache. After recording, the app makes this file available via a temporary local HTTP server on your device, so that the selected Sonos speakers can retrieve and play the recording via UPnP protocol over your local Wi-Fi network. This is not a real-time transmission but a two-step process: first recording, then playback.
Temporary storage: During the recording and playback process, a temporary audio file is created in the app's internal cache directory. This file is automatically deleted after playback is complete. The file is located in the protected app storage area and is not accessible to other apps. No permanent storage of audio data takes place. The setting allowBackup="false" also ensures that temporary data is not included in Android backups.
Transmission: Exclusively to Sonos speakers on the local network. No transmission to the internet.
Legal basis: Consent pursuant to Art. 6(1)(a) GDPR. Consent is given by granting the Android microphone permission and by actively pressing the talk button. You can revoke your consent at any time by withdrawing the microphone permission in the Android system settings.
3.2 Network Discovery (UPnP/SSDP Discovery)
What: When the app starts and during manual refresh, your local Wi-Fi network is scanned for Sonos speakers.
How: The app sends a standardized UPnP/SSDP search request (multicast) to your local network. Sonos speakers respond with their device information.
Device data collected: Room name of the speaker (e.g., "Living Room"), model designation (e.g., "Sonos One"), local IP address of the speaker on the home network, and a device-internal identifier (UUID).
Storage: Device data collected during network discovery (IP addresses, UUIDs) is only held in working memory while the app is open and discarded when the app is closed. The exception is the room names of Sonos speakers: these are stored persistently on your device in connection with your room selection and volume settings (see Section 3.4).
Transmission: The search request and responses remain entirely within the local network. No data is transmitted to the internet.
Legal basis: Legitimate interest pursuant to Art. 6(1)(f) GDPR. Network discovery is technically necessary to enable the core function of the app (selection and playback on speakers). Without this processing, the app cannot function.
3.3 Local Network Communication (Audio Streaming and Device Control)
What: To transmit the announcement and control the speakers (volume, playback), the app communicates directly with the Sonos devices on your local network.
Data technically transmitted: Your smartphone's local IP address is made known to the Sonos speakers as part of network communication (this is technically unavoidable in any network communication). The audio stream is provided by a temporary HTTP server on your smartphone and retrieved by the speakers.
Transmission: Exclusively within the local network. None of the mentioned data leaves your home network.
Legal basis: Legitimate interest pursuant to Art. 6(1)(f) GDPR (technically necessary for the core function).
3.4 App Settings and Room Configuration
What: The app persistently stores the following settings on your device so you don't have to configure them again each time you start the app:
Your selected rooms (stored as room names of your Sonos speakers, e.g., "Living Room", "Kitchen"), the set volume per room, and the preferred recording mode (push-to-talk or toggle).
Storage: Exclusively locally on your device in the app's internal settings (Android DataStore). The room names correspond to the designations you assigned in your Sonos system and generally do not constitute personal data. If you have assigned personal names to rooms (e.g., "Anna's Room"), these are also stored locally. All stored settings are automatically deleted when the app is uninstalled. The setting allowBackup="false" ensures that this data is not included in Android backups.
Legal basis: Legitimate interest pursuant to Art. 6(1)(f) GDPR (convenience function for storing user settings so the app can be used without reconfiguration).
4. Data NOT Collected
For clarification: HausFunk expressly does not collect, process, or store any of the following data:
No location data (GPS, network location). No contacts, photos, or other files on your device. No device IDs, advertising IDs, or fingerprints. No usage or behavioral analytics. No crash reports. No personal data via internet connections. The app does not establish an internet connection at any time.
5. Disclosure to Third Parties
There is no disclosure of personal data to third parties. The app contains no third-party software development kits (SDKs) that independently process data, no advertising networks, no analytics or tracking services, and no cloud connections or external server communication.
Where open-source software libraries are used in the development of the app (e.g., for HTTP server or network communication), these do not independently process personal data and do not transmit data to third parties.
6. Transfer to Third Countries
No data is transferred to countries outside the European Union or the European Economic Area. All data processing takes place locally on your device and within your local network.
7. Data Retention
Audio data: Temporary audio files are created in the app cache and automatically deleted after playback is complete. No permanent storage of audio data takes place.
Network data: Technical device data from UPnP discovery (IP addresses, UUIDs, model designations) is only held in working memory while the app is active and discarded when the app is closed.
Room configuration: Selected room names and volume settings per room are stored persistently locally on your device and remain there until the app is uninstalled or the app data is manually deleted in the Android settings.
Other settings: The preferred recording mode is also stored persistently locally and automatically deleted upon uninstallation.
8. Your Rights Under the GDPR
You have the following rights with regard to your personal data:
Right of access (Art. 15 GDPR): You may request information about whether and which personal data is being processed.
Right to rectification (Art. 16 GDPR): You may request the correction of inaccurate data.
Right to erasure (Art. 17 GDPR): You may request the deletion of your data.
Right to restriction of processing (Art. 18 GDPR): You may request the restriction of processing.
Right to data portability (Art. 20 GDPR): You may request to receive the data you provided in a structured, commonly used, and machine-readable format.
Right to object (Art. 21 GDPR): You may object to the processing of your data at any time, insofar as it is based on Art. 6(1)(f) GDPR (legitimate interest).
Right to withdraw consent (Art. 7(3) GDPR): You may withdraw consent (microphone permission) at any time with effect for the future by revoking the permission in the Android system settings.
Right to lodge a complaint with a supervisory authority (Art. 77 GDPR): You have the right to lodge a complaint with a data protection supervisory authority. The competent authority is:
Der Landesbeauftragte für den Datenschutz und die Informationsfreiheit Baden-Württemberg
Lautenschlagerstraße 20
70173 Stuttgart, Germany
www.baden-wuerttemberg.datenschutz.de
Practical note: HausFunk does not store personal data on external servers. Locally stored settings (room selection, volume) can be removed at any time by clearing the app data in the Android settings or by uninstalling the app. The microphone permission can be revoked at any time in the Android system settings.
9. Android Permissions in Detail
HausFunk requires the following Android permissions:
Microphone (RECORD_AUDIO): Required to record your voice for transmission to Sonos speakers. The microphone is only active while you press the talk button. The app does not access the microphone when idle.
Wi-Fi information (ACCESS_WIFI_STATE, ACCESS_NETWORK_STATE): Required to check the connection status of your Wi-Fi and determine your device's local IP address for the audio stream.
Network access (INTERNET): Technically required by Android for local network communication (UPnP/HTTP). The app uses this permission exclusively for communication within the local network. No internet connections are established.
Multicast (CHANGE_WIFI_MULTICAST_STATE): Required for UPnP/SSDP discovery of Sonos speakers on the local network. Without this permission, devices on the network cannot be automatically detected.
10. Use by Minors
HausFunk is rated 12+ in the Google Play Store and is primarily intended for adult users. However, the app may also be used by minors in a family setting.
If persons under 16 years of age use the app, this should be done with the knowledge and consent of a parent or guardian (Art. 8 GDPR). Since the app does not store, transmit, or share personal data with third parties, the risk to minors is minimal.
The app deliberately does not collect data that would enable the identification of minors. The provider is committed to following Google Play's policies for family-friendly content.
11. Data Security
The app processes data exclusively locally and within the local network. Audio data is transmitted unencrypted via the UPnP protocol over the local Wi-Fi, as this conforms to the UPnP standard and is required for communication with Sonos speakers. The security of the transmission therefore depends on the encryption of your Wi-Fi network (e.g., WPA2/WPA3). We recommend using a password-protected Wi-Fi network.
Since no data leaves the local network, the risk of a data leak is significantly reduced compared to cloud-based services. Temporary audio files are stored in the protected app cache, which is not accessible to other apps, and are automatically deleted after playback. Persistently stored settings (room selection, volume) are also located in the protected app storage and are not included in Android backups (allowBackup="false").
12. No Automated Decision-Making
No automated decision-making including profiling within the meaning of Art. 22 GDPR takes place.
13. Google Play Store
HausFunk is distributed via the Google Play Store. When downloading and updating the app, certain data is processed by Google (e.g., username, email address, device identifier, installed apps, device information). This data processing is beyond our control and responsibility. For more information, please refer to Google's Privacy Policy.
14. Changes to This Privacy Policy
This privacy policy will be updated as needed, particularly in the event of changes to app functionality or legal requirements. The current version is always available at wagnernet.org/hausfunk/privacy-policy. The date of the last update can be found at the beginning of this document.
15. Contact for Privacy Inquiries
For questions about data protection, to exercise your rights, or for complaints, please contact: