Indie Apps Lab

Privacy Policy – Luma Lux

Last updated: 2026-01-10

1. Introduction

This Privacy Policy explains how the Luma Lux mobile application (“Luma Lux”, “the App”) developed by Indie Apps Lab (“we”, “us”, “our”) handles your information.

Luma Lux is a light meter. It uses your device’s ambient light sensor to measure illumination in lux (lx) and shows the result on screen. The App is designed to be as privacy-friendly as possible and to minimise the data we process.

This Privacy Policy applies to the Luma Lux mobile application and describes how it handles data on your device.

2. Key Points at a Glance

This short summary explains Luma Lux’s overall approach to privacy and data:

  • No accounts or sign-in. You can use the App without creating an account.
  • No server collection of your measurements. We do not send your light measurements or measurement history to our servers.
  • On-device processing. Light sensor readings are processed on your device to calculate and display lux values.
  • No ads. The App does not include advertising networks.
  • Limited diagnostics via Google Firebase. The App uses Firebase to help us understand crashes and improve stability. This may involve collecting technical diagnostic data (see section 7).
  • Data leaves your device only if you share it. Measurement data (for example CSV/JSON exports) leaves your device only when you actively export or share it through other apps or services.

3. Data Processed by Luma Lux

Luma Lux is designed to work primarily with data that never leaves your device. Below is an overview of what the App uses and how.

3.1 Light Sensor Data (Ambient Light / Lux)

  • The App uses the device’s ambient light sensor to access live illumination readings and calculate/display the current value in lux (lx).
  • Sensor readings are processed only on your device to show real-time values and charts.
  • The App does not transmit your raw light readings to our servers.

3.2 Measurement History (Local Storage)

  • Luma Lux may store a history of your measurement sessions (for example: average, minimum and maximum lux during a session, timestamps and optional names/labels you assign to sessions).
  • This information is stored locally on your device in the App’s private storage and is not automatically uploaded to our servers.
  • We do not have access to this local history and cannot retrieve it from your device.

3.3 App Settings and Configuration

  • The App stores certain preferences (for example: theme, language, calibration multiplier/offset, history options, screen-on behaviour) locally on your device so that the App can remember your choices between sessions.
  • These settings are stored in the App’s private storage and are not sent to us.

3.4 Personal Data

Luma Lux does not require you to create an account, sign in, or provide your name, email address or other personal details in order to use the App.

We do not intentionally collect your light measurement data on our servers. However, the App uses Google Firebase for diagnostics (see section 7), which may process certain technical identifiers and crash/performance information.

4. Exporting and Sharing the Measurements

The App includes features that let you export or share your measurement history (for example, as files such as CSV or JSON, or via the system share sheet).

  • When you export or share measurements, the selected data is passed to the app or service you choose (for example, email, messaging, cloud storage).
  • We do not receive a copy of this exported data. It is handled by the third-party apps or services you select, under their own privacy policies.
  • You can always stop exporting or sharing and can delete the exported files or messages using the tools provided by those third-party services.

5. Permissions Used by the App

To function correctly, the App may request certain permissions from your device:

  • Light sensor – used to measure illumination in real time. On most Android devices, access to the ambient light sensor does not require a runtime permission prompt.

The App uses the platform’s standard storage mechanisms for saving local data (app data inside the operating system sandbox) and does not request separate storage permissions to access your photos, media or files.

You can manage permissions for Luma Lux at any time in your device’s system settings.

6. Local Processing and Storage

  • All processing of sensor readings for measurement is done directly on your device.
  • Measurement history and settings are stored only in the App’s local storage on your device.
  • We do not remotely store your light measurements or settings on our own servers.

7. Third-Party Services and App Stores

The current version of Luma Lux integrates with Google Firebase to help us improve app stability and fix bugs. Firebase may collect and process diagnostic information such as crash logs, device model, operating system version, app version, and other technical data necessary for reliability and troubleshooting.

  • We use Firebase primarily for crash reporting/diagnostics (for example, Firebase Crashlytics) to identify and fix issues.
  • Firebase is a third-party service operated by Google and is subject to its own privacy documentation and terms.
  • Your measurement history and light sensor readings are intended to remain on-device and are not designed to be uploaded to our servers.

If a future version adds additional services (for example, ads or analytics), this Privacy Policy will be updated and the change will be clearly reflected here and in the app store listing. Where required by law, we will also ask for your consent inside the App.

Please note that app stores and platform providers (such as Google Play and your device manufacturer) may collect their own usage data in accordance with their own privacy policies. We do not control their collection or use of such data.

8. Data Sharing and Legal Disclosures

  • We do not sell or rent your personal data.
  • We do not share your measurement history or light sensor readings with third parties, as this data is not sent to us in the first place.
  • We may disclose information only if required to do so by applicable law or in response to valid legal requests (for example, a court order). In normal operation, we do not hold your measurement history on our servers.

9. Data Retention and Deletion

Because the App does not store your measurement history on our servers, there is no server-side retention period for that data.

On your device:

  • Measurement history and settings remain on your device until you delete them or uninstall the App.
  • You can remove this data by clearing the App’s data or uninstalling Luma Lux via your device settings.
  • Exported files or shares (for example, CSV/JSON you have sent by email or stored in cloud services) need to be deleted using those third-party services.

10. Children’s Privacy

Luma Lux is not specifically directed at children and does not knowingly collect personal data from children under the age of 13 (or other age defined by local law).

11. Your Privacy Rights

Depending on your location, you may have certain rights regarding your personal data under local data protection laws (for example, the GDPR in the European Union / EEA or similar laws in other regions).

While Luma Lux is built to avoid collecting measurement data on our side, we still want to be transparent about your options:

  • Access / information. You can contact us if you have questions about what data the App uses and how.
  • Correction / deletion. You can delete local data by clearing the App’s storage or uninstalling the App from your device.
  • Control of permissions. If your device/OS provides controls related to sensors, you can manage them in your device settings.

12. International Users

The App may be used by users in different countries. Firebase (as a third-party provider) may process diagnostic data on infrastructure located in different regions. For details, please refer to Google/Firebase documentation.

13. Changes to This Privacy Policy

We may update this Privacy Policy from time to time, for example if we change how the App works or if we add new features such as analytics or advertising.

  • When we make significant changes, we will update the “Last updated” date at the top of this page.
  • Where appropriate, we may also provide an in-app notice or mention changes in the app store listing.

14. Contact

For the purposes of applicable data protection laws, the data controller for Luma Lux is Indie Apps Lab.

If you have any questions about this Privacy Policy or about how Luma Lux handles your data, please contact us:

Email: indieappslab+support@gmail.com

By installing and using Luma Lux, you acknowledge that you have read and understood this Privacy Policy.