Helios is built by Hellwarp. The short version: your scans, photos and location stay on your device. Helios has no accounts and no servers of its own. If you allow it, anonymous usage statistics and crash reports go to Google Firebase. Ads in the free version are handled by Google AdMob, and the Pro purchase by Google Play.
What data Helios collects
Usage statistics and crash reports — only if you allow them. Helios uses Google Firebase Analytics and Crashlytics to learn which steps people finish (opening the app, starting and finishing a scan, viewing and exporting a report) and what goes wrong (crashes, a camera that fails to open). In the EU, EEA and UK nothing is sent until you say yes; elsewhere it is on until you switch it off. You can change it any time in the app's menu (⚙): “Share anonymous usage statistics”.
What is sent: the event name and coarse details (the kind of site, e.g. roof or balcony; sky coverage and scan length in broad bands; PDF or image), your device model and Android version, the app version, your country (derived by Google from your IP address) and a random app-instance ID created by Firebase. Crash reports add the technical trace of the error. In the free version, AdMob also records how often an ad was requested and shown; these counts go into the same statistics.
What is never sent: your location or coordinates, site names, compass readings, yield figures, photos, scan data, your advertising ID, or anything you type. Statistics are never used to target ads. Google keeps them for 14 months.
Everything else is used locally and never transmitted:
| Data | How it's used | Where it lives |
|---|---|---|
| Your GPS location | Calculating where the sun is in the sky from your position | Device RAM only; written to disk only indirectly as the key for saved scans (3-decimal precision ≈ 110 m radius) |
| Camera frames | Detecting sky vs. obstructions in real time | Device RAM only; discarded after each frame |
| Scan photos (about eight per scan) | Showing in the report what blocks the sun | Device internal storage; excluded from Android backup; included in an exported report only if you leave “Include scan photos” on |
| Compass, accelerometer, gyroscope | Aligning the AR overlay to where you're pointing | Device RAM only |
| Sky obstruction maps | The "solar report" feature | Device internal storage (obstruction_grids/); never transmitted |
| Site labels & panel orientation choices | UI persistence — your settings stick across launches | Device internal storage (SharedPreferences); never transmitted |
Uninstalling Helios removes all of the above. You can also wipe it manually any time from the About sheet → "Reset all data".
Third-party services
Helios uses four Google services. They have their own privacy policies which apply to the data they collect:
Google Mobile Ads (AdMob) Free tier only
The free tier of Helios displays one banner ad on the Solar Report screen, served by Google AdMob. AdMob may collect:
- Your device's advertising ID (Android Ad ID)
- General app interaction data needed to deliver an ad
Google's privacy practices for this data are described at policies.google.com/technologies/ads. You can reset or limit your advertising ID at any time in your Android device settings (Settings → Privacy → Ads).
Upgrading to Helios Pro removes all ads. Pro Once Pro is unlocked, AdMob is not initialized and makes no network requests.
Google Play Billing Pro purchase only
When you purchase Helios Pro, the transaction goes through Google Play Billing. Google handles payment processing; Helios never sees your payment details. Google's data practices are at policies.google.com.
Google Firebase (Analytics, Crashlytics) Only if you allow it
Anonymous usage statistics and crash reports, as described above. Firebase does not receive your location, photos or scans. Google's privacy information for Firebase is at firebase.google.com/support/privacy.
Google Play Services Location
Helios uses Google's fused location provider to get an accurate GPS fix when you launch the app. The location is delivered locally to Helios — it isn't shared back to Google by us. Google's own use of location is governed by your device's privacy settings.
Permissions Helios requests
- Camera — required for the AR view. Frames are analysed in memory; the scan photos shown in the report stay on your device.
- Fine Location — required to compute the sun's path for your spot on Earth.
- Internet + Network State — required by AdMob (free tier), Google Play Billing (Pro purchase) and, if you allow it, Firebase usage statistics and crash reports.
- AD_ID — required by AdMob to read your advertising ID. You can reset or limit this in your Android settings.
- BILLING — implicit permission used by Google Play Billing.
Children
Helios is not directed at children under 13. We don't knowingly collect personal information from anyone. If you are under 13, please don't purchase Pro without a parent's involvement.
Changes to this policy
If we make material changes, the "Last updated" date at the top of this page will change and an in-app notification will appear on next launch.
Contact
Helios is a one-developer project. Reach out by email at [email protected].