Privacy Policy

SignalScan for Android · Effective 28 October 2026

In short

SignalScan keeps what it records on your phone. There are no accounts, ads, analytics or crash reporting, and we, the developer, never receive your scans. Data leaves the app only when you start a map or tower download, export a file, hand a location to a maps app, copy an identifier, or buy Pro.

What the app records

To show what is around you, SignalScan reads what nearby radios broadcast:

• Wi-Fi: network names (SSIDs), access point addresses (BSSIDs), channel, security type and signal strength;
• Bluetooth Low Energy: device names and addresses, advertised data and signal strength;
• Cell: the identifiers and signal strength of the cell towers your phone hears.

Each reading is stored with the time and your phone's location when it was heard, so the Log and the Map can show where a signal was. The app also keeps the surveys you record, the devices you save along with any names and notes you give them, and your settings.

These are signals that other people's devices broadcast publicly. SignalScan does not connect to those devices or read anything they do not broadcast.

Where it is kept

Everything above stays in the app's private storage on your phone. It is not uploaded, and it is left out of Android's cloud backup and of transfers to a new phone. You choose how long each radio's Log is kept in Settings › Log retention, and you can clear the Log or delete surveys at any time. Uninstalling the app deletes all of it.

Permissions

• Location and nearby devices: Android requires these to scan Wi-Fi, Bluetooth and cell signals, and the app uses your location to place readings on the Map.
• Notifications: to show alerts you turn on and the notification for scanning with the screen off.
• Foreground service: only while scanning with the screen off or recording a survey with the screen off, both of which you turn on yourself.

When data leaves your phone

Offline map download. If you download a map, the app fetches the list of map builds and the map tiles from Protomaps (build-metadata.protomaps.dev and build.protomaps.com). It requests only the parts of the map covering the places in your Log, so that server can work out the general area those places are in. It also receives your IP address, as any website does.

Cell tower database download. If you download towers, the app fetches tower lists from OpenCelliD (opencellid.org) using your own OpenCelliD API key. The request names the mobile country codes in your Log, so OpenCelliD learns which countries' towers you asked for. It also receives your IP address and your key, under OpenCelliD's own terms.

Exports. When you export the Log or a survey, the app builds a CSV or JSONL file and hands it to whatever app you choose in Android's share sheet. Before each export, a preview shows what the file will contain, and you can remove or pseudonymise device identifiers and remove or coarsen locations. Once shared, the file is in the hands of the app and the people you sent it to.

Navigate and copy. Navigate on a Map callout gives that device's coordinates and label to the maps app you choose. Copy puts an identifier, such as an address, on the clipboard, where other apps can read it.

Buying Pro. Purchases go through Google Play. Google processes your payment under the Google Privacy Policy. The app receives only a confirmation that Pro is unlocked, never your payment details.

Both downloads are optional and run only when you start them. The app makes no other network requests.

Children

SignalScan is not directed at children under 13 and collects no data from anyone, children included.

Changes and contact

Developer: Black Vessel Labs. Any changes to this policy will be published on this page, with a new effective date. Questions: blackvessellabs@gmail.com.