Frequently Asked Questions

SentryRF is a counter-surveillance Android app with on-device AI that detects hidden tracking devices like Apple AirTags, Tile trackers, Samsung SmartTags, and GPS devices. It uses Bluetooth and WiFi scanning to find wireless trackers, an on-device AI to classify threats, and Physical Sweep sensors (EMF, acoustic, pressure, light) to detect hidden cameras, electronic bugs, and other surveillance equipment. All AI training and processing happens locally on your phone.

Via Bluetooth/WiFi scanning: Apple AirTags, Tile trackers, Samsung SmartTags, unknown BLE beacons, WiFi-enabled trackers, and any broadcasting Bluetooth device. Via Physical Sweep: powered electronics hidden in walls or furniture (EMF), cheap spy cameras with ultrasonic oscillators (acoustic), infrared night-vision cameras (light sensor), and recently accessed sealed compartments (barometric pressure).

Physical Sweep is a feature that uses four of your phone's physical sensors simultaneously: the magnetometer for electromagnetic field detection, the microphone for ultrasonic emissions, the barometer for pressure changes in sealed spaces, and the ambient light sensor for infrared LED detection.

Physical Sweep uses consumer-grade phone sensors and can reliably detect powered electronics, cheap spy cameras, IR cameras, and sealed compartments. However, it cannot detect passive (unpowered) devices, professional-grade shielded equipment, powered-off devices, or devices inside metal enclosures. Building materials like rebar can cause false EMF readings, and acoustic detection requires a quiet environment. For high-stakes situations (corporate espionage, legal proceedings), professional counter-surveillance services with dedicated equipment are recommended. SentryRF is best used as a first-pass screening tool.

Parking Lot Mode is a dedicated vehicle sweep feature. When you park your car, activate Parking Lot Mode and walk around your vehicle to establish a baseline of nearby devices. On subsequent visits, SentryRF compares new scan results against your baseline and alerts you to any new or suspicious trackers that weren't previously present — such as a GPS tracker placed under your car.

Absolutely. All scan data, device history, threat logs, and settings are stored locally on your device — never uploaded to any server or cloud service. Data is automatically deleted after 30 days by default (adjustable from 7 to 90 days in Settings). SentryRF requires no account or sign-in, includes no analytics telemetry, and you can export or delete all data at any time from the Privacy & Security settings.

Yes — it's called Paired Sweep, and it works with up to three devices. Open Sound Locator on two or three phones running SentryRF, start one as the master and have the others join. A Wear OS watch counts as one of the three: it scans from your wrist and reports the tracker's signal back to your phone, so a phone plus a watch is already a paired sweep. The phones connect directly to each other over Bluetooth and WiFi — no internet, no account, and no data leaves your devices. Each phone reports how strong the tracker's signal is from where it sits, and the master combines those readings to estimate the tracker's position on a map. Two phones give you distance plus direction; three spread around a room place it on a map. If your phone has ultra-wideband (Pixel 6 Pro and newer Pro models, Galaxy S22 Ultra and newer, and other flagships), SentryRF uses it for centimetre-level ranging and falls back to Bluetooth or signal strength automatically on phones without it. Spread the phones at least 3 metres apart, keep them still during the sweep, and a triangle beats a straight line.

SentryRF is currently Android-only. An iOS version is not available yet and we're not announcing a date — we'd rather ship it right than ship it early. iPhone users who need protection now: an Android device running SentryRF works as a dedicated scanner for sweeping rooms, vehicles, and bags regardless of the phone you carry daily.

Desktop editions for Windows, macOS, and Linux are in development for desktop and operations-center use. There is no release date yet. The same patent-pending detection engine that powers the mobile app will carry across every platform. Email us to join the desktop waitlist.

Yes. SentryRF scans both Bluetooth and WiFi bands to detect trackers that operate on either frequency. For devices that don't broadcast wirelessly (wired cameras, passive GPS loggers), use the Physical Sweep feature to detect their electromagnetic signatures instead.

SentryRF watches the WiFi networks around you for signs of attack. It can detect fake networks pretending to be a real one (like a hotel or café WiFi), connections that suddenly become less secure, suspicious login pages designed to steal your passwords, and networks coming from unusual hardware. If you're already connected to a risky network, SentryRF warns you immediately.

Safe Zones let you mark trusted locations like your home or office. SentryRF takes a snapshot of all the devices normally present in that area, and from then on, only alerts you about new or unfamiliar devices. This dramatically reduces false alarms from your own devices, your neighbor's gadgets, and other harmless equipment you see every day.

Timeline Replay lets you watch a suspicious device's movement history play back on a map — like pressing rewind on a security camera. You can see exactly where the device was spotted, when it appeared at each location, and whether it's been following the same route as you. This is especially useful for building evidence or confirming that a device has been tracking you over time.

Yes — if you enable "Start on Boot" in Settings, SentryRF will automatically begin background scanning whenever your phone turns on. You'll never have a gap in protection, even after a restart or software update.

SentryRF comes with a 7-day free trial that gives you full access to every feature — nothing is locked or limited. After the trial, a subscription through Google Play keeps everything active. You can cancel anytime during the trial at no cost. See the Pricing page for details.

SentryRF includes a pure on-device AI that spots threats using advanced AI — sighting patterns, signal behavior, geographic spread, and more. It learns implicitly from your actions: whitelisting a device teaches it what's safe, keeping an alert teaches it what's suspicious. All training happens locally on your phone — no data is ever sent to any server. The AI also powers the Sound Locator with adaptive per-device calibration, tuning signal parameters for each specific tracker type.

SentryRF is available on Google Play and the Amazon Appstore (for Fire tablets). Download it for free — no account required. The Pro subscription unlocks advanced features and can be purchased directly in the app.

Your subscription is tied to the store account you bought it through, not to the individual phone. On your new device, sign in with the same Google account (or Amazon account, if you bought through the Amazon Appstore) you used originally, install SentryRF, open it, and use Restore Purchases in the subscription settings. If it still isn't recognised, contact support with your store and order number.

No, and that's deliberate for your privacy. SentryRF stores all scan history, device maps, and reports only on the device itself — there is no cloud account and no server-side copy, so there is nothing for us to restore. If you ever exported a PDF report or a backup file to email or cloud storage, that copy is still usable.

The paid features turn off, but the app doesn't take anything from you. Core detection — Bluetooth and WiFi scanning and analysis — stays available. Nothing is sent to us at any point.

Everything the app stored is deleted with it, because it only ever lived on your phone. Android automatically revokes every permission you granted the moment the app is removed. Nothing lingers on our side, because nothing was ever on our side.

The core detection features — Bluetooth and WiFi scanning and analysis — run without Google Play Services and work from a sideloaded APK. The paid subscription, however, uses Google Play Billing, which does require Play Services; there is currently no way around that for the paid tier. The free scanning features work fully offline.

You can locate any device the app detects, not just flagged ones — open the device from the list and use the locate tools. A device is only marked as a threat when the app observes genuinely suspicious behaviour, such as following you across locations over time. So a device can be present and locatable without being labelled a threat. That's intended, not a miss.

That's your phone's GPS settling. Indoors or in a moving vehicle the location bounces until it gets a stable fix. Move near a window or step outside, give it 15–30 seconds, and it should hold still. The map shows where devices were seen — it's a history map, not a live radar — so small movements as GPS updates are normal.

That was the custom alert-sound picker in Settings, which opens your file browser so you can choose your own notification tone — it looks empty if you have no sound files saved there. That is not the locator. To locate a device by sound, open the specific device and use “Make it beep” (on trackers that support it) or the proximity audio guide, which plays a built-in tone that speeds up as you get closer. Neither needs a file from your phone.

No, you don't need it. That refers to SentryPod, an optional add-on that plugs in for extended scanning. The app works fully on your phone by itself — you can ignore anything USB-related unless you choose to buy that accessory later.

Only if that person is carrying a device that is actively transmitting Bluetooth or WiFi. SentryRF detects wireless device signals, not people — it is not a human-presence or motion sensor. It's excellent at finding rogue devices (hidden cameras, bugs, trackers that emit a signal), but it can't sense a person through a wall or ceiling unless there's an emitting device involved.

Often, yes — a hidden camera that uses WiFi or Bluetooth will usually show up as a device in a scan. Do a slow Physical Sweep of the room; the sweep also listens for the high-frequency and ultrasonic tones some hidden electronics emit. Two low-tech checks complement the app well: look for the lens reflection with a flashlight in a darkened room, and physically inspect suspicious items such as smoke detectors, chargers, and vents.

It includes a rogue cell-tower monitor that flags known catcher signatures — things like a forced 2G downgrade, abnormal neighbour-cell behaviour, and readings that deviate from a learned baseline for your area. Important: each of these is a heuristic that surfaces suspicious patterns to investigate, not proof. Many of the same signatures occur for ordinary reasons — congestion, tower handoffs, carrier maintenance, weak coverage. Treat a flag as a prompt to look closer, not a confirmation.

No. SentryRF is detection only — for finding surveillance it listens and analyses, it never jams. (It does send a short Bluetooth pairing signal so two devices can find each other for Paired Sweep, but that's only for connecting your own devices, not for interfering with anything.) Signal jamming is illegal to build, sell, or operate in the U.S. under federal law, with no exception for personal use, and we will not build or support it.

Alerts come from real signal analysis, never from monetisation or fear tactics. They're based on signals and behaviour you can review and audit inside the app, and the AI learns from your corrections — marking a device as safe improves accuracy over time. Core detection, including the AI, is free.

No. All processing happens on your device. There is no SentryRF cloud, no remote database, and no telemetry. Detection logic and models are bundled in the app and run without sending your scan data anywhere. We don't collect, upload, or sell any of it.

Only what's needed for radio access and core function: Location (Android requires it before it will allow any Bluetooth or WiFi scan — a system rule, not a data grab), Bluetooth (to detect trackers, and to pair your own devices for Paired Sweep), Nearby WiFi (to see access points), Microphone (used only by the Physical Sweep to listen for the high-frequency and ultrasonic tones some hidden cameras and bugs emit — audio is analysed on the phone in real time and never recorded, stored, or sent anywhere), Foreground Service (to keep scanning while you sweep), and Notifications (to alert you). The app does not request access to your camera, contacts, SMS, or call logs.