RF[email protected]:~$ ./rf_sentinel --passive
RF_SENTINEL - police detector for Android
A free, open-source police detector for Android. It listens to the Bluetooth LE advertisements and WiFi beacons around you and flags police and surveillance equipment: body cameras, Flock and other plate-reader cameras, patrol-vehicle gear, trackers following you, Remote ID drones and camera glasses. It also watches the cell network for fake-tower (IMSI catcher) signs.
RX ONLYNo root · no Termux · no account · no analytics · GPL-3.0 · Android 8.0+ (64-bit)
Signed APK from GitHub Releases. Not on Google Play. Install guide · Q&A
Police equipment it detects
| Category | Examples | How |
|---|---|---|
| Body cameras | Axon (TASER), Motorola / WatchGuard, Digital Ally, Zepcam, Vievu, Utility, Getac, in-car video | BWCDEVICE payload tag, company ID 0x034D, service UUIDs 0xFC81 / 0xFE6B / 0xFE6C, IEEE vendor prefixes |
| License-plate readers (ALPR) | Flock Safety, Genetec, Perceptics, Quercus, Tattile | Flock- SSIDs, Penguin- / FS- / FS Ext Battery BLE names, company ID 0x09C8, plus OpenStreetMap / DeFlock camera locations |
| Speed & red-light cameras | Fixed cameras mapped in OpenStreetMap | Offline map layer, warned about ~30 s ahead with the mapped limit |
| Audio sensors | Flock Raven gunshot detectors | 128-bit service UUIDs with short IDs 0x3100-0x3500 |
| Patrol vehicles | Two or more kinds of police-type gear moving together | RSSI correlation (Pearson r ≥ 0.6 over ≥ 8 s) across body cam, radio, in-car router, printer, rugged laptop roles |
| Public-safety gear | P25 / TETRA radio makers, in-car cellular routers (Sierra Wireless, Cradlepoint, Peplink, Inseego), in-car printers (Zebra, Brother), police radar makers, vehicle upfit, breath / drug screening devices | Company IDs, UUIDs, IEEE prefixes, Zebra factory-serial names |
| Trackers | AirTag & Find My, Google Find Hub, Samsung SmartTag, Tile, Chipolo | Separated-from-owner frames, then follow detection (default 10 min and 800 m with you) |
| Drones | Any ASTM F3411 / FAA Remote ID broadcaster (DJI, Skydio, Autel, Parrot...) | Decoded Remote ID over BLE and WiFi: serial, position, altitude, speed, heading, operator location |
| Camera glasses | Ray-Ban / Oakley Meta, Snap Spectacles, Vuzix, HeyCyan-based glasses such as Nilox Smart AI Glasses | Luxottica 0x0D53, Snap 0x03C2, Vuzix 0x060C, Meta UUIDs |
| Fake cell towers | IMSI catchers / cell-site simulators | Test MCCs, sudden 4G→2G, cloned or reserved cell IDs, unexpected networks (no root) |
| Card skimmers | Bluetooth modules inside gas-pump and ATM skimmers | HC-05 / HC-06 / HC-03 / RN42 / BT04-A names, serial-port service |
| Hacking tools (optional) | Flipper Zero, Pwnagotchi, WiFi Pineapple, deauthers, evil twin WiFi, Bluetooth spam floods, WiFi deauth attacks | Flipper IDs, Pwnagotchi beacon JSON, default network names, same network name from two makers with mismatched security, bursts of pairing pop-ups; with a USB WiFi adapter, floods of deauthentication frames knocking devices off a network |
| Emergency vehicles (V2X, Europe) | Police, fire, ambulance and safety cars broadcasting European car-to-car radio (ITS-G5) | An ESP32-C5 with the V2X2MAP firmware: the vehicle's role, light bar and siren state and its own position, and "emergency vehicle approaching" warnings. Not in North America (C-V2X) |
| Action & hidden cameras (optional) | GoPro, Insta360, DJI Osmo, YI, SJCAM, AKASO and other action cams; WiFi spy cameras in setup mode (V380, LookCam Pro...) | Bluetooth company IDs and services, maker prefixes, default camera and setup-hotspot network names |
| Police aircraft (online, optional) | Police, sheriff, state patrol, federal and RCMP / provincial police aircraft; unlisted aircraft circling low overhead | Community ADS-B feeds (adsb.fi / adsb.lol) matched against ~1,400 law-enforcement airframes from the FAA and Transport Canada registries |
| Waze reports (online, optional) | Police reported by Waze users, and any other kind you tick (accidents, hazards, road closures, traffic jams), inside an alert range you choose | Your own OpenWeb Ninja API key, or Waze direct (opt-in: sends Waze your IP address and a position rounded to a 1 km grid); scored by distance and age and re-scored every second as you move; third-party service, at your own risk |
Every match shows its evidence, its source and a confidence tier: weak (< 50), probable (50-79) or strong (80+). Full rules: how detection works and the signature reference.
What happens to every packet
Illustrative trace: actual scores depend on what each device advertises. The app logs the evidence the same way on each device's detail screen.
Features
Live list, radar & map
Every device in range (each leaves 30 s after it was last heard on Bluetooth, 60 s on WiFi, adjustable) with vendor, type, radio, RSSI, rough distance and NEW / ★ / FOLLOWING badges. Flagged devices sort first. Filter chips with live counts. Show the list, the radar and the map one at a time or together, resizable.
Alerts
Sound, vibration pattern per tier (1 / 2 / 3 pulses), spoken announcements through the phone's TTS, optional radar-detector beeps that speed up as a flagged device gets closer, discreet mode, floating threat bubble over Waze or Google Maps with a pop-up saying what was detected. Radar-detector sound style with selectable alert effects and an optional intro.
Navigation
Turn-by-turn directions on the map: search a place (Home, Work, starred and recent places are kept on the phone; or long-press the map), pick one of up to three routes, avoid tolls, highways or ferries, and go. A banner shows the next turn, lane arrows and the turn after it; spoken directions play as navigation audio so your music dips under them; it re-routes by itself, takes stops, and finds petrol, charging or food along your route. Your arrival time follows how you really drive. Open the destination in Google Maps or Waze if you prefer. No live traffic. The map goes to its night look after sunset.
Map & traces
A vector map (OpenFreeMap, OpenStreetMap data, or Mapbox if you prefer) with your GPS trace, devices placed where their signal peaked and flagged ones pinpointed from every spot you passed (with the circle they're very likely in), history heatmap and timeline, offline known-camera layer. North up, heading up, or a 3D driving view like a navigation app that zooms with your speed, with the default zoom and angle in Settings; a light map and a readable night map with shops, landmarks and one-way arrows. Optional CCTV layer: street, shop and building cameras mapped in OpenStreetMap, with their view cones.
Android Auto
Police alerts on the car screen as messages read aloud (reply "mute"), and an RF Sentinel screen with threats, cameras ahead, recent alerts and Scan / Mute buttons. The full car app with live map and navigation runs on Google's Desktop Head Unit. Details
Auto start in the car
Starts when the phone connects to your car's Bluetooth or Android Auto, stops when you leave.
Tools
Cell towers (serving and neighbour cells, IDs, channel, signal, history, optional map layer and change alert) and WiFi channel / spectrum analyzers for 2.4, 5 and 6 GHz.
USB WiFi adapters
ALFA AWUS036ACS, AWUS1900, AWUS036ACM, AWUS036H, AWUS036NH / NEH, AWUS036NHA and AWUS036AXML (experimental), TP-Link Archer T3U and other RTL8812BU dongles - 2.4 GHz, 5 GHz on the AC adapters and 6 GHz on the WiFi 6E AWUS036AXML - in receive-only monitor mode over OTG, no root: no scan limit, longer range, devices connected to networks, and the network names devices ask for. Details
ESP32 boards
OUI-Spy over USB OTG or Bluetooth, GhostESP and Marauder over USB (dual-band on ESP32-C5, or through a Flipper Zero with a BFFB). The board's detections merge into the app. Details
Device details
Evidence, identity, decoded protocol data, signal graph, Locate mode (beeps faster as you get closer, and keeps following a tag when it changes its address), history and the raw advertisement. Search every device the app remembers, in range or not, by address, name, vendor, type or your note.
Export
CSV, JSON, KML, GPX, GeoJSON. Everything stays on the phone until you export or share it.
13 themes
Including DedSec (Watch Dogs 2) and fsociety (Mr. Robot) fan themes with animated terminal headers, Night Drive red HUD, Night Vision, Amber CRT.
Screenshots
Screenshots use made-up demo devices run through the real detection pipeline.
Compared with other options
| RF Sentinel | Crowd-reported apps (Waze) | Phone's built-in tracker alerts | |
|---|---|---|---|
| Price | Free | Free | Free |
| Open source | GPL-3.0 | No | No |
| Works where nobody reported | Yes, reads the equipment's own signals | No, needs other drivers | Trackers only |
| Account / tracking | None | Location shared with the service | Phone account |
| Install | Regular APK | App store | Built in |
| Bluetooth LE / WiFi signatures | Yes | No | Trackers only |
| Police / ALPR / body cam rules | Yes, sourced | User reports | No |
| Remote ID drone decode | Yes | No | No |
| Fake cell tower signs | Yes | No | Android 15+ only (network notifications) |
| Android Auto | Yes, alerts and a status screen | Yes | No |
Crowd-reported apps and RF Sentinel work well together: one knows what other drivers saw, the other hears the equipment itself.
Guides
Detect police with Android
Body cams, radios, patrol-vehicle kits, e-ticket printers.
Flock & ALPR cameras
Radio signatures plus the OpenStreetMap / DeFlock camera map.
Stingray / IMSI catcher
What a non-rooted phone can and can't see.
AirTag & tracker detection
Find My, Find Hub, SmartTag, Tile and Chipolo on Android.
Remote ID drone detector
Drone and operator position from the broadcast.
Smart glasses detector
Ray-Ban Meta, Spectacles, Vuzix nearby.
Compared with other tools
Flock You, OUI-Spy, Wardrive Go, Fieldwatch, AirGuard and more, and which ones work together.
Privacy
- Receive-only. The app never transmits, jams, spoofs or connects to the devices it detects.
- No accounts, no cloud, no analytics. Detections live in a local database excluded from cloud backup.
- Network use: the map (vector tiles from OpenFreeMap, OpenStreetMap data, or from Mapbox if you pick it in Settings with Mapbox's own usage statistics switched off), camera data (Overpass API, DeFlock CDN), the roads of your area while the Waze option to alert only for reports on your road is on, and, when you search for a destination or start a route, Photon and Nominatim (place search) and Valhalla (routes), only when used. Those servers see your IP and the area or route, never your scans. Two optional sources are off by default: police aircraft (a position rounded to ~1 km goes to the ADS-B feeds adsb.fi / adsb.lol) and Waze reports, either through your own OpenWeb Ninja key or straight from Waze (Waze direct: your IP address and a position rounded to a 1 km grid), at your own risk.
- Data leaves the phone only when you export or share it.