It beeps at the gear that's watching you.
A pocket-sized ESP32 sweeps Bluetooth and Wi-Fi nonstop, matches what it hears against surveillance hardware, drone Remote ID, trackers and attack gear, and tells you which one by ear. Plug it in and walk away. The phone is optional.
No board yet? Kits and built units at signalsweep.net.
Flash it from this page
No Python, no PlatformIO, no drivers. Plug a XIAO ESP32-C5 or ESP32-S3 in with a data-capable USB-C cable. The flasher works out which one it is.
Flashing needs Web Serial: desktop Chrome, Edge or Opera. The app runs in the same browsers over Bluetooth or the cable, or on Android as an APK.
Hear it, don't read it
Every category gets its own sound and its own light, so it works face-down in a cupholder, a backpack or a jacket pocket. No screen required.
- ALPR / camera two long beeps
- Body cam long · short · short
- Drone rising trill
- Tracker fast ticking
Mute any category you don't care about. It's still detected and listed, just quiet. Three volumes, four LED modes, five themes.
But wait, there's more. It decodes the drone and where the pilot is standing. It hunts a tracker by ear, beeping faster as you close in. It catches a fake-AirTag spam storm and stops crying wolf. It names your neighbour's pwnagotchi. And when you want it quiet, it stops advertising entirely, so the gear it's hunting can't hunt it back.
What it catches
- Drones, in full. ASTM F3411 Remote ID over Bluetooth, Wi-Fi beacon and Wi-Fi NAN: ID, altitude, speed, heading, and the pilot's position. Often before you hear the props.
- Trackers. Apple Find My, Google, Samsung and Tile. When someone floods the area with fakes, you get a handful of beeps, one row that says what's going on, and then quiet.
- Surveillance hardware. Flock Safety gear when it's talking, Axon body cams, smart glasses. Axon, Flock, ShotSpotter, Genetec, WatchGuard Video and Digital Ally addresses beep on sight: nobody but an agency buys that.
- Attack gear (opt-in). Deauth bursts, Pineapple-style karma, BLE popup spam, Flipper Zero hints, pwnagotchis by name.
- Whatever you add. The signature list is editable from the app: OUI, company ID, name, service UUID or SSID. No recompile.
Built for the field
- Runs headless. Battery bank or car USB. It scans and beeps with nothing connected.
- Survives the plug-pull. Mute, categories, hunt target, filter, name and rules all come back after a power cut.
- Both bands. The C5 sweeps 2.4 and 5 GHz. Every Wi-Fi row shows its band and channel, and a dual-band router is one row, not four.
- Site Survey. Capture the raw air next to something suspicious, read its signature, photograph it, and export it for DeFlock.
- Logs if you ask. What it beeped at and when, on its own flash or an SD card. Off by default. Never where. Pull it off with the export page; the card never leaves the case.
What it won't do
The only winning move is not to transmit.
- No jamming, no deauth, no packet injection.
- No advertisement spoofing. The
ble_spoofprimitive was cut. - No arbitrary GATT writes. Ringing a tracker is one fixed Immediate Alert write, with a MAC as its only parameter.
- No cloud, no telemetry, no analytics, no account.
It keeps no trail. The app shows what's here right now and forgets it on disconnect. Vendor names are looked up offline, so no MAC leaves your phone. The one location it ever keeps is a pin you say yes to, one device at a time, AES-GCM encrypted behind a PIN, and detecting and beeping never ask for it.
Receive-only stops it advertising SignalSweep to every scanner in
range, including the hardware it is hunting. It keeps listening and beeping.
Straight answers
- Every Flock camera? No. It catches Flock gear when it's talking. A deployed camera on LTE with its Wi-Fi off says nothing to anyone, and nothing can hear that.
- An AirTag right beside its owner? Not flagged. It sends the short form every iPhone sends, and treating those as AirTags is how a corner store reads as 22 trackers.
- Legal? It's a receiver. It transmits a Bluetooth advert you can switch off, the scan requests that ask devices their names, and one write when you press Ring. Know your local law.
Get the hardware
One Seeed Studio XIAO ESP32-C5 (hears 2.4 and 5 GHz) or ESP32-S3 (about $15, 2.4 GHz only). Add a U.FL antenna, a buzzer, a WS2812 LED bar and a microSD reader for the full build. See WIRING.md. On the C5, use a dual-band antenna so it hears 5 GHz as well as 2.4.
Or skip the parts run: kits and built units at signalsweep.net.
Standing on other people's work
SignalSweep exists because of Colonel Panic's OUI Spy, and everything it knows about Flock Safety hardware comes from the OUI research of OrdoOuroborous / @NitekryDPaul. The full list is in CREDITS.md. Read it, then go read their repos.