Signal Watch Guard

Signal Watch Guard listens for the Bluetooth Low Energy signals that nearby devices broadcast, and alerts you when a device you care about is close by. It's a simple, private radar for the wireless world around you — no account, no sign-in, and nothing ever leaves your iPhone.

WATCHLIST ALERTS
Add the devices you want to know about and get a notification the moment one appears nearby. You're alerted once when a device shows up; while it stays around it keeps showing in Detections without nagging you again, and if it leaves and comes back you're alerted again. Comes preloaded with signatures for popular smart glasses and a few well-known camera and body-worn devices — edit, disable, or delete any of them.

SEE EVERYTHING NEARBY
The Scan tab lists every Bluetooth advertiser it hears, with maker names resolved from the built-in Bluetooth database, service IDs, and live signal strength. Tap any device to inspect its decoded fields and raw advertisement data, and add it to your watchlist in one tap.

PRECISE, ALL-FIELDS MATCHING
A watchlist item matches only when every detail you specify matches — maker ID, name, service ID, or manufacturer data — so you get the device you meant, not everything from the same maker. Want broader coverage? Add separate items.

SIGHTINGS LOG
Every alert is logged with the date, time, signal, and the full details collected from that device, so you can review it later. Turn on optional location to save an approximate spot with each sighting and open it in Apple Maps or Google Maps. Group by day, search, and export or import the whole log as CSV.

MADE FOR PRIVACY
• All scanning and matching happen on your device.
• No analytics, no accounts, no data collection.
• Nothing is ever uploaded or shared.

CHOOSE HOW YOU READ SIGNALS
Show signal strength in dBm, or a rough distance estimate in meters or feet.

GOOD TO KNOW
Signal Watch Guard only sees devices that broadcast Bluetooth Low Energy advertisements. Apple doesn't expose a device's permanent identifier, and many devices rotate their Bluetooth address over time, so repeat-detection and "ignore" aren't perfect. Devices broadcast most when turning on, pairing, or opening their case, and can go quiet in between. Distance is an estimate only — walls, bodies, and orientation all affect it.