What a Bluetooth scan will find
Anything using Bluetooth Low Energy and currently powered: speakers, headphones, trackers, smart plugs and bulbs, wearables, some cameras and doorbells, laptops, phones and tablets.
It reports the advertised name, the signal strength, and, where the device broadcasts it, the battery level. Signal strength is what lets you narrow down a location within a room.
What it will not find
Wi-Fi-only cameras. A large share of hidden cameras use Wi-Fi rather than Bluetooth, and a Bluetooth scan is blind to them entirely.
Wired devices with no radio at all.
Devices that are powered off, and devices in a deep sleep that are not currently advertising.
Anything using a proprietary radio protocol, which includes many alarm sensors and most car key fobs.
How to sweep a room properly
Start in the centre and note everything the scan returns. Then walk the perimeter slowly, watching which signals strengthen, that tells you which wall or corner each device is near.
Account for what you can see. Television, soundbar, thermostat, smart bulbs, the router. Cross them off.
Whatever is left with a strong signal and no visible source is worth investigating: check smoke detectors, sockets, clocks, air purifiers, plug adapters and anything positioned to face a bed.
Repeat from the corridor. A device that reads strongly inside the room and weakly outside it is inside the room.
Pair it with other checks
Turn the lights off and sweep with a torch held at eye level, camera lenses retro-reflect and produce a small bright point.
Check the Wi-Fi network for unexpected clients if you have access to the router.
If you find something you believe is a covert camera in accommodation, do not remove it. Photograph it, leave the room, and contact the police.
More on identifying devices
The rest of the material on working out what is broadcasting around you.
- Reading Bluetooth signal strength (RSSI), Reference
- An unknown Bluetooth device is showing up. What is it?, Identify
- “Unknown Accessory Detected” on iPhone: what it means, iOS alerts
- See battery on nearby devices, Inside Scan
- How to find a misplaced baby monitor unit, 8 to 20 hours on the parent unit
- Bluetooth hub, the complete list
Common questions
Can a Bluetooth scanner find hidden cameras?
Only cameras that use Bluetooth and are currently broadcasting. Many hidden cameras use Wi-Fi or record to a local card with no radio at all, and those are invisible to any Bluetooth scan. Treat it as one check among several.
How long should a sweep take?
Give the scan at least a minute in each position. Low-power devices advertise infrequently to save battery and may not appear in the first few seconds.
In the app: The scan shows every nearby device with its name, battery and live signal strength. Read about Bluetooth Scanner.