What Clearsweep cannot find

This is the whole list, gathered from the same file the app reads when it prints the limits next to your result. None of these are things we have not got around to. They are limits of the sensors and the protocols, and they would be true of any app using them.

• A camera on a different network, including one on its own hidden Wi-Fi
• A camera on a mobile data connection, which never touches this network
• An analogue or wired camera, which is not a network device at all
• A camera that records to a memory card and never connects to anything
• Anything at all if this device is not joined to the network being swept
• Devices that are silent: a device that answers nothing is not in the list
• A camera that streams only to its maker's cloud and listens to nothing locally
• What a device on the Tuya platform is: many low-cost Wi-Fi cameras use it, and the network cannot tell a plug from a camera
• A Tuya-platform device whose announcements this device never hears, for example because a firewall blocks incoming broadcasts: Windows did that on the studio's desktop while macOS and Linux heard the same device
• On a phone, any device's maker when the device did not say it: Android does not let apps read hardware addresses
• A tracker that is not advertising right now, including one still near its owner
• A GPS tracker that reports over mobile data and uses no Bluetooth
• A tracker whose battery is dead, which is still evidence but not a signal
• A tracker inside metal or heavy shielding
• A tracker that is not magnetically mounted, such as one wired into the car
• A tracker plugged into the car's diagnostic port
• Anything further away than roughly a hand's width from the phone
• Any camera that is not using infrared, which is most of them in daylight
• A camera whose infrared is off because the room is lit
• Anything, on phones whose camera filters infrared out; test yours with a TV remote first
• A lens behind glass, fabric, or a one-way mirror
• A lens pointed somewhere else
• Anything in a bright room, where the reflection does not stand out
• Whether anyone else on this network knows the password, which at a hotel is every guest
• A fake network with the same name as the real one
• What happens to your traffic after it leaves the router
• The mode of any network this device is not joined to
• Whether the sign-in page is the hotel's or a copy of it
• What the network does after you sign in
• A network that blocks the test address for another reason
• A hijack of names this check did not ask for
• A hijack that only happens on some pages
• A network that answers honestly now and not later
• Anything the DNS answer does not touch, such as traffic redirected after the lookup
• Differences that are innocent: content delivery networks answer differently by place and time
• Whether the admin page accepts the factory password: this check never tries one
• Admin pages on other ports or on the router's other address
• Anything on the internet side of the router
• Hosts that exist but do not answer the ports tried
• Isolation that blocks some traffic and not other
• Devices on a separate network or VLAN, which can never be seen from here
• Whether the firmware is old: an open port does not say
• Whether UPnP has already opened a hole to the internet: that cannot be seen from inside the network
• Devices that use the cloud only and say nothing locally
• Anything not on this Wi-Fi
• A spoof that starts after the check ends
• A spoofer that copies the router's address exactly
• Normal setups where one device has several addresses
• Anything on a phone: Android does not let apps read this table

What that adds up to

A camera that records to a memory card, plugged into a socket behind a mirror, using no network and no Bluetooth, is invisible to every check on this page. So is a tracker wired into a car's electrics. If your reason to worry is strong, a phone is a first pass and not an answer — a physical search of the sockets, smoke detectors and vents, or a professional sweep, is what comes next.

Per check