WiFi signal detectors are very handy devices which allow you to check on the Wi0fi signal status around you with out having to fire up the laptop. This saves time because wi-fi isn't always available. WiFi detectors can be found on t-shirts, watches and on specific products to do just that. The latest is a pair of Wi-Fi detecting trainers (sneakers).
The Wifi detection unit is installed under the flap of the left shoe. Three LED's then indicate to the wearer the strength of the signal. The detector trainers will pick up signals up to 50 meters away which makes them a very handy bit of kit. The detector only activates when you are wearing the shoe by using some pressure sensors inside the shoe.
Via: TechChee