You may be interested in the Wi Fi locator devices, of which there are many on the market.
Basically, they tell you if you are near an access point and sometimes even details, such as SSID and whether it is open or secured. If you move around a lot, especially on city streets, it saves you the trouble of having to pull out your laptop to see whether you might get a connection.
The
smallest fit on a keychain and the
fully featured ones are still smaller than a cellphone.
