The other day, during Google’s I/O conference keynote, the company announced a new feature for Chromecast users, namely the fact that owners would be able to avoid giving their WiFi password to everyone.
This means that anyone that comes into your home can cast content to the TV after you allow support for nearby devices. But since Chromecast is a WiFi-based device, how is that even possible if you don’t grant that individual access to the wireless network?
Well, it looks like they connect over inaudible, ultrasonic sounds, which makes sure that your next door neighbors won’t hijack your streaming session. The Chromecast dongle basically plays a unique ultrasonic sound through the speakers of the TV and a mobile device in the same room picks it up and creates the necessary pairing to allow the casting.
You won’t be able to hear the sound, of course, but your mobile device will and that’s what’s important. GigaOm mentions that there will also be a four-digit pin on the TV screen, which should make it possible to manually pair the two devices.
The idea to connect a smartphone to the Chromecast in such a way comes from Google’s Borin Smus, who has already built such an app as an experiment.