It's now fairly common to see TV shows directing us to websites for more information, or telling us what number to text in order to cast a vote. A group of Korean entrepreneurs, however, are looking to make such processes even simpler. Their Soundlly system transmits an inaudible ultrasound tone along with TV broadcasts, which allows users' mobile devices to serve as interactive "second screens."

The idea is that Soundlly tech will be built into apps that will run in the background on users' smartphones or tablets. When those people are watching a Soundlly-enabled program, ultrasound pulses embedded in that show will be emitted by their TV's speakers and picked up by their device's microphone.

From there a number of things could happen, depending on the app being used.

Their device might be directed to a relevant website, for example, or to an online voting interface. The technology could also be used to let users buy featured products, get digital coupons, play games that are associated with the programming, or simply receive extra information on the show – sort of like the existing video "pop-ups."

Additionally, the company states that the tones are of a low enough intensity that they shouldn't be irritating to animals or small children.

The system is demonstrated in the video below.

Source: Soundlly via New Scientist