Smart glass has become a popular fixture in homes and offices for its ability to change between transparent and opaque, depending on whether an electric current is applied. It's a handy invention, but also tends to be expensive to install and offers only limited control. Sonte is hoping to change that with an affordable window film that connects wirelessly to a smartphone app to instantly turn any section of glass from clear to solid at the press of a button.

Unlike most smart glass kits, Sonte Film is designed for do-it-yourself installation. Rather than replacing an entire window to get the effect, the covering can be sized and cut to fit any existing glass partition. Once it's attached, an electrostatic cling adhesive on the back of the film keeps it stuck to the glass.

Sonte developed its own conductor clip to supply electricity to the film, which is about the size of a coin and which connects to a Wi-Fi-enabled transformer with a slim concealable cord. After the film is in place, users can control its level of opacity from any location using a free iOS or Android app.

Having privacy on command may be the most obvious advantage to covering a window with Sonte Film, but it provides a few additional uses as well. Since the covering blocks UV rays, users can change its transparency to adjust a room's temperature or lighting and conserve energy as a result. In opaque mode, the film is also solid enough to act as a projector screen for a home theater or office.

The system isn't completely perfect however. Even in full transparent mode, the film blocks 30 percent of light from entering and affects the glass' clarity when viewed from an angle. Meanwhile, the most opaque setting still allows five percent of light through. The developers are hoping to develop the film further for a better range of opacity in the future.

The company is currently running a Kickstarter campaign to bring the Sonte Film to market and is offering kits as rewards, which are expected to ship in September. The kits start at US$65 for a 50 x 50 cm (1.6 x 1.6 ft) square and range all the way up to $374 for a 1 x 2 m (3.3 x 6.6 ft) sheet, plus shipping costs. Most include the Wi-Fi-enabled transformer, conducting clip, cables, cleaning kit, and the Sonte Film itself, though kits with simple on/off switches are available as well.

See the video below to see the Sonte Film in action.

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