There are already plenty of ways of taking hands-free phone calls, although most of those involve wearing some sort of earpiece. Not everyone enjoys having something continuously stuck in their ear, however, plus such devices lessen the user's ability to hear other sounds through that ear. Buhel's SG05 SoundGlasses take a different approach. They relay sound to the user via bone conduction, leaving their ears open to hear the world around them.
SoundGlasses communicate with the user's iOS, Android or Windows smartphone via Bluetooth 4.0. Phone call audio (or music from the mobile device's library, or from a Bluetooth-enabled MP3 player) is played back through two transducers, one located in each arm of the glasses. As with other bone conduction devices, the vibrations from those transducers travel through the bone in the sides of the user's skull to their inner ear, where they're heard as sound.
Not only does this leave the ear canal open to hear other sounds such as oncoming traffic, but it also allows for the use of hearing protection in overly-noisy environments.
Users hold up their end of the conversation using a bidirectional noise-canceling mic in the bridge of the sunglasses, plus a multi-function button can be utilized to place and end calls, or to activate Siri/Cortana. One 3-hour charge of the glasses' lithium-ion battery should be good for about three hours of talk time, or around 300 on standby.
SoundGlasses come with multiple interchangeable Category 3 UV-certified lenses, along with an adapter for allowing users to mount their own prescription lenses. Buhel's parent company Atellani is currently raising production funds for the glasses, on Kickstarter. A pledge of US$160 will get you a set, assuming all goes according to plan. The estimated retail price is somewhere over $270.
Buhel, incidentally, already offers ski goggles with similar functionality.
More information on the SoundGlasses is available in the pitch video below.