In a development that could bring new meaning to the term "motor mouth," Canadian researchers have developed a chin strap capable of generating electricity from jaw movements. The team is hopeful that the strap will be able to harvest energy from common actions like eating, chewing and talking to power medical implants and wearable devices.

Based at Montreal's Sonomax-ÉTS Industrial Research Chair in In-ear Technologies (CRITIAS) at École de technologie supérieure, the researchers were looking into the potential of jaw movements as a means of generating power. The jaw has been recognized as one of the body parts with the most potential in this area, with estimates that the act of chewing during mealtime, for example, could produce around 7 mW of power.

In an attempt to avoid all of that munching from going to waste, the team built a specialized chinstrap made from piezoelectric fiber composites (PFCs). This piezoelectric material comprises integrated electrodes and an adhesive polymer mix and is subject to mechanical stress as it stretches, resulting in an electric charge.

So how much charge are we talking exactly? Well, don't go ditching your phone chargers just yet. In testing where a subject chewed gum for 60 seconds, the strap's power output was around 10 µW, (out of a theoretical maximum of 18 µW). Research suggests it takes between 400,000 and 1,000,000 µW to make a phone call.

Exploring the possibilities of kinetic energy has turned up some interesting results of late. From pedal-powered work stations to percussion instruments that double as mini-generators, there's something quite alluring about physical exertion driving more than just our body's movements.

Basic and functional, but not exactly inconspicuous, the piezoelectric chinstrap is still a ways off becoming a viable product. The researchers do describe it more as a proof of concept rather than a device they actually expect people to wear, but they hope advances in this area could help wean us off expensive batteries that can be harmful to the environment.

"The power level we achieved is hardly sufficient for powering electrical devices at the moment; however, we can multiply the power output by adding more PFC layers to the chinstrap," says Aidin Delnavaz, one of the study's co-authors. "For example, 20 PFC layers, with a total thickness of 6 mm, would be able to power a 200 µW intelligent hearing protector.”

The team will now turn its attention to increasing the amount of piezoelectric elements in the strap to improve its energy harvesting capacity. It is hoped they can then use it to power small electronic devices and integrate a rechargeable battery for power management.

The research paper was published in the journal Smart Materials and Structures.