A chin strap that can harvest energy from jaw movements can be used to power small electronic devices, researchers have said.

The strap is made using piezoelectric fiber composites (PFC). Chewing meals alone can generate around 7 mW of power. The device harvests energy from talking, chewing and eating, and power devices such as hearing aids, cochlear implants and cellular phones.

The researchers said that the chin strap is still in its developmental stages but, it shows that piezoelectric materials can be used to replace conventional batteries, at least to some extent.

Common batteries aren't just expensive to produce but, are also harmful to the environment. Our dependency on these portable power sources can be reduced if researchers find a way to use piezoelectric material to power wearbale electronic devices.

Piezoelectric materials produce electric charge when subjected to mechanical stress. The latest device has PFC, which is a type of piezoelectric smart material and has integrated electrodes and an adhesive polymer matrix.

In their study, the researchers created an energy harvesting chin strap made from a single layer of PFC and attached it to a pair of ear muffs using a pair of elastic side straps. To ensure maximum performance, the chin strap was fitted snugly to the user; so when the user's jaw moved, it caused the strap to stretch.

The chin strap has a single layer of PFC, which is attached to a pair of ear muffs using elastic side straps.

To test the strap, the user was asked to chew for about 60 seconds while wearing the head gear. The team found that the maximum amount of power that can be generated from jaw movements is around 18 µW. However, in real-world scenario, the output is about 10 µW.

"Given that the average power available from chewing is around 7 mW, we still have a long way to go before we perfect the performance of the device," Aidin Delnavaz, co-author of the study, said in a news release.

"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 chin strap. For example, 20 PFC layers, with a total thickness of 6 mm, would be able to power a 200 µW intelligent hearing protector," Delnavaz said in a news release.

Scientists at Sonomax-ÉTS Industrial Research Chair in In-ear Technologies (CRITIAS) at École de technologie supérieure (ÉTS) in Montreal, Canada, conducted the study and it is published in the journal Smart Materials and Structures.