Researchers in Canada developed a chin strap that can harvest energy from the movement of your jaw. The researchers are hoping the device can generate enough electricity from eating, chewing and talking to power a number of small devices including hearing aids, electronic hearing protectors and communication devices.
The initial results of the device’s performance were published last month in IOP Publishing’s journal Smart Materials and Structures.
The movement of a person’s jaw was proven to be one of the most promising candidates for generating electricity from human body movements, with researchers estimating that an average of around 7mW of power could be generated from chewing during meals alone.
To harvest this energy, the researchers, from Sonomax-ÉTS Industrial Research Chair in In-ear Technologies (CRITIAS) at École de technologie supérieure (ÉTS) in Montreal, Canada, created a chin strap made from piezoelectric fiber composites (PFC).
PFC is a type of piezoelectric smart material that consists of integrated electrodes and an adhesive polymer matrix. The material is able to produce an electric charge when it stretches and is subjected to mechanical stress.
Aidin Delnavaz, the co-author of the study, said “Given that the average power available from chewing is around 7mW, we still have a long way to go before we perfect the performance of the device.”
“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 6mm, would be able to power a 200 µW intelligent hearing protector.”
One of the main motivating factors for pursuing this area of research is the desire to curb the current dependency on batteries, which are not only expensive to replace but also extremely damaging to the environment if they are not disposed of properly.
“The only expensive part of the energy harvesting device is the single PFC layer, which cost around $20. Considering the price and short lifetime of batteries, we estimate that a self-powered hearing protector based on the proposed chin strap energy harvesting device will start to pay back the investment after three years of use,” continued Delnavaz.
“Additionally, the device could substantially decrease the environmental impact of batteries and bring more comfort to users.
“We will look at ways to increase the number of piezoelectric elements in the chin strap to supply the power that small electronic devices demand, and also develop an appropriate power management circuit so that a tiny, rechargeable battery can be integrated into the device.”