Harnessing Chewing Power
Mechanical engineers in Canada have developed a chin strap that can harness the energy from chewing and convert it into electricity that could one day power hearing aids, earpieces and other small devices.
Study co-authors Dr Jeremie Voix and Dr Aidin Delnavaz from Montreal’s École de Technologie Supérieure have previously worked on auditory technology, such as cochlear implants and powered ear-muffs, and wanted to see if they could come up with a way to decrease the reliance on disposable batteries.
The team had gone through every power source they could think of – from harnessing the energy from head movements (like the wrist movements that power automatic watches) to the heat inside the ear canal. They even looked into the tiny movements inside the ear canal caused by jaw activity.
But then they realised that when a person is moving their jaw, the chin actually moves more than the ear canal does. “And if you happen to be wearing some safety gear, then obviously the chin strap could be actually harvesting a lot of energy,” said Dr Voix.
Using this idea, the team created a prototype chin strap made from a ‘smart’ material called PFC (piezoelectric fibre composites), so-called because it goes through a process called the ‘piezoelectric effect’. This is when certain materials acquire an electrical charge when they are squeezed or stretched.
To test out the prototype’s maximum performance, the chin strap was snugly fitted over the user’s chin, so that when the jaw moved, the strap would easily stretch. The user was then asked to chew gum for 60 seconds, with the results published in Smart Materials and Structures.
The prototype only made a small amount of energy and needs to become around 20 times more efficient to make a useful amount of electricity, but the team says that this can be done by simply adding more layers of PFC to the strap.
Dr Delnavaz explained that with the price and short lifespan of , hearing aids powered with a PFC chin strap could start saving the user money after only three years of use. Having a renewable power source would also decrease the impact of disposable batteries on the environment.
“We will now look at ways to increase the number of piezoelectric elements in the chin strap to supply the power that small electronic devices demand,” he added. “And also develop an appropriate power management circuit so that a tiny, rechargeable battery can be integrated into the device.”
Charging something as big as a mobile phone using a device like the chin strap is a very long way off just yet, but chatting away on one could easily be adapted into charging a Bluetooth headset or something similar. This is definitely something to keep an eye out for!