July 31, 2013 -- Lots of things go into people's mouths -- cigarettes, pens and pencils, piercings and decaf coffee, to name a few. But engineers at National Taiwan University have added a new entry to that list: electronics. The research team, led by Polly Huang and Hao-Hua Chu, has created a motion sensor that can be glued to the teeth to detect a variety of actions the mouth is performing in real time.
Embedded in the chip that measures 4.5 by 10 millimeters are accelerometers that can detect motion in three dimensions. While the current design still needs to be physically wired to a computer, the team is looking to add a wireless data transmitter, giving new meaning to the term "Bluetooth."
In addition to the chip itself, the research team has created a program that can look at the motion data and figure out whether a person is chewing, drinking, speaking or coughing. It does so with 60 percent accuracy, although that score jumps up to 94 percent if the person wearing the sensor provides some test data to the program beforehand.
Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton University, called the team's research exciting but more as a proof of concept than as a specific product. "If you look at smart watches or Google Glass, these are attempts at taking electronics and finding ways to merge it with the body," he told ABC News. "This is where the future is going."
McAlpine's own research also looks at how to put electronics on teeth. Rather than go the traditional silicon chip route, his team designed a circuit using graphene, a 1-atom thick conductive material that is directly applied to a tooth. "It's like applying a temporary tattoo," he said.
Although McAlpine's graphene circuit senses specific molecules in the mouth, McAlpine can see a modified version of the circuit that contains an accelerometer. "People are going through a list of devices one by one," he said. "They're trying to figure out how to get [these devices] to interface directly with the body."
While McAlpine appreciates the work of the National Taiwan University engineers, he also said that they should view their work from a materials engineering point of view. "They are using standard silicon-based chips and components to do this," he said. "But silicon is hard, rigid and brittle. Instead, you want an interface that melds with the body."