Printed Sensor Monitors Tire Tread in Real Time
A flexible, printed sensor that accurately measures tire wear in real time could warn drivers when the tread on their tires has gotten uneven or precariously thin. The sensor, made with carbon nanotube ink, spots millimeter-level changes in tire tread with 99 percent accuracy.
Today’s cars are laden with sensors that keep tabs on many variables including engine temperature and fuel pressure as well as environmental conditions and approaching obstacles. But there is no technology to monitor tire wear, says Duke University professor of electrical and computer engineering Aaron Franklin, who led the team that reported the new tire sensor in IEEE Sensors Journal last year.
The researchers’ spinout Tyrata, Inc. raised US $4.5 million from several investors last week. Franklin says the startup should have a sensor package that’s ready to go into cars by mid-2019. “The device is so simple and the need is so great since no existing competitor is available, that response from the industry has been astonishing,” he says.
The new tire sensor is simple: it consists of just two millimeter-scale electrodes that the researchers print on a plastic substrate using carbon nanotube ink. The device goes on the inside wall of a tire. An oscillating voltage is applied to one electrode and the other is grounded to create an electric field, part of which arcs over the electrodes and passes through the tire rubber. The sensor system measures the magnitude of the oscillating signal reflecting off the grounded electrode, which changes with slight changes in the rubber’s thickness.