An inexpensive printed sensor that can monitor the tread of car tyres in real time has been invented by electrical engineers at Duke University in collaboration with Fetch Automotive Design Group. If adopted, the device could increase safety, improve vehicle performance and reduce fuel consumption.
"With all of the technology and sensors that are in today's cars, it's crazy to think that there's almost no data being gathered from the only part of the vehicle that is actually touching the road," said associate professor Aaron Franklin.
The design uses metallic carbon nanotubes on a flexible polyimide film that could track millimetre-scale changes in tread depth with 99% accuracy.
The core of the sensor is formed by placing two electrodes very close to each other. By applying an oscillating electrical voltage to one and grounding the other, an electric field forms between the electrodes.
While most of this electric field passes directly between the two electrodes, some of the field arcs between them. When a material is placed on top of the electrodes, it interferes with this field. By measuring this interference through the electrical response of the grounded electrode, it is possible to determine the thickness of the material covering the sensor.
The sensors could be printed on most anything using an aerosol jet printer – even on the inside of the tyres themselves.
Franklin's group also wants to explore other automotive applications for the printed sensors, such as keeping tabs on the thickness of brake pads or the air pressure within tyres.
"This setup could be used with just about anything that isn't metallic or too thick," said Franklin. "Right now we're focusing on tyres, but really anything you'd rather not have to cut apart to determine its thickness could be monitored by this technology in real time."