Sensor that creates its own energy could be useful for automotive

Self-power sensors use the changing shape of nanowire to impart strain on a piezoelectric material
Self-power sensors use the changing shape of nanowire to impart strain on a piezoelectric material (Bing)

Sensors have long been important for the functioning of vehicles, and they are expected to become even more critical as vehicle technologies continue to advance. Now, researchers at the University of Florida Herbert Wertheim College of Engineering have created a new kind of sensor that creates energy and, therefore, wouldn't need to take any from a car's battery, extending its life.

Modern cars come with a wide range of sensors. They enhance safety by alerting drivers to things like doors that are open and unfastened seatbelts. They can also help provide information about tire pressure and engine revolutions per minute (RPMs). Some cars also have sensors that alert a driver if he’s going to bump into something as he backs up.

Sensors also power the semi-autonomous features available on some modern vehicles, such as automatic parallel parking. As vehicles continue to integrate more autonomous features, these sensors will become even more crucial.

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Autonomous vehicles use a system of sensors and an onboard computer to map the surrounding environment and then use that information to steer through ever-changing situations that include other vehicles, pedestrians, traffic signals, weather conditions and hazards in the roadway.

Revenue for the automotive imaging technology is expected to grow at compound annual growth rate (CAGR) of 20% between 2015 and 2021 to $7.3 billion, demonstrating how much the number of sensors that vehicles have will grow in the coming years.

Sensors that create electricity

All of these sensors, though, require electricity. They take just a small amount of energy from the vehicle's battery, but eventually, all that energy adds up, especially as the number of sensors increases. With the rise of electric vehicles, electricity is now also used to power vehicles themselves rather than just their electronic features. With electric vehicles, any electricity that the car uses for sensors can't be used for directly powering the vehicle.

A recent innovation from researchers at the University of Florida Herbert Wertheim College of Engineering could help to address this battery depletion issue. The engineers developed a new kind of sensor that creates energy rather than taking energy from a car's battery. The sensors could also be smaller than existing sensors and require less energy.

The team engineered a "composite magneto-electric nanowire array sensor" that uses electrical impulses created by the changing properties of the nanowire to monitor automobile operation.

Each nanowire consists of two halves. The researchers paired barium titanate, which has piezoelectric properties, with cobalt ferrite, which is a magnetostrictive material.

When there is a magnetic field, such as the one that exists in the steel gears of a car engine, a shape change occurs in the cobalt ferrite. The cobalt ferrite imparts a strain to the barium titanate, inducing an electrical polarization. Linking the nanowire to a data-gathering source enables the electrical impulses to be used to sense things like engine timing or a skidding tire. Connecting numerous nanowires in parallel creates a functional magnetic field.

The research team noted that their nanowires displayed significantly stronger magneto-electric coefficients than traditional magneto-electric material, which indicates that they generated stronger electrical impulses. This improved performance means the sensors could be smaller while still providing the same amount of power.

Applications outside of automotive

The sensors could also have applications outside of the automotive sector. Many different industries use sensors. For example, the aviation sector use the sensors in similar ways as the automotive industry. As more sectors begin to use automated equipment, these kinds of sensors will become increasingly seen across many industries.

Manufacturing, for instance, could use them for robotic equipment. The increasing prominence of the internet of things will also contribute to increased demand for sensors, as many IoT devices rely on them. The fact that the newly-developed sensors require no external energy source and can be relatively small make them potentially valuable for many different applications across numerous sectors.

The UF Office of Technology and Licensing obtained a provisional patent on the sensor technology and filed for a U.S. utility patent. Allegro Microsystems, a global power and sensing semiconductor company, licensed the patent.

Professors Dr. Jennifer Andrew and Dr. David Arnold, along with Matthew Bauer, Xiao Wen and Prabal Tiwari, published their research findings in a paper titled "Magnetic field sensors using arrays of electrospun magnetoelectric Janus nanowires" in the December issue of Nature’s online publication Microsystems and Nanoengineering.

Modern vehicles incorporate a wide range of sensors, and as vehicles become more autonomous, they will require even more of them. All of these sensors require energy to function, and the growing popularity of electric vehicles means that electricity will become more important for vehicles' operation.

Because this sensor creates its own energy, it could help to enable the future of the automotive sector and increasing the efficiency and safety of the vehicles of tomorrow.

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