Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetic sensor that brooks no interference

04.06.2008
A novel magnetic sensor for the first time detects tiny fluctuations in a small magnetic field – even when there is a strong magnet right beside it. The sensor can thus be utilized even in places where power cables generate an interference field – for instance in a car’s side mirror.

Sensors accurately register the slightest temperature fluctuations, the tiniest changes to a magnetic field, or barely perceptible air currents. In some cases, however, there are limits to their accuracy – for instance when a sensor is supposed to register a small fluctuation to a magnetic field in a place where a strong magnetic field already exists.

Take the sensors in a car mirror: If there is a change of driver, the seat and the mirror usually have to be re-adjusted. It would be easier if the position of the seat and the mirror could be saved individually for each driver. With the aid of a tiny chip in the key or a corresponding button on the dashboard, the driver can move these into the correct position at the press of a single button.

There is a tiny magnet in the mirror and another in the seat, whose position is detected by a magnetic sensor and which enables the mirror to be correctly adjusted. The only problem with this system is that the cables which supply the power for heating the mirror and controlling the stepper motor also generate a magnetic field. The sensor therefore sees not only the field generated by the magnet, but also that of the power cable – and comes to the wrong conclusions. Up to now, therefore, such magnetic field sensors have had to be screened. This is difficult and expensive.

A new type of integrated 3-D magnetic field sensor from the Fraunhofer Institute for Integrated Circuits IIS in Erlangen can work without screening. The researchers have arranged several sensors in a pixel cell in such a way that they can measure all three components of the magnetic field in one place. If two of these pixel cells are placed on a chip, the sensor measures not only the magnetic field as such, but also how the position of the magnetic field changes. “This sensor enables us for the first time to identify magnetic interference fields as such and to separate them from the useful field. The sensor works perfectly even when the interference field is considerably larger than the useful field,” says IIS team leader Dr. Hans-Peter Hohe. “There is therefore no need for shielding.”

The sensors have another advantage, too: They are suitable for high-temperature applications up to around 150°C and can therefore be utilized in places such as the engine compartment. The sensors have already been tested and developed to a stage where they are suitable for industrial use. To facilitate serial production of the sensors, the researchers used low-cost standard CMOS techniques to manufacture them.

Press Office | alfa
Further information:
http://www.fraunhofer.de/EN
http://www.fraunhofer.de/EN/bigimg/2008/rn06fo2g.jsp

More articles from Automotive Engineering:

nachricht When your car knows how you feel
20.12.2017 | FZI Forschungszentrum Informatik am Karlsruher Institut für Technologie

nachricht Did you know how many parts of your car require infrared heat?
23.10.2017 | Heraeus Noblelight GmbH

All articles from Automotive Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>