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 Improved Performance thanks to Reduced Weight
24.07.2017 | Technische Universität Chemnitz

nachricht New Headlamp Dimension: Fully Adaptive Light Distribution in Real Time
29.06.2017 | Universität Stuttgart

All articles from Automotive Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Molecular volume control

22.08.2017 | Life Sciences

When fish swim in the holodeck

22.08.2017 | Life Sciences

Biochemical 'fingerprints' reveal diabetes progression

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>