How can magnetic sensing control the flight of a drone?

At Sensor Expo 2017, Ali Alaoui, a field applications engineer from Crocus Technology, explains the use of his company’s Tunneling MagnetoResistance (TMR) sensing technology to control the flight of a drone. Crocus Technology’s patented TMR sensing technique employs a Magnetic Logic Unit (MLU) that enables ultra-sensitive magnetic sensors as well as highly robust secure embedded memory and ultra-high-temperature non-volatile memory (NVM) capable of operation above 200°C.

The CT300 discrete TMR angular sensor used in the demo has an operating temperature of -40 to 125°C. Detecting the absolute angular orientation of an on-axis 2-pole magnet rotating over the center of the sensor, the angular sensors will provide two, independent sinusoidal output signals 90° out of phase.

In robotics and factory automation, magnetic sensors are used for linear and angular position sensing to implement complex motor movements as well as for linear and angular sensing, safety switches, and proximity detection.

In white goods, the magnetic sensing technique provides added intelligence for open/close door detection, fluid level, and contactless current sensing.

In the demo at Sensors Expo, the TMR field sensor provides two-axis control of a drone. Housed in a quad surface mount (QSM) (also called a quad flat no lead (QFN)) package, the two-axis field sensor gets input from magnets all pointed in the same direction through a plexiglass dome. The control modifies the field that the two-axis sensor measures. The field is maximum at one point and minimum 90-degrees from the rotational point.


  1. Charles Linquist says:

    I’m curious as to what this really means. Virtually all drones use magnetometers to both sense absolute direction and to zero out the drift in their on-board gyroscopes. So all high-performance drones already use magnetometers for direction control.

    What is the purpose of this new application? Is it more sensitive than the current magnetometers used?

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