Magnetometer Sensor; Main Features - Nokia NPL-4 Series Manual

NPL-4/5/RM-104
System Module and User Interface

Magnetometer Sensor

The magnetometer will be implemented with anisotropic magnetoresistive (AMR) mag-
netometer component. Two-axis linear magnetic sensors are designed as a Wheatstone
bridges formed by a magnetoresistive metal film. Sensor acts as resistor which resistance
depends on magnetic field strength and direction. This bridge element is capable of
sensing fields in milligauss range.
In order to achieve the measurement resolution, a magnetic pulse must frequently reset
the sensor. Eliminating and compensating external disturbances will be done via coil
strip near of sensor elements with current pulse.
Offset coil strap is used for production level testing and self-testing.

Main features

• Two magnetometer channel blocks (containing X- and Y-axes).
• Set / Reset coil element
• Offset strap coil
Copyright © 2005 Nokia Corporation. All rights reserved.
Page 48
-Measurement with 4-element Wheastone bridge /axes
-Convert magnetic earth field X and Y components to differential outputs
-Current pulse to coil for set and reset sensor
-For testing purposes
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Issue 2 05/05