Rotation angle and stroke detection in a

limited space for sensing

Issue #01

SOLUTIONS

Issue ...

Detecting rotation angle and stroke with effective use of space

For rotation angle and stroke (distance) detection, the "optical sensor" and "Hall sensor" configurations are often used. However, when using an optical sensor, there are restrictions on the arrangement due to the position between one LED (light source), lens, and light-receiving sensor each. And also when using a Hall sensor, the arrangement of the magnet and sensor is limited because the sensor's magnetic surface is unidirectional.

Solution ...

"Tri-axis Magnetic Sensor" with higher flexible placement

AKM's tri-axis magnetic sensors sense magnetic fields in three axial directions (X, Y, and Z) in a compact single package and output them as 3D magnetic data. With a simple configuration that combines this tri-axis magnetic sensor with a 2-pole magnet, rotation angles and stroke amounts can be detected from 3D magnetic data.

Additionally, tri-axis magnetic sensor can sense the magnetic field of magnets in various directions when viewed from the sensor, so that it can detect the rotation angle and stroke in a flexible placement.

In other words, it is possible for customers to determine the arrangement of sensors and magnets with a higher flexibility of placement, allowing for a layout that makes more effective use of the limited space.

The following shows an example of arrangement of rotation angle detection and stroke detection.

◆ For rotation angle detection

Schematic diagram of an optical sensor

Depending on the position between the LED, lens, and light-receiving sensor, the arrangement is decided.

Schematic diagram of a tri-axis magnetic sensor

Position of the sensor under the magnet
Position of the sensor beside the magnet
Position of the sensor at the tip of the shaft

◆ For stroke detection

Schematic diagram of an optical sensor

Depending on the positional relationship between the LED, lens, and light-receiving sensor, the arrangement is decided.

Schematic diagram of a tri-axis magnetic sensor

Position of the sensor under the magnet
Position of the sensor beside the magnet

Tri-axis magnetic sensor enables a higher flexibility of placement than optical sensors and Hall sensors.

"Demo kit video for Rotation/Stroke/Push/Pull Detection"  show  the detailed content, such as  magnet material, magnet size, and distance to the sensor. 

AKM offers an evaluation kit with sensors and microcomputers used in this demo kit video.

AKM offers a lineup of AK09970N/D using two types of small packages, QFN (3mm x 3mm) and WLCSP (1.35mm x 1.35mm), which are ideal for those who want to "effectively utilize a limited placement space to detect rotation angles and strokes," contributing to the improvement of flexible placement. (Here is the product lineup)