March 22, 2006
Asahi Kasei EMD Corporation
Asahi Kasei Microsystems Co., Ltd.

World's smallest and thinnest 6-axis electronic compass
- combination of 3-axis geomagnetic sensor with 3-axis acceleration sensor -

 
Asahi Kasei Microsystems (AKM), wholly owned subsidiary of Asahi Kasei EMD, will begin sample shipments of the AK8976A, the world’s smallest and thinnest 6-axis electronic compass. The new device and example applications will be on display at Sensor Expo Japan from April 5 to 7 in Tokyo.

The 6-axis electronic compass is an extension of the development work which resulted in the AK8970 and AK8970N, AKM’s 3-axis electronic compass products sold since 2003. These were the world’s first 3-axis electronic compass products designed specifically for cell phone use, and have been incorporated in many handsets in Japan and around the world. The 3-axis products overcame the shortcomings of the then-available 2-axis electronic compasses through the use of Asahi Kasei EMD’s Dynamic Offset Estimation™ (DOE™) algorithm to automatically compensate for fluctuations of magnetic offset.

While superior to competing products, the 3-axis electronic compasses performed best when the cell phone handset was tilted at a particular angle. Accurate compass performance regardless of handset orientation could be obtained by including acceleration sensors in handset designs, but such additional complexity is not generally desired. The new 6-axis electronic compass provides the ideal solution, combining a 3-axis geomagnetic sensor with a 3-axis acceleration sensor in an ultra-small package.

In a GPS-enabled cell phone, this not only enables a pedestrian navigation system to accurately align a 2D map with the direction of forward progress without requiring the user to hold the handset at a particular angle, but also makes a whole new range of services possible, including 3D maps continuously aligned to the display angle and even access to menus of real-time information such as a schedule of events or a list of shops simply by pointing the handset at a building. See www.s3sensor.com/en/s3/future01.html for more information, including virtual demonstrations.

The AK8976A also features dedicated hardware for pedometer and free-fall detection functions, enabling full-time operation with the handset in low-power mode with only 100 µA, less than one tenth the current consumption of conventional solutions which require the host CPU.

In addition to DOE™ adjustment for the 3-axis geomagnetic sensor, the AK8976A automatically adjusts for offset and sensitivity of the 3-axis acceleration sensor. This enables greatly improved productivity by eliminating the need for these adjustments to be performed individually for each chip before shipment.

Other features and specifications include:
  Hall-effect geomagnetic sensor in three axes, piezoresistive accelerometer in three axes
  Digital interface with internal A/D converter compatible with both 2-line I2C bus and 4-line SPI
  Low power consumption – 6.7 mA during sensor operation, 460 µA average with measurement at 100 ms intervals
  Internal temperature sensor with 8-bit digital output
  Internal 8-bit, 12-word EEPROM for recording geomagnetic sensor sensitivity adjustment data, etc.
  4.5 mm × 4.5 mm × 0.9 mm (1.0 mm max) 20-pin LCC package

Applications foreseen include pedestrian navigation systems on cell phones and PDAs; motion input controllers for videogames; and measurement of direction/tilt angle information, portrait/landscape mode changeover, and camera-shake warning systems in digital still cameras and other portable devices.


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