Specifications

BMA180

Preliminary data sheet

Bosch Sensortec

Rev. 1.0 Page 65 / - proprietary information - 06 March 2009

as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Specifications within this document are preliminary and subject to change without notice. Document is not intended for publication.

9 Application examples

9.1 Wake-up/free-fall detection

Wake-up:

The high-g interrupt feature with an appropriate threshold (e. g. 100 mg) can be used to wake-

up a device without using complex algorithms. Please consult your Bosch Sensortec

representative for more details.

Zero-g/free-fall detection:

The interrupt can also be used for zero-g or free-fall detection. An application note that will

describe this operating mode using the BMA180 in a more detailed way is under preparation.

9.2 Determination of orientations

The sensor is providing very low noise and very small offsets. Thus it is perfectly made to

determine orientations of devices. Some devices require detailed angular information, but

mostly coarse information about an orientation change of the sensor with respect to the

gravitational field vector g is sufficient (black dot = pin 1 identifier). Detailed explanations, etc.

will be given in a separate application note (under preparation).

9.3 Tilt measurements

Due to the very high performance BMA180 is not only usable for tilt compensation in electronic

compass applications. Furthermore high accurate tilt compensation could be performed (level

meters). Detailed considerations will be presented in a separate application note (under

preparation).

9.4 Dead reckoning by double integration

Improvements of GPS systems by inertial navigation require usage of very accurate sensors.

Even if BMA180 provides high resolution and accuracy, a re-calibration at end-of-line testing in

manufacturer production side might be useful.

For dead reckoning applications, especially the following parameters need to be as small as

possible: offset, TCO, sensitivity variation, TCS, non-linearity, noise.

Due to the recalibration possibility of the BMA180 (customer is able to recalibrate sensor at its

production site) almost all parameters mentioned above could be recalibrated. Nonlinearity and

noise cannot be calibrated, but design of BMA180 was done in such a way, that those 2

parameters are minimized.

9.4.1 Offset re-calibration

The 0g-offset of the sensor is factory calibrated for all three axes. If a very high accuracy of the

0g-offset is important for the application, a recalibration after soldering is recommended.

The sensor provides 2 possibilities of recalibration, described in the following 2 subsections.