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Revision as of 06:19, 24 March 2010 by flaviofabricioferreira (Talk | contribs)

Archived:How to get accelerometer data of N900 using Qt

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Introduction

In this post, I will demonstrate how to develop a Qt Application that will to get the information of accelerometer sensor at N900 device.

An accelerometer is a device that measures proper acceleration, the acceleration experienced relative to freefall.Single- and multi-axis models are available to detect magnitude and direction of the acceleration as a vector quantity, and can be used to sense orientation, vibration and shock. Micromachined accelerometers are increasingly present in portable electronic devices like mobile phones and video game controllers, to detect the orientation of the device or provide for game input.

Accelerometer Data at N900

The accelerometer data is sysfs file information.Sysfs is a virtual file system provided by Linux 2.6. Sysfs exports information about devices and drivers from the kernel device model to userspace, and is also used for configuration.

The three coordinates of accelerometer sensor is in a text file provided on one line and separated by white space. This file is at path below:

/sys/class/i2c-adapter/i2c-3/3-001d/coord

The values are in mG (milli G). 1000 = 1 G. The g-force experienced by an object is its acceleration relative to free-fall like described above.

At N900 device , the values are connected to the position showed below.

PostN900Accelerometer.png

The Code

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