Sudden Motion Sensor

With Sudden Motion Sensor (SMS, German " Sudden Motion Sensor " ) is a patented system of the U.S. computer manufacturer Apple called that, in case of sudden movements of equipment containing a hard drive that instantly parks the write and read heads so they do not damage the storage medium when dropped ( head crash ). The procedure in this way reduces the risk of data loss. If the unit is brought back to a normal position, the reading heads are released. The system is similar to the Active Protection System, which is available in ThinkPads since about 2003.

With an acceleration sensor is attempted based on the change of the axis of the apparatus and analysis of acceleration forces to detect a possible fall.

The technique was first used in the presented on 31 January 2005 refreshed PowerBook G4 processor used. The Sudden Motion Sensor is not part of the disk, but integrated into the motherboard, so that this protection mechanism is available, even after a hard disk replacement.

In July 2005, the technology was also introduced in the iBook. The 2006 featured product lines MacBook and MacBook Pro are equipped with the Sudden Motion technology.

From Java you can access the data of the SMS example with the open source software Jilt.

Therefore, there are now many programs that use the Sudden Motion Sensor to realize, for example, an alarm system ( iAlertU ) or to change the desktop when the user of the notebook a slight lateral blow to ( SMacBook ).

Another application is the free program SeisMac, which can turn your Apple laptop into a seismograph, similar use, see the sensors in a QCN BOINC -based project for tracking and reporting of earthquakes.

Meanwhile, other laptops, such as HP, Acer or Lenovo are equipped with the sensor and are partially supported by above-mentioned programs.

• Sensor
• Hardware