On its developer blog on Tuesday, Microsoft talked about how Windows 8 will use sensors to optimize the user experience. As the OS will be used on tablets and notebooks as well as desktop PCs, Microsoft found it important to include an automatic adaptive brightness that uses ambient light sensors. This feature aims to strike a balance between reading comfort, battery life and legibility when outdoors.
An accelerometer will talk to the OS to automatically put the screen in a landscape or portrait orientation, which is again applicable mainly to tablets. The company also ensured it would have built-in support for developers in its software so they can easily integrate sensors into their app builds.
Support is included for accelerometers, magnetometers, and gyro sensors after much experimenting with these sensors on their own or in combinations of two. This was needed in order to ensure fluid, noise-free movement recognition. Microsoft calls this "sensor fusion," and said it has created a sort of nine-axis sensor system.
Some of the inputs need to the combined for apps such as 3D games, compass apps, augmented reality apps or enhanced navigation apps. These inputs may include a compass that compensates for tilt that a user may not be aware of, or the incline of the hardware.
Microsoft then made specifications for hardware makers using its Windows certification guidelines to ensure conformity. Tests are included with the Windows Certification kit to allow hardware makers to test their gear.
A driver was made by Microsoft that would work with all Windows-compatible sensor packages that connect over USB or lower-power busses like I2C.
To save power during the process, the company tried to retain as much of the processing of sensor data is done in the hardware, saving the CPU from computing it. Filtering mechanisms were also said to have been developed to ensure no more data than is needed for the current task is sent to the CPU.
The Samsung Windows 8 Developer Preview tablet given away at the build conference last year included the nine-axis sensor fusion system. The system can be bought from ST Microelectronics. It connects over USB and works with the HID sensor class driver in Windows 8.