[Kinect Teardown (1)] Breaking Down Kinect's Stand
Nikkei Electronics Teardown Squad started to tear down the "Kinect for Xbox360," a motion controller for Microsoft Corp's "Xbox 360" game console, with help from Japanese engineers.
Before breaking down the controller, we would like to review its features.
The Kinect, which was launched Nov 4, 2010, in the US, enables to play TV games with motions and voices. And players do not have to hold a device in hand. For example, in a racing game, the car on the screen can be controlled by moving the hands as if turning a steering wheel and tilting the body.
The controller can be used not only for playing games but for handling video and music contents. For example, when the user says, "Xbox, Play," the console starts playing a paused content.
Such operations were realized by combining a range image sensor called "3D depth sensor," an RGB camera (visible light sensor) and an "array microphone," which consists of four microphones. With those sensors, the Kinect detects the movements of, for example, human joints to determine the user's motions.
The core technology of the Kinect is its range image sensor, which was developed based on the reference design of PrimeSense Ltd's sensor technology. With this technology, a far-red light is emitted, and its reflection is detected by a CMOS sensor. Then, the distance to an object is determined through arithmetic processing conducted by a dedicated SoC (system-on-chip).
Microsoft has not disclosed the details of the Kinect's range image sensor such as its specifications. So, we estimated them based on the reference design of PrimeSense, etc.
The range image sensor seemingly shines a well-known laser light pattern in the angle of coverage and detects the distance to and the structure of an object based on the geometric distortion of the pattern. In the reference design "1.08" of PrimeSense, the resolutions in the planer direction (x-axis and y-axis) and the depth direction (z-axis) are 3mm and 1cm, respectively, when the distance to an object is 2m. The delay time is 40ms on average.
Well, that's enough for the review. We set out to tear down the stand of the Kinect. When we turned over the controller, there was a sticker indicating that it is equipped with a class 1 laser. It proves that the Kinect uses a laser device for the infrared radiation source.
After removing a non-slip strip and screws from the stand to take out one side of the chassis, we found a metal plate. On the plate, there were several screws and parts that looked like clamps.
"Too many screws," said an engineer who looked at the plate.
Then, we removed the screws from the metal plate and detached the plate to look inside the stand. There was a tilt motor that moves the sensor unit up and down as well as gears used for increasing the torque.
We tried to remove the stand to tear down the main body, which is equipped with various sensors. However, it turned out to be not an easy task to remove the stand. It seemed that the stand can be easily detached after disassembling the main body. So, we decided to tear down the main body first.