[Kinect Teardown (5)] 3 Circuit Boards Examined
Continued from [Kinect Teardown (4)] Mysterious Yellow Stickers
Finally, we started to break down the three-layer module of the Kinect. First, we removed the large circuit board on the third layer, which was connected to the small and middle-size circuit boards on the middle layer by screws and connectors.
There were cylindrical spacers between the large and middle-size circuit boards and between the large and small circuit boards. The spacers not only made space between the circuit boards but also served as screw holes. The screw holes corresponded to the holes made on the circuit boards, and they were used to join the middle-size and small circuit boards to the large circuit board.
In addition to the screws, the three circuit boards were connected by two connectors (one connected the large and middle-size circuit boards while the other connected the large and small circuit boards).
Large circuit board
We examined the large circuit board first. In the center of the front side, which was facing the back of the Kinect, there was a chip that seemed to be Renesas Electronics Corp's "μPD720114" USB 2.0 hub controller chip, which was printed with "D720114." On the left part of the front side, there were two "WM8737" A-D converters (printed with "WM8737G"), which were developed by Wolfson Microelectronics plc and supports stereo audio. The WM8737 can also be used as a preamplifier.
When looked from the side, the radiation fin located on the right part of the large circuit board's front side seemed to be attached to a large chip. Only part of the radiation fin, which had a T-shaped cross section, was in contact with the large chip.
We tried to remove the radiation fin but found it difficult. If we had removed it by sheer force, it might have been broken. So, we decided to detach the fin later.
Small circuit board
Then, we took out the middle-size and small circuit boards on the middle layer. On one side of the small circuit board (the side facing the large circuit board), there was Texas Instruments Inc's "TAS1020B" USB 1.1 controller chip, which is for audio processing, as well as Kionix Inc's "KXSD9" three-axis acceleration sensor.
The main body of the Kinect moves up and down depending on the location of the user, etc. It seemed that the tilt of the main body was detected by the acceleration sensor and the data collected by using the sensor was used to determine the location and motion of the user.
Middle-size circuit board
The middle-size circuit board was mounted with PrimeSense Ltd's "PS1080" SoC (system-on-chip), which was printed with "PS1080-A2" and measured 5 x 5mm. Microsoft Corp announced in its news release that it employed PrimeSense's technologies for the Kinect, and it turned out to be true.
The PS1080 calculates depth information for each frame from the data collected by an infrared camera. And it transmits the data collected by a visible light camera and a microphone and the depth information to a host device via the USB 2.0 interface.
Then, we moved on to examine the first layer, which were mounted with an infrared laser, a camera for infrared light and a camera capable of detecting visible light.