| The Microsoft Kinect has been a runaway holiday success; breathing another round of life into the gaming console market. The device has been found to have more heavy lifting than expected, in the form of a Marvell applications processor, in addition to the processor for motion recognition. As we can see from the front view, it looks as though there are three sensors to detect the gestures of the player – actually, we have an infrared emitter, infrared camera, and normal light camera. |
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| The PrimeSense part performs the necessary calculations to get a 3D image of the body in motion. Neither the web site, nor the reviews provide a particularly detailed/specific summary of how the system works, but a review of a PrimeSense Ltd. patent application (12/758,047) provides a nice picture (which we are using here) that is sufficient for this teardown. Essentially, the IR light source projects a pattern onto the player, which is detected by the IR camera, and variations in the pattern monitor the player’s movements. This is continously integrated with the 2D colour image from the other camera to give a 3D image of the player, which is then used to control the game being played.At right, we have also included the die markings and a metal 1 die photo.What we like about the technology is that it doesn’t load a CPU, and it is using USB PHY for on-board communications (something that we are seeing more and more of). |
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| Infrared image sensor Aptina is the winner for the Kinect, having gained a design win for both the IR and regular color sensors. The IR camera uses the MT9M001C12STM sensor. This sensor is based on technology that is quite old when compared to the latest sensors found in camera phones or DSLR cameras. The sensor itself is a 1.3 Mp sensor with a “huge” 5.2 µm pixel size, when compared to the latest 1.1 µm sensors. Because it is receiving IR, there are no color filters needed on the pixels. IR filtering is in the module, behind the lens. Given the die markings, we didn’t dig further to find any IR-specific design features. It seems that an off the shelf sensor was sufficient. The device has three levels of aluminum metallization with a 4T pixel architecture (the last image at right is the IR emitter). |
| The “secondary” color sensorFor comparative purposes, we thought it would be useful to show the sensor that is used for image capturing. This device is the MT9M112, with die markings K14M. It is also a 1.3 Mp sensor, though presumably the only benefit to matching the pixel count is so that the math is easier (or as part of product lifecycle management to allow full HD resolutions to be in future versions). The pixel size in this case is a smaller 2.8 µm. I think it is fair to say that these sensors deliver the performance required by the application without adding unnecessary costs. |
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Summary of Devices Catalogued
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| Stereo ADCTwo Wolfson Stereo ADCs with microphone preamps were found in the Microsoft Kinect. The datasheet describes this device as a low power stereo audio ADC, designed specifically for portable applications, such as minidisc and memory audio/voice recorders. |
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| Stereo USB audio interfaceA Texas Instruments USB streaming controller, with the package markings TAS1020B/TI logo 07W/A7SD, was also found. This device was designed specifically for applications requiring isochronous data streaming. |
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| Application processorAn Armada Series 800 MHz application processor by Marvell was also inside the Microsoft Kinect. Interestingly, this device is typically aimed at the e-reader market |
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| USB 2.0 controllerNEC D720114/023PG33/KOR |
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Analysis available on devices found in the Microsoft Kinect
Image Sensor Analysis on the Aptina MT9M001
High Resolution Die Photo and Metal 1 Die Photo on the PrimeSense PS1080 ASIC
