Electronic – What are the holes on an optical flow sensor IC

The 74HC244 is the typical device for connecting to/disconnecting from a bus. It's an octal tri-state buffer (or rather a dual quad buffer). You'll need the tri-state feature to disconnect completely from the bus. The gates would set the bus high or low, but that wouldn't allow another device on it.

But since you're talking about a data bus you probably want a bidirectional buffer. Then you can use the 74HC245.

You have a DIR pin to control the direction and a /OE which can make the buffer tri-state.

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JustJeff mentions the 74HC374 octal tri-state D flip-flop. (Note: I'll talk about the 74HC574, which is functionally the same, but has a more logical pinout.) The 74HC574 is indeed an interesting part, and a classic since the SN74xx series. While the 74HC245 will give you a tri-state buffer, the 74HC574 has a memory function too, in the form of an octal D flip-flop. Great to make registers, and through the tri-state connection to the bus you can route your data flow easily.
There's a drawback to this, however. The register's output is only available to the bus, so all communication would have to pass there, so that the bus will become a bottle-neck. Therefore I think it's better to replace the 74HC374 by a 74HC273 octal D flip-flop followed by a separate 74HC244 tri-state buffer for the connection to the bus. That way the register's output is also available internally when some other signal occupies the bus. (I don't know if there's a function compatible part with the more logical pinout. You may also use a 74HC574 with /OE hardwired to ground.)

Kinect from Microsoft is a motion, gesture and sound sensing system that uses a proprietary stereoscopic webcam and microphone to sense physical position, movement and voice commands from the user. While it was originally developed for the XBox 360 gaming console system, it is now a popular and supported peripheral for Windows PCs as well.

Kinect has a Windows SDK, that permits high-level code to accept gesture and movement input. Quoting from the Kinech API page:

Kinect for Windows gives computers eyes, ears, and the capacity to use them. With Kinect for Windows, thousands of businesses and developers are creating applications that put people first—allowing their customers to interact naturally with computers by simply gesturing and speaking.

For people familiar with Windows / .net software development, the Kinect SDK is known to be very easy to use. A Kinect device will be required for Kinect development, a generic webcam isn't good enough.