Editing MX13 SpaceSaver Keyboard (section)

====IBM SpaceSaver II Keyboard====
[[Image:IBM-SpaceSaver-II.jpeg|thumb|right|300px|IBM Space Saver II keyboard.]]

The IBM SpaceSaver II (SSII) keyboard is a great source from which to harvest IBM TrackPoint components for use in custom keyboards and keyboard modifications.
The SSII uses a rubber-dome mechanism to implement its key switches and on that basis is not terribly interesting as an input device.
What makes the SSII stand out, however, is the inclusion of a TrackPoint IV with sufficient height to be usable on so-called "mechanical" keyboards.

The only other TrackPoint IV product known to have sufficient height is the [http://support.lenovo.com/en_US/product-and-parts/detail.page?&LegacyDocID=MIGR-4WKSWX IBM TrackPoint USB Space Saver Keyboard].
Other extant TrackPoint keyboards with sufficient height (e.g., the IBM Model M13, IBM TrackPoint II keyboard) are TrackPoint II devices, which lack the negative inertia feature of the TrackPoint III and the middle mouse button (used for scrolling) of the TrackPoint IV.
All other known TrackPoint implementations are for low-profile keyboards, such as those used on ThinkPad laptops.

It also helps that the TrackPoint stick on the SSII keyboard is black, which looks nice, and the button assembly does not take up a lot of space.
When selecting parts for the prototype build, other TrackPoint IV keyboards were surveyed (including those from ThinkPads), and the SSII button assembly had the smallest footprint as could be determined from pictures.

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[[Image:SSII-screws.jpeg|thumb|right|200px|SSII case screws hidden beneath middle mouse button.]]
When disassembling the SSII keyboard, it is necessary to carefully remove the middle mouse button to access and remove two screws, as seen in the picture on the right.
More information about the process is available [http://www.58bits.com/blog/2008/10/18/the-internet-is-amazing here].

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[[Image:SSII-TrackPoint.jpeg|thumb|right|200px|TrackPoint pointing stick and button assembly removed from an IBM SpaceSaver II keyboard. The pictured button assembly was cut from the SSII enclosure using a Dremel (i.e., it is not separable without damaging the keyboard).]]

The TrackPoint stick is easily removable from the SSII and can be adapted to staggered Cherry MX layouts with some modifications to the key switches.
The TrackPoint controller is implemented on the same circuit board as the SSII keyboard controller, however.
So it is harder, if even possible, to physically separate, though the two circuits are powered separately and can be run independently.
The approach taken on the MX13 therefore is to embed the entire SSII logic board, but only activate the TrackPoint portion.

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