TrackPoints

You can get TrackPoints out of many types of laptop keyboard.

but the type I need,

is more hard-to-find.

Here's one part that works! IBM part number is 08K4959, the Fru number is 08K4988

I cannot find any more of these - I am looking!

and yet another type the strain gauge is separate, connecting into the keyboard circuitry

this last type would be very useful to me, if I can find some.

[edit] connecting them into a Micro Controller

TrackPoints use PS2 protocol

looking on the back there are ten pins

counting from the one nearest the edge we have

For the record,

2 (data),4(clk) are for connecting an additional PS2 mouse device to run in series

chop a PS2 plug off an old mouse or keyboard

figure out which wires are clock, data, +5v, 0v and connect them

to activate the device, we need to hold reset high for a little while, then pull it low

               2.2uF     Connect to Reset here     100K

(+5v) -----------||--------------*----------------/\/\/\--------------(0v)

This will do the trick nicely.

My old wiki details this process

Available here

Contains which commands to send / receive. Also PS2 protocol is described in here.

Circuit Diagrams are available on a child page of the above link: here!

Download - the main chip on the unit (the bigger one), made by Phillips

in this data sheet - a circuit diagram for a working TrackPoint module, and a brief description of how the chip functions

important pins ( start at dot, work counter clockwise )

2   data
5   reset
8   ground
22  +5v
24  clock