TrackPoint's drift cancellation

[jhonyl]

Hi,
I had a small discovery concerning the TrackPoint's drift: If you press one of the mouse button the recalibration doesn't occur, and hence non of the usual mouse drifts. I say non of the usual, because I read that the mouse drift cancellation algorithm is due to that Synaptics' TouchStyk (That's how they call the TrackPoint) is made of capacitors, and is sensitive to temperature changes. And so, I set the middle button to "none" (i.e. not scrolling or magnifying) and then kept it pressed while I gave the computer something to do, and raised the temperatures from 44C to 60C. When it got to 60C the mouse started to drift, but very gently, not like we know. Since I kept the middle button pressed the mouse kept drifting, and I could negate that drift with little effort with my finger. When I released the middle button, the mouse re-calibrated, and stopped drifting. Then I did the test in the opposite direction. I pressed the middle button, and kept the CPU free of chores. Again the drift started only after a major drop in the temperature has happened, and the CPU temp was 44C. But this time the drift was upwards, while before it was in a diagonal down to the lower left corner.

I now know why Synaptics do this, but I still think that they are overdoing it. After all it took a 14C change for some temperature related drift to happen. A 14C temperature change take quite some time to occur. Yet the drift cancellation algorithm happens so often, that many times it cancels my own movement in the process.

[jhonyl]

I pressed the middle button and put a bit of a tooth pick as a wedge to keep it pressed. The left and right buttons press didn't work well all the time, so I put the following lines into the AutoHotKey script to intercept the middle button signal, and it worked:


MButton::
sleep, 500
return

And now I am experiencing for the first time drift free mousing. It is nice when the mouse stay where I took my finger off of it, instead of taking a step backward right when I lift my finger in order to select something. It is also nice that it doesn't resist me on a long move from one side of the screen to the other. In case of a temperature related drift, I can always release the toothpick.

Kind of clumsy, and I loose the middle button, though I can get it back from an other key through AutoHotKey. I wish that someone could help me to find how to tweak it in software. There are a few documents on the Synaptics website.

PS. Mapping the right alt key to generate a middle button click:

RAlt::

Mouseclick, middle
return

Edit: I now use two business cards that I cut to size as a wedge to keep the middle button pressed. I discovered that the mouse starts to drift due to temperature change even at a smaller temperature change of the CPU. I guess there are other components that afect the trackPoint temperature more than the CPU. It still takes a few minutes untill a drift happens, and when it happens I pull out one of the business cards for a couple of seconds to cancel the drift.