I think this pressure sensitive input is great.
I had no idea the passive digitizer in these devices could detect anything more than boolean values.

Obviously the n800 is no Wacom tablet but it would be sweet to be able to adjust how much the pressure applied changes the line's width. Like there could be a menu option where the user can adjust the pen tool's maximum and minimum widths as modified by the stylus pressure. Also maybe alpha transparency of the drawn line could be modified by pressure as well.

Any floating point conversion has to be downstream of the actual packet decoding. There must be a certain fixed number of bits allocated to raw pressure data, which is where the answer to Karel's question resides.

it would be also great if it could detect alternate touches, ie. with the stylus's back (to erase, for instance)

to calculate the actual brush size from the pressure, i use this:
first, pressure is "clamped" between 0.1 and 0.35 (getting a value >0.35 requires too much and immediate force)
then it's just:
ceil(brush_size*pressure_value/0.35)
so, the brush size you select from the menu is the maximum brush size you will get if you apply a pressure of 0.35 and up. (also, ceil rounds the number up)

so, pressure sensitivity actually "increases" with the increased brush sizes. getting alpha channel might not work but I could also try to differentiate the color tone so it still makes sense with narrow brushes.

There are possibilities here. I'm not dreaming that an app like ArtRage could run on the N800, but maybe someone will use the pressure sensitivity as the basis of a more artsy drawing app (no offense meant towards Maemopad+, obviously ).

yeah, if somebody got the lcd specsheet or examined the touchscreen driver we could get some info on that. i doubt asking nokia for specs would work.

Unfortunately I can confirm, I have a similar reduction in the screen's sensitivity. In my case this is on the right edge, along the vertical scrollbar and getting a bit wider at the bottom. I first noticed it when the delete button on the virtual keyboard was not responding as well as the others. The MaemoPad+ test (courtesy of ColonelMustard ) shows it nicely. I think my problem is not very serious though, with just a bit more pressure it works fine. Interestingly drawing a line across the ominous area works fine, it is the stylus tapping that's affected.

Did some maemopad+ tapping myself. Quite a clear pattern. Not such a big problem, except for the extreme right edge... you really have to use force to get the scrollbars moving.

had mine only a few days but I have not noticed this issue yet.

One thing I noticed about the screen is that the right edge gets much warmer than the rest of the screen. It also looks kind of yellowish when the screen should be all white during booting

Anyone else see this?

Does recalibration of the screen help? Or is it just simply hardware failing?

Rich

As far as I know the touchscreen calibration aligns the pressure sensitive matrix to the visual screen matrix, as the two are not necessarily overlaping.