[chuck-users] odd hid issue (touchpad)

Hans Aberg haberg at math.su.se
Sat Jul 18 15:15:41 EDT 2009

On 18 Jul 2009, at 20:26, Kassen wrote:

> In recent years the quality of high performance mice has gone up  
> quite a bit, probably originally inspired by games like Quake. It  
> was chiefly mouse signals that I was refering to.
> I haven't checked that out.
> It can become relevant when using a mouse as a general purpose  
> sensor, for example to  scan a turntable platter's rotation. In that  
> case more resolution and a higher poll rate will lead to a more  
> expressive instrument.

That is an interesting use. If one does not have a turntable to  
scratch, I checked one can use the top of a matte CD or DVD - I only  
tried without print, and the underside (that carries the data) didn't  
work. So that might serve as an interface to scratch some audio-file

There are laser turntables, but they are pretty expensive, and I don't  
know if they can be scratched:

>>> Sadly (I feel) the quality of keyboards hasn't made the same  
>>> progression and keyboard ghosting is now typically worse then it  
>>> was on keyboards from the 80's.
>> On the Mac side, this was a problem in the 1990s - they would wear  
>> out after awhile - but not lately.
> Sorry, but I haven't yet seen a keyboard that I liked as much as the  
> old IBM Model M's. This is -of course- largely a matter of personal  
> taste and application.

These are called "extended keyboards", or full size, at least on the  
Mac side
I have an old Mac one, where the function keys are without gaps and no  
space the other keys. This was very good for the diatonic key map, as  
it becomes enlarged. But I found it difficult to do ornaments on it:  
the keys are a bit too chevy. It is A1048 here:
I have for couple of months used the A1242 - it is much better on  
ornaments, but not as good as a musical instrument. The rather short  
action takes some time to get used to.

The large one might still be good for playing bass.

> Windows is notorious for letting users install drivers on their own.
> I have to say that I don't see any harm in that. We can't expect a  
> OS maker to know ahead of time what sort of exotic devices and cards  
> we'd like to add to our computer. I do agree that standard devices  
> are a big leap up, with most things I can throw out the manual and  
> discs and simply plug it in, expecting it to work. Good thing too as  
> I don't like manuals and discs that much. If your mouse or webcam  
> needs a manual it could probably do with a severe redesign, I feel.

There was a adding cards to the computer also on the Mac, but they are  
mostly gone now, because the CPU/GPU are so powerful, it is not needed.

> also, the Mac short keyboards have a special "function" key, that  
> lets one to supply some of the keys of an extended keyboard, plus  
> some for special Mac use. The function key was not reported at all,  
> and pressing it did not report the extended keyboard key values. So  
> it has some USB function not covered by the HID standard, it seems.
> Yes, I think those are a exception. I have a "fn" key on this  
> laptop's keyboard as well, it deals with things like screen  
> brightness, sleep/suspend, locking and so on. The strange thing is  
> that ChucK doesn't register it as a HID key. We might initially  
> suspect that it would talk to the hardware directly for things like  
> screen brightness but the OS (Linux in this case) is clearly aware  
> of it as it -for example- shows a little meter to indicate the  
> change in brightness. Maybe it's the actual function (brightness,  
> locking, etc) that is linked to a "keypress" and the OS might be  
> unaware of there not being a single dedicated key for those.  
> Especially with the way some laptops deal with NumLock that approach  
> might lead to greater compatibility, I'm not sure, but that could  
> still be according to the standard.

This is what the driver would do. A pure HID device might not need a  
special driver, as the OS might supply a generic one.

One reason to avoid custom supplied drivers is that they do low level  
things that may cause the computer to crash. On Macs, that is called  
"kernel panic". Basically, it means that the kernel running the  
processes gets some code that it cannot handle. Often, there is a  
driver for a piece of hardware involved. The hardware, the OS and the  
computer, though, are fine.


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