geekhack
geekhack Community => Keyboards => Topic started by: HaaTa on Sat, 13 March 2010, 07:18:31
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Been reading through the xkb documentation as of late and found an interesting description on keyboard bells:
Bell features extension
It can seems that this part has not relation to keyboard.
Moreover, for users of computers where keyboard, display and "speaker" are independent devices such combination can looks very strange. But since in some hardware bell is placed in keyboard and produce key_click sound at every key press so X's design consider that bell control is keyboard mode duty.
I should note that bell control presents in old (core protocol) keyboard module. With special requests to X-server application can change key_click parameters (tone, duration and loudness) and produce this sound when it needs.
The XKB module offers advanced bell features and allows not only cause click sound but play music fragment. Of course to provide such "music accompaniment" is too complex task for keyboard module. First aff all it needs some 'sound database' and the second it has to support many different hardware (sound cards).
Therefore XKB design assumes that there must exists special application ("juke-box") for sound play. And the XKB simply generates special event (instead og click sound) that can be delivered to any application as all other events. Juke-box has to say to X-server at start that it acceps some kind of events (in this case xkb bell-events).
Of course, if such music box presents its ability is not limited with bell sound with different tone/duration play. It would can play many music fragments from own database.
Therefore XKB bell events contains not sound parameters but simply some "sound name" (or "bell name"). And music box has to have some table where each bell name is bound to concrete music fragment.
So application working with XKB can request not simple bell but any sound specifying its name. Note that XKB doesn't perform any check of such sound names but simply retranslate them to juke-box.
Of course XKB not only retranslates "sound requests" from applications to juke-box but can request sound for own needs (when it changes own state).
Taken from http://pascal.tsu.ru/en/xkb/internals.html (http://pascal.tsu.ru/en/xkb/internals.html)
Anyone have any suggestions? Perhaps Topre "thocking" to mask out Alps "clacking"?
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Not surprised, it was very common for terminals back in the day to click or beep when you pressed keys to let you know that they had been registered. Given X11's terminal roots, it makes sense that they'd implement that functionality.
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The DEC equipment is the only one I remember that played the ^G bell throught the keyboard's beeper. Normally the LK201 keyboard made a short beep-tick for every keypress. That kb was so mushy bad it was required to have the beep ticks for feedback.
I X11 on my mac, and ^G's from xterm or whatever play a system sound.
I got some cherry POS keyboards with beepers in them. They normally beep when you get a good magstrip or barcode read. But you can configure them to tick the beeper for each keypress too.
When I was a teenager they still had some ancient 3270 terminals in the court clerk's office. They had a SOLENOID in the terminal that fired on each keypress. Maybe you can hang a FET off the parallel port to fire a solenoid. That would be über kuhl.
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They had a SOLENOID in the terminal that fired on each keypress. Maybe you can hang a FET off the parallel port to fire a solenoid. That would be über kuhl.
While you're at it, how about an optical transmitter, such as they use in MIDI, to signal an optical receiver that triggers the solenoid that controls an audio oscillator which triggers the clapper on your desk lamp?
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Hah. The Clapper. Someone thought it would be funny to get me one as a gift. I usually operated it by banging the shift key or something on my mitsumi kb.
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I have no idea why IBM bothered including a solenoid on those things, the beam spring is more than enough to let you know that you've pressed a key! Perhaps it was to do with making the user aware of potential electronic failures with the keyboard.
The LK-201 I've used (with a VT-320) didn't beep. Perhaps it needed to be set up in a particular way? But either way, the keyboard on that thing is a nightmare.
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I remember on one of my old computers, I could change a setting in bios set-up to make the computer beep with every key stroke.
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From my understanding so far, it would be possible to generate different sounds based upon the state of the keyboard. So things like a piano aren't out of the range of possibility (Though there are far better implementation of such a device...).