Additional bleeper?


Binky

Death's Steed
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(I think this has been mentioned before but not really discussed)

I propose that the pyra should have a piezo sounder in it somewhere.

It should be connected seperately from the main speakers, appear to software as a PC speaker / system bell, and have a solder jumper for people who want to be able to completely silence thier device.

Something like being able to produce a single square-wave tone in within a range of frequencies would be reasonable, although a single tone would do.

More than that would be lookshery (maybe you can do funny-shaped waves with Really Fast PWM?)

This could be useful for alerts which have to work regardless of volume wheel position, or for programs that are too simple or low-level to load fancy audio libs.

Since the things are flat, easy to drive and cheap, I can't really see any major downsides (although there may be some). 

piezo.jpg
 
sure. as long as i can have the choice to not have them. ill either be unable to hear them through my headphones which im using on pyra, or theyll be way out whack with anything else that makes a sound and will make my head ring with a single bell if it also goes through the headphone jack
 
Those are the same type of speakers used in game&watch style handhelds, and in musical birthday cards to this day.  Evidently it's possible to get a tune out of them, though not a very good sounding one.

I'm in two minds as to the suitability of these for the Pyra.  I'm not that convinced that it's much easier to interface with one of these than with a proper audio lib that's included in the OS, but I don't have any experience in that area (so far, I have always got away with system("aplay file.wav"); and the likes).  It also seems slightly wasteful to install a worse sounder when there are already two decent ones included, but I suspect it might be harder to wire a bypass around the volume wheel to get unfettered access to the speakers for alarms and suchlike.

Biggest argument against is the faff it might be installing it.  Where would you install it?  There may be space south of the battery provided the stylus doesn't get in the way, though how loud it would be when put on a solid table I don't know.  Other than that it would be possible to route it up to the lid and mount it behind the LCD or something, but ED's design already eliminates the wifi antenna going through the hinge as it slows down assembly.

When it comes down to it, this tends to sound like the ideal easy hack for novice hardware hackers, especially if one will fit in the base.
 
I like it better as an option for the user to install than to include it for every unit.
 
This can mostly just be simulated in software through the normal audio system.

The only problem is that you can't override the volume wheel in software, at least not if it's done like on the Pandora. I think a volume wheel override in software would be useful anyway, not just for bleeps, e.g. for setting wake-up alarms (with nice music, not just bleeps!) or receiving notifications etc at a pre-set absolute volume instead of according to the volume wheel. I don't know how hard that would be to implement though -- it would require hardware changes, and I don't want to lose the hardware volume wheel.
 
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I think it's nice to have and maybe this feature should be prepared, but it's absolutely unnecessary. It should be a hack option.

I don't have much experience with bleepers, but maybe you can already put one into your Pandora and drive it via GPIO.
 
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Wouldn't a bypass around the volume wheel casue trouble by adding complexity, and potentially interferance, to the audio circuits, and upset all those who are worried about buggy audio software making loud noises at the wrong times?

Normally they seem to be mounted in a slight recess in casing, with flying wires to a circuit board, but they aren't necessary. For example, my watch has  the sounding element glued to the inside back of the case, and has two tiny springs soldered onto the PCB. When you put the case together, the springs touch the two metal plates of the sounder and it all works.
 
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Wouldn't a bypass around the volume wheel casue trouble by adding complexity, and potentially interferance, to the audio circuits, and upset all those who are worried about buggy audio software making loud noises at the wrong times?
Maybe. I wouldn't know.

Buggy audio software is not acceptable anyway; having the option to "shut it down" by turning the volume wheel down is hardly a solution.

If there would be a volume wheel bypass, then I would make it so that it requires extra permissions (e.g. root) to enable the bypass.
 
Since the things are flat, easy to drive and cheap, I can't really see any major downsides (although there may be some).   
One obvious one: additional step in manufacturing that has to be done manually, therefore another failure mode + additional cost (human labor) for something thats not really necessary. 

I have never felt that the Pandora missed something like that so why have it on the Pyra?
 
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Buggy audio software is not acceptable anyway; having the option to "shut it down" by turning the volume wheel down is hardly a solution.
But: a solution! Bugs happen. And such a solution works. Always!
If there would be a volume wheel bypass, then I would make it so that it requires extra permissions (e.g. root) to enable the bypass.
Hm, I think it would be a better idea, if such a feature would be just very pandora specific. In that case bad ported applications would not notice this bypass, but a pandora alarm clock can e.g. set /proc/pandora/bypass_volume to 50 if needed and back to -1 if finished. ;) Furthermore I image an alarm clock, which wants permission to play a sound... when it should ring in the morning. :>
 
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