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Today's Topics:

  1. Re: trying to track down a bug: Pd-extended 0.43-1 beta on
      Oneric 32 bit (Hans-Christoph Steiner)
  2. Re: [PD-announce] leer este            07 (laura plana)
  3. Re: (OT) safely connect piezo transducer to soundcard as
      microphone (Matteo Sisti Sette)
  4. Re: (OT) safely connect piezo transducer to soundcard as
      microphone (Matteo Sisti Sette)
  5. Re: HID double triggers (James Dunn)
  6. Re: (OT) safely connect piezo transducer to soundcard as
      microphone (Martin Peach)
  7. Re: (OT) safely connect piezo transducer to soundcard as
      microphone (Matteo Sisti Sette)
  8. Re: (OT) safely connect piezo transducer to soundcard as
      microphone (Martin Peach)


----------------------------------------------------------------------

Message: 1
Date: Sat, 21 Apr 2012 09:42:28 -0400
From: Hans-Christoph Steiner <hans@at.or.at>
Subject: Re: [PD] trying to track down a bug: Pd-extended 0.43-1 beta
    on    Oneric 32 bit
To: IOhannes m zmoelnig <zmoelnig@iem.at>
Cc: pd-list@iem.at
Message-ID: <65D79887-DF07-435A-85DB-EC0F96F9B59C@at.or.at>
Content-Type: text/plain; charset=us-ascii


On Apr 21, 2012, at 9:09 AM, IOhannes m zmoelnig wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 2012-04-16 20:44, John Harrison wrote:
>> Sorry for the delay on this. I downloaded today's binary build of
>> Pd-extended for Ubuntu 11.10 32 bit, then ran Pd-extended with -nrt in
>
> is it possible to build Gem (from the git "master" branch) yourself?
> what is the exact version it shows for Gem?

Gem in Pd-extended is the 0.93 branch, at commit 1458b4f8cfa12503bba94e2a8804f802f07efdaa

http://pure-data.svn.sourceforge.net/viewvc/pure-data/branches/pd-extended/0.43/externals/Gem/

.hc




----------------------------------------------------------------------------

                            kill your television





------------------------------

Message: 2
Date: Sat, 21 Apr 2012 14:47:54 +0000
From: laura plana <lauraplanagracia@hotmail.com>
Subject: Re: [PD] [PD-announce] leer este            07
To: pd-announce@iem.at
Message-ID: <BLU0-SMTP25695864525F1A8B623D9F5C9230@phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"

<b><span style="font-size: 25pt;">
<a  alt="cbrincoboraxdeslucirciquiribailesee"
id="bataholaatarquinarbromoacalabrotararchimandritauop3h"
href="iucogeduraadaponer.y56.info/eS/?msg=diezajase3fj&p=pd-announce@iem.at" >
pd-announce@iem.at clic aqu? pantalla de correo electr?nico</a></B><font color=#fffff4> 174zlbcaaveral
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------------------------------

Message: 3
Date: Sat, 21 Apr 2012 16:16:17 +0200
From: Matteo Sisti Sette <matteosistisette@gmail.com>
Subject: Re: [PD] (OT) safely connect piezo transducer to soundcard as
    microphone
To: Martin Peach <martin.peach@sympatico.ca>
Cc: PD-List <pd-list@iem.at>
Message-ID: <4F92C131.1030505@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 04/21/2012 12:38 AM, Martin Peach wrote:
> You could put a resistor in series to limit the current or a pair of
> diodes in parallel to clamp the voltage. Probably a pair of 1N4001s like
> this would work:
>
> IN---+------+-----OUT
> | |
> ^ v
> | |
> GND--+------+-----

Hi,

Thanks for the suggestion. If I understand correctly, here the
non-ideality of the diodes is what does the trick, and this would limit
the voltage to below the diode's drop, right? which is about 1V or so...

Now, thinking about it, wouldn't the following be even better? (this
hadn't come to my mind before)

  IN---+------+-----OUT
  |
  v
  |
  |
  ^
  |
  GND--+------+-----

with two ZENER diodes of appropriate reverse voltage? Facing each other?

So within the "allowed" voltage range there would be no (or much less)
distortion?

Maybe I'm being too naive here?



------------------------------

Message: 4
Date: Sat, 21 Apr 2012 16:24:52 +0200
From: Matteo Sisti Sette <matteosistisette@gmail.com>
Subject: Re: [PD] (OT) safely connect piezo transducer to soundcard as
    microphone
To: pd-list@iem.at, richduckworth@yahoo.com
Message-ID: <4F92C334.9090103@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 04/21/2012 02:14 AM, richard duckworth wrote:
> Piezo mics should go through a very high impedance buffer stage.
> ......

Thank you very much, that was illuminating.

However for now I'm was looking for a simplistic solution without the
slightest care for sound quality, as I'm just using the signal to take
its envelope in order to detect knocks and the like.

But now I know why it sounds the way it sounds and that with an
appropriate high impedance buffer stage it can sound way better, the day
I'll need it :D





------------------------------

Message: 5
Date: Sat, 21 Apr 2012 15:22:22 +0100
From: James Dunn <james@4thharmonic.com>
Subject: Re: [PD] HID double triggers
To: IOhannes m zmoelnig <zmoelnig@iem.at>
Cc: pd-list@iem.at
Message-ID: <4F92C29E.5000703@4thharmonic.com>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

Quoth IOhannes m zmoelnig, on 21/04/2012 14:23:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 2012-04-18 20:27, Andrew Faraday wrote:
>> I've had this problem before with [hid], apparently it's a hardware
>> issue called 'debouncing', which is often ignored because it is often
>> irrelevant (pushed is pushed, for game controllers, rather than a
>> button-on/button-off signal used for most music systems).
>>
>> You can deal with the problem in pure data by using a trigger, float and
>> delay of one millisecond. See the attached patch, click the message
>> boxes and watch your terminal for the result.
> [change] seems to be the more appropriate solution here...
>
> fgmasdr
> IOhannes

Thanks for the suggestion. The problem I have with these two solutions
is that they only work when the double triggers are in sequence.
Sometime they arrive like this:

[hid] 0.7, written by Hans-Christoph Steiner <hans@eds.org>
<mailto:hans@eds.org>
    compiled on Apr 15 2012 at 08:12:47
[hid] opened device 4 (/dev/input/event4): AT Translated Set 2 keyboard
print: key key_j 1
print: key key_l 1
print: key key_j 1
print: key key_l 1
print: key key_j 0
print: key key_j 0
print: key key_l 0
print: key key_l 0

So I would need to store the value of each key individually and check
each one with [change].
Instead of this long-winded method, I've downloaded [linuxevent] which
is working nicely so I think I'll stick with this even though it may be
deprecated?

Surely this is a bug with [hid] though?

James
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------------------------------

Message: 6
Date: Sat, 21 Apr 2012 11:03:25 -0400
From: Martin Peach <martin.peach@sympatico.ca>
Subject: Re: [PD] (OT) safely connect piezo transducer to soundcard as
    microphone
To: Matteo Sisti Sette <matteosistisette@gmail.com>
Cc: PD-List <pd-list@iem.at>
Message-ID: <BLU0-SMTP534D94809FC233CDA94E87ED230@phx.gbl>
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed

On 2012-04-21 10:16, Matteo Sisti Sette wrote:
> On 04/21/2012 12:38 AM, Martin Peach wrote:
>> You could put a resistor in series to limit the current or a pair of
>> diodes in parallel to clamp the voltage. Probably a pair of 1N4001s like
>> this would work:
>>
>> IN---+------+-----OUT
>> | |
>> ^ v
>> | |
>> GND--+------+-----
>
> Hi,
>
> Thanks for the suggestion. If I understand correctly, here the
> non-ideality of the diodes is what does the trick, and this would limit
> the voltage to below the diode's drop, right? which is about 1V or so...
>
> Now, thinking about it, wouldn't the following be even better? (this
> hadn't come to my mind before)
>
> IN---+------+-----OUT
> |
> v
> |
> |
> ^
> |
> GND--+------+-----
>
> with two ZENER diodes of appropriate reverse voltage? Facing each other?
>
> So within the "allowed" voltage range there would be no (or much less)
> distortion?
>
> Maybe I'm being too naive here?
>

Yes that's the next step, if you want a larger voltage range. Or use
strings of ordinary diodes to add about .6V per diode. I think if you
only want to detect hits it doesn't matter too much. Ideally, you would
know the voltage range of your audio input and set the levels to fit that.

Martin



------------------------------

Message: 7
Date: Sat, 21 Apr 2012 17:07:12 +0200
From: Matteo Sisti Sette <matteosistisette@gmail.com>
Subject: Re: [PD] (OT) safely connect piezo transducer to soundcard as
    microphone
To: Martin Peach <martin.peach@sympatico.ca>
Cc: PD-List <pd-list@iem.at>
Message-ID: <4F92CD20.7050907@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

By the way, thinking about it again, I think the sound card applies a DC
voltage to its input (about 3V) (in order to polarize an electret
microphone), so I'm afraid the parallel diodes can't work because the
one pointing downwards would always be "on".........

On 04/21/2012 05:03 PM, Martin Peach wrote:
> On 2012-04-21 10:16, Matteo Sisti Sette wrote:
>> On 04/21/2012 12:38 AM, Martin Peach wrote:
>>> You could put a resistor in series to limit the current or a pair of
>>> diodes in parallel to clamp the voltage. Probably a pair of 1N4001s like
>>> this would work:
>>>
>>> IN---+------+-----OUT
>>> | |
>>> ^ v
>>> | |
>>> GND--+------+-----
>>
>> Hi,
>>
>> Thanks for the suggestion. If I understand correctly, here the
>> non-ideality of the diodes is what does the trick, and this would limit
>> the voltage to below the diode's drop, right? which is about 1V or so...
>>
>> Now, thinking about it, wouldn't the following be even better? (this
>> hadn't come to my mind before)
>>
>> IN---+------+-----OUT
>> |
>> v
>> |
>> |
>> ^
>> |
>> GND--+------+-----
>>
>> with two ZENER diodes of appropriate reverse voltage? Facing each other?
>>
>> So within the "allowed" voltage range there would be no (or much less)
>> distortion?
>>
>> Maybe I'm being too naive here?
>>
>
> Yes that's the next step, if you want a larger voltage range. Or use
> strings of ordinary diodes to add about .6V per diode. I think if you
> only want to detect hits it doesn't matter too much. Ideally, you would
> know the voltage range of your audio input and set the levels to fit that.
>
> Martin
>




------------------------------

Message: 8
Date: Sat, 21 Apr 2012 11:31:28 -0400
From: Martin Peach <martin.peach@sympatico.ca>
Subject: Re: [PD] (OT) safely connect piezo transducer to soundcard as
    microphone
To: Matteo Sisti Sette <matteosistisette@gmail.com>
Cc: PD-List <pd-list@iem.at>
Message-ID: <BLU0-SMTP92CD4B67CD820FF6D452E2ED230@phx.gbl>
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed

On 2012-04-21 11:07, Matteo Sisti Sette wrote:
> By the way, thinking about it again, I think the sound card applies a DC
> voltage to its input (about 3V) (in order to polarize an electret
> microphone), so I'm afraid the parallel diodes can't work because the
> one pointing downwards would always be "on".........


That sounds unlikely. If it had 3V on the input you would always get a
high value with nothing connected. Anyway, it's better to use a line
input with piezos because their output is in volts, not millivolts.

If it really has 3V on it, putting a 10k resistor in series with the
input will protect it and still pass the piezo signal, which is very
high impedance, so won't be diminished much:

IN----+----+----/\/\/----OUT
      |    |
      ^    V
      |    |
GND---+----+-------------

Martin


>
> On 04/21/2012 05:03 PM, Martin Peach wrote:
>> On 2012-04-21 10:16, Matteo Sisti Sette wrote:
>>> On 04/21/2012 12:38 AM, Martin Peach wrote:
>>>> You could put a resistor in series to limit the current or a pair of
>>>> diodes in parallel to clamp the voltage. Probably a pair of 1N4001s
>>>> like
>>>> this would work:
>>>>
>>>> IN---+------+-----OUT
>>>> | |
>>>> ^ v
>>>> | |
>>>> GND--+------+-----
>>>
>>> Hi,
>>>
>>> Thanks for the suggestion. If I understand correctly, here the
>>> non-ideality of the diodes is what does the trick, and this would limit
>>> the voltage to below the diode's drop, right? which is about 1V or so...
>>>
>>> Now, thinking about it, wouldn't the following be even better? (this
>>> hadn't come to my mind before)
>>>
>>> IN---+------+-----OUT
>>> |
>>> v
>>> |
>>> |
>>> ^
>>> |
>>> GND--+------+-----
>>>
>>> with two ZENER diodes of appropriate reverse voltage? Facing each other?
>>>
>>> So within the "allowed" voltage range there would be no (or much less)
>>> distortion?
>>>
>>> Maybe I'm being too naive here?
>>>
>>
>> Yes that's the next step, if you want a larger voltage range. Or use
>> strings of ordinary diodes to add about .6V per diode. I think if you
>> only want to detect hits it doesn't matter too much. Ideally, you would
>> know the voltage range of your audio input and set the levels to fit
>> that.
>>
>> Martin
>>
>
>
>




------------------------------

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