Subject: MAX Digest - 21 Apr 1999 to 22 Apr 1999 (#1999-123)
Date: Fri, 23 Apr 1999 00:00:02 -0400
From: Automatic digest processor 
Reply-To: MAX - Interactive Music/Multimedia Standard Environments
     
To: Recipients of MAX digests 

There are 14 messages totalling 574 lines in this issue.

Topics of the day:

  1. the BBQ object (of desire) (3)
  2. Force Sensitive Resistors?
  3. Force Sensing Resistors
  4. cliqs & klocs goweway! (2)
  5. Force Sensitive Resistors (2)
  6. FSR
  7. MAX Digest - 20 Apr 1999 to 21 Apr 1999 (#1999-122) (2)
  8. sensor question, cont.
  9. Digital click removal

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

Date:    Thu, 22 Apr 1999 00:45:13 -0400
From:    Nicholas Longo <71477.2332@COMPUSERVE.COM>
Subject: Re: the BBQ object (of desire)

<<>From:    Peter Nyboer 

<<>Peter "Is BBQ off-topic?" Nyboer

<<(with apologies to our wonderful vegetarian and vegan colleagues), etc.

Actually, if you're in Berkeley (correct spelling) and hanging around at
1750 Arch St. you don't have to take the bus to Oakland for breakfast.
You're within walking distance of the world famous "Gourment Ghetto".
Every other doorway along a mile long stretch of Shattuck Ave. is an
eating establishment, including side streets.  The best (veggie) breakfast
is Smokey Joe's Cafe, just south of Cedar and Shattuck.

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

Date:    Thu, 22 Apr 1999 01:52:30 -0500
From:    rb 
Subject: Force Sensitive Resistors?

> Date:    Wed, 21 Apr 1999 02:23:30 -0400
> From:    jmw/cmu 
> Subject: Force Sensitive Resistors?
>
> I'm looking for a source of FSR & linear potentiometers ( ribbon
> controllers).
> I did a search but only found some large industrial mnaufacturers.
> Any help would be appreciated.
>
> jmw

try searching on interlink

(InterLink Electronics)

they make fsr, plus they sent me a couple of samples

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

Date:    Thu, 22 Apr 1999 02:37:06 -0400
From:    Ken Gregory 
Subject: Force Sensing Resistors

>I'm looking for a source of FSR & linear potentiometers ( ribbon
>controllers).
>I did a search but only found some large industrial mnaufacturers.
>Any help would be appreciated.
>
>jmw

http://www.jameco.com/cfm/viewdesc.cfm?part_num=150551
      "flex" sensor

http://www.imagesco.com
     A source for Bend(a type of FSR) Sensors:

http://www.ace.co.uk/simltd/fsrhome.htm
   A source for FSR (force sensing resistors)

Interlink Electronics
ph. 800-340-1331 toll free in North America
ph. 805-484-8855 for quotes
fax 805-484-8989 product support
   A source for FSR (force sensing resistors) These people have a website,
but it crashes my Mac when I visit. The wsite only details the products
they use FSRs to make. They have an evaluation kit which is a good deal
with lots of FSRs to try out plus notes and suggested circuits.

http://www.infusionsystems.com/
  Infusion make most of their sensors with FSRs

>If you would do some craftwork (?) put some pieces of the antistatic foamed
>plastic, which is used to transport Integrated Circuits between 2
>electrodes. If you press onto the 2 electrodes, the resitance of the
>antstatic-plastics goes down. Its not a 0,05% solution, but it works fine
>(and cheap)

This method is detailed in Radio Shacks 'Engineers Mini-Notebook Sensor
Projects' by Forest M.Mimms III. catalog number 62-5026

Hope this helps.

Cheers,
ken

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

Date:    Thu, 22 Apr 1999 08:16:34 +0200
From:    "Dr. Karlheinz Essl" 
Subject: Re: cliqs & klocs goweway!

Roland Cahen & Ruth Sefton-Green  wrote:

> What kind of solution can you find to get rid of digital cliks ?
> Is there an existing anticlick MSP object ?
> One which would detect a steeper amplitude slope variation in a short
delay
> preferably in a quiet moment ?

I am successfully avoiding clicks by using a public domain VST plugin
called "limiter" from the mda series. A link could be found it on
Steinberg's website

        http://www.steinberg.com

As you might probably know, VST plugins can be used in MSP patches by using
the VST~ object.

Hope that helps,

   Dr. Karlheinz Essl - Composer
   Vienna / Austria
   Studio for Advanced Music & Media Technology
   http://www.essl.at/

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

Date:    Thu, 22 Apr 1999 10:30:19 +0100
From:    Trond Lossius 
Subject: Re: cliqs & klocs goweway!

Roland wrote:

> What kind of solution can you find to get rid of digital cliks ?
> Is there an existing anticlick MSP object ?
> One which would detect a steeper amplitude slope variation in a short
delay
> preferably in a quiet moment ?
> or something like this
> At least how can a line~ could be used for this purpose
>
> How can you use a line~ for smoothing ?

If I might say so, I think you are taking the wrong approach to your
problems.
Instead of smoothing out any rough edges, probably severely degrading sound
quality
in the process, you should try to find the source(s) of the clicks and
resolve those
problems. Please keep in mind that MSP after all is a programming language,
and
undesired clicks are symptoms of problems (bugs) in your patch. You should
rather
trap and remove such bugs than covering them up.

Here's a few tips on what to do and look for when debugging:

Encapsulate tasks in subpatches, and thoroughly test them. Isolate each task
in a
separate subpatch and test it. The best thing to do is to encapsulate as you
go
along, and do testing/debugging as you progress. If you make a huge patch
and only
start testing/debugging after having finished it, you are likely to be in
for a lot
more trouble than if you do quality testing while programming. The chapters
on
encapsulation and debugging in the Max manual are recommended reading. Also
Peter
Elsea has made a tutorial on debugging that can be downloaded from:

ftp://arts.ucsc.edu/pub/ems

Audio clicks are caused by sudden changes of numerical values. Here are some
suggestions of what could cause this:

1) Playback of sound files or buffers. If the sound file or buffer starts or
end with
a value different from 0 you'll get a click at the start or end of playback.
Use
line~ during recording and/or playback to ensure smooth fade-ins or
fadeouts. Also
check to make sure that there are no clicks caused by the sound file itself.
Make a
simple patch for playback (just a sfplay~ object and dac~) and listen to it.
If you
get clicks you should edit the sound file to get rid of them.

2) If you are using dynamic routing by means of gate~, select~ etc. you have
to
ensure that you don't get clicks when rerouting.

3) If you have encapsulated tasks in subpatches and mute these at some
stage, you
have to make sure that you don't get any clicks when muting or unmuting, and
also
that you don't get noise when the subpatch is muted (check out the pass~
object).

4) Garbage in - garbage out: If you use live feed of signal into the patch,
you have
to ensure yourself of the quality of the input signal. Also check for DC
offset of
the input signal.

5) Wave shaping synthesis can produce DC offsets (in case you use that). In
that case
you'll have to determine whether it is a problem, and if it is decide on how
to deal
with it.

6) Watch your levels and frequencies to avoid digital distortion or
aliasing.

7) If you use objects with a limited range of input, make sure that you
don't
trespass it. For example you should avoid dividing by 0. or usingpow~ to
calculate
fractional power for negative numbers.

If your patch allows for it, see if you can split it on the middle and test
if clicks
are caused by the upper or lower part. If it is caused by the upper part,
split that
in two and continue this way until you have located the source. Often this
saves you
time compared to searching step by step through the patch.

Good luck! Debugging is always a hassle.

Trond L.

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

Date:    Thu, 22 Apr 1999 10:29:48 +0100
From:    Jamie Bullock 
Subject: Re: Force Sensitive Resistors

Hi Michael,

Have you actually implemented this? If so, answers to the following would be
much appreciated:

- What is the resistivity (in Ohm-metres) of the foam?
- What thickness of foam was used between the electrodes?
- What were the approximate resistances (betwen the electrodes)  i) when the
foam was not depressed and ii) when the foam was fully pressed down?
- What sort of p.d. and current could you apply across/through the
terminals?
- Where can such a material be purchased on a 'domestic' budget?

Thanks in advance for answers to any of the above!

Cheers,
-Jamie Bullock

On April 21st, Michael Wieser wrote:

>If you would do some craftwork (?) put some pieces of the antistatic foamed
>plastic, which is used to transport Integrated Circuits between 2
>electrodes. If you press onto the 2 electrodes, the resitance of the
>antstatic-plastics goes down. Its not a 0,05% solution, but it works fine
>(and cheap)

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

Date:    Thu, 22 Apr 1999 12:08:44 +0200
From:    Peter Castine 
Subject: Re: the BBQ object (of desire)

On around 22-4-99 6:45, Nicholas Longo said something like:

><<>From:    Peter Nyboer 
>
><<>Peter "Is BBQ off-topic?" Nyboer
>
><<(with apologies to our wonderful vegetarian and vegan colleagues), etc.
>
>Actually, if you're in Berkeley (correct spelling) and hanging around at
>1750 Arch St. you don't have to take the bus to Oakland for breakfast.
>You're within walking distance of the world famous "Gourment Ghetto".
>Every other doorway along a mile long stretch of Shattuck Ave. is an
>eating establishment, including side streets.  The best (veggie) breakfast
>is Smokey Joe's Cafe, just south of Cedar and Shattuck.


     Hmmmmmmm. Breakfast.


For my money you can't beat breakfast in the Lindos Mare, about two km
from Lindos on the road to K=E1lathos.

Quark with fresh walnuts and honey. Side order of egg sunny side (this
goy takes bacon with it, despite tsuris over cholestorol from the
doctor). Fresh fruit and Greek cakes. Hmmmmm.

Cheers,

Peter -- who would rather be in Rhodos. Does anyone have an MSP external
that can do bouzouki playing Greek dances?

----------------- http://www.prz.tu-berlin.de/~pcastine/ -----------------
Dr. Peter Castine          | I am very pleased to announce that the
4-15 Music & Technology    | 26th International Computer Music Conference
                           | will take place in Berlin in the year 2000.
                           | We look forward to seeing you here!

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

Date:    Thu, 22 Apr 1999 07:24:55 -0400
From:    jmw/cmu 
Subject: Re: FSR

>Hi!
>
>Where? In Europa?

Sorry, I should've mentioned that I'm in the US (NY to be exact).

thanks,

john

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

Date:    Thu, 22 Apr 1999 04:26:28 -0700
From:    Carl Stone 
Subject: the BBQ object (of desire)

Oh-Oh. BBQ on the MAXList. Don't get me started.

Today's Palindrome: Marge lets Norah see Sharon's telegram

C  -----------------------------------------------------
A  INTERNET: cstone@sukothai.com      WELL: cstone
R
L  -----------------------------------------------------
 STONE      4104 24th Street #410
                      San Francisco CA 94114 USA
         -----------------------------------------------
                            WEB: http://www.sukothai.com

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

Date:    Thu, 22 Apr 1999 10:13:01 -0400
From:    Johnny DeKam 
Subject: Re: MAX Digest - 20 Apr 1999 to 21 Apr 1999 (#1999-122)

The Miro uses hardware based compression/decompression.

Anytime that a software program applies a "real-time effect" to a video
stream, (warping, color change, any raster manipulation) it is intercepting
the native CODEC of the stream, and applying the changes for display on your
RGB monitor... doing so bypasses the hardware, because the hardware can only
display streams in its native CODEC. (MPEG in your case)  Until the day when
processors can recompress the native CODEC in real-time, effects must be
rendered in non-real-time.

(unless your using a scan converter to steal your RGB display to output an
NTSC/PAL signal)

Johnny DeKam

http://node.net/

----------

> Subject: Full Screen Movieplus & Virtual Scratch
>
> I'm curious to know if anyone has had any luck getting the Rokeby
> (sp?) object "movieplus" to do warping full-screen (640x480) with a
> video capture board? The Miro DC30 seems to output the video fine,
> but when any of the scaling, warping, rotation, etc. is applied, you
> either get minimal line distortion or nothing at all. When using just
> quicktime on screen, the warping effects seem fine. Any ideas?
>
> I'm also cleaning up my "virtual record scratching" patch that I
> posted info about a few days ago with comments and so forth due to
> the great response I recieved. I'll probably end up putting it up on
> node.net's ftp soon.
>
> Thanks-
> Nathan

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

Date:    Thu, 22 Apr 1999 10:33:11 -0400
From:    David Bianciardi 
Subject: Re: sensor question, cont.

On 4/22/99 12:00 AM, Automatic digest processor wrote:

>
>Subject: sensor question, continued
>
>Thanks for the many suggestions regarding sensors for vocal data. There
>were a few questions about why no microphone. Its because I'd like to send
data at some
>points without making any sounds, but simply via mouth cavity shape
>changes. I guess that I could work around this by simply turning down the
amplitude
>at those points (!)

ok, how about having a very directional mic and a "sound source" that
emits very low or very high frequencies into the cavity, so that changes
to the cavity are perceived by the mic as modulations of the original
signal?  this way the vocalist doesn't have to be making any sound for
the mouth changes to register.  both the mic and the emitter could be
mounted on a little headset mic assembly...

does this make any sense?

David Bianciardi
tech@idrc.com

212.353.9087
212.353.3947 fax
______________________________________________
IDRC || 415 Lafayette St || NYC, NY 10003-7000

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

Date:    Thu, 22 Apr 1999 09:20:38 -0600
From:    Steve Anderson 
Subject: Re: MAX Digest - 20 Apr 1999 to 21 Apr 1999 (#1999-122)

         Reply to:   RE: MAX Digest - 20 Apr 1999 to 21 Apr 1999
(#1999-122)
>From:    jmw/cmu 
>Subject: Force Sensitive Resistors?
>
>I'm looking for a source of FSR & linear potentiometers ( ribbon
>controllers).

Try a #150551 Flex Sensor from Jameco Electronics  $10.95
800-831-4242    jameco.com
They are piezo segmented bend sensors for gloves, etc.
 Varies from 10k - 40k or, puts out voltage
in the mv range. We have used them for other applications.
For the ribbon-type controllers,.. I have had more luck with capacitance
sensing "sandwich" plates than resistance.
The conductive foam works ok, the "rebound" is slow, get the stiff stuff.

steve anderson
laser dreams

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

Date:    Thu, 22 Apr 1999 12:22:14 -0400
From:    "Mr. Jester" 
Subject: Digital click removal

>Date:    Wed, 21 Apr 1999 09:18:53 +0200
>From:    Roland Cahen & Ruth Sefton-Green 
>Subject: cliqs & klocs goweway!

>What kind of solution can you find to get rid of digital cliks ?
>Is there an existing anticlick MSP object ?
>One which would detect a steeper amplitude slope variation in a short
>delay preferably in a quiet moment ?
>or something like this
>At least how can a line~ could be used for this purpose
>How can you use a line~ for smoothing ?
>Roland

This depends on your source material - I assume you mean in live
recording/playback situations, because otherwise I'd say whip out Sound
Designer/Peak/(insert favourite audio editor here) and edit them out of
the soundfile yourself.

For live performance, the easy thing to do is to send the audio before you
record it through a *~ object - when you start recording, you immediately
send a line~ the message 0, 1 1 (from zero to 1 in 1 millisecond), with
the output of line~ patched to the right input of *~.  The message to stop
recording would first bring the line~ from 1 to zero, and then actually
stop the recording.

This assumes that the clicks are coming at the starts and ends of
sounds - if theyre coming from somewhere else I would examine the source
material youre sending MSP.  I am sure it would be possible to write a
declick~ object, but why would you need to?

The one drawback of the line method above is that you do get a pulsating
effect if you loop the sounds.  I tried doing something where MSP detected
whether the audio was naturally at the zero line (and whether it had come
from above or below) and only cutting off audio on a natural zero.  In the
time it took max to calculate a zero point and stop recording, however,
the audio, moving at 44.1 kHZ, versus max's 1 kHz, had moved away.  I
imagine it would be possible to write an MSP object that would do this
fast enough internally (it would have to be a modified sfrecord~ -
looprecord~?) - I havent tried.

Jer

  #  ##  #        Mr. Jester     |  mrjester@fledge.watson.org
 ##########         Jer Welter   |    jwelter@goucher.edu
#  | ** |  #    "this might just be the sit down
     <                   formal wake for reason"  --barkmarket

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

Date:    Thu, 22 Apr 1999 20:21:32 +0200
From:    Michael Wieser 
Subject: Re: Force Sensitive Resistors

Am/Um 10:29 22.04.99 +0100 schrieben Sie:
>Hi Michael,
>
>Have you actually implemented this? If so, answers to the following would
be
>much appreciated:
>
>- What is the resistivity (in Ohm-metres) of the foam?
>- What thickness of foam was used between the electrodes?
>- What were the approximate resistances (betwen the electrodes)  i) when
the
>foam was not depressed and ii) when the foam was fully pressed down?

I put this answers together, because all answer depends on the material and
the contact-area (sorry for _that_ answer...)
So this are not values, which can be repoduced in every combination. But
usualy the smallest value is in the 5 to 10kOhm range and goes up to
150kOhm for the material (8mm unpressed) I used.

I did some construction of this kind for an invisible "people enter room"
construction. For this problem it was enough to detect a resistance-change
in short time.

>- What sort of p.d. and current could you apply across/through the
>terminals?

Whats p.d?
Current is up to 1mA, but alos depends on the area of the foam. I would not
apply a voltage greater the 10 to 15 Volts and put a resistor with 4k7 in
series to the foam, so in the worstcase   that the current can`t be greater
the 2-3mA... (

>- Where can such a material be purchased on a 'domestic' budget?

Whats "domestic" (sorry, my old dictionary hasn`t it...)
If it means "low budget"- go to an Store, which sells Integrated Circuits,
I`m sure they will give you some pieces without paying. The other things-
it costs time, but nearly no money to build it.
I think, (in the worst case) you can buy it also by Jameco...

hth

>Thanks in advance for answers to any of the above!
>
>Cheers,
>-Jamie Bullock
>
>On April 21st, Michael Wieser wrote:
>
>>If you would do some craftwork (?) put some pieces of the antistatic
foamed
>>plastic, which is used to transport Integrated Circuits between 2
>>electrodes. If you press onto the 2 electrodes, the resitance of the
>>antstatic-plastics goes down. Its not a 0,05% solution, but it works fine
>>(and cheap)
>
>
Michael Wieser
m.k.w@magnet.at

Service and Audiodesign

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

End of MAX Digest - 21 Apr 1999 to 22 Apr 1999 (#1999-123)
**********************************************************