Primary General Discussion Area

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Primary General Discussion Area Steve Gibson 7/31/11 1:12 PM
This is intended to be this group's primary general discussion area.

A high-end portable device is necessarily a sophisticated system incorporating a high-voltage/high-current rechargeable battery system, a microprocessor control and management system with audio input and output, user-interface input and output, and battery management subsystems, a high-power audio amplifier, and an enclosure designed to focus and aim the system's generated sound.

Since each of these are subsystems in their own right, we have broken these out into their own discussions.

But this topic is for general discussion.
Re: Primary General Discussion Area steveg...@gmail.com 8/3/11 1:36 AM

Steve

Rather than using a parabolic reflector, why not use a pair (or triple) of tweeters fed as a phased array to get a directional beam?

Steve

Re: Primary General Discussion Area atn...@silentshadows.com 8/3/11 3:34 AM
Hi there Steve,

This has probably been pointed out by others, but just in case it managed to slip by, I wanted to make sure that I brought up the fact that you might have a naming issue with 'Portable Sound Blaster'.  I wouldn't put it past Creative Labs to get law happy and try to go after you for that one, since they do manufacture a 'portable' usb sound system, and the 'Sound Blaster' name has been theirs for quite some time.  There's definitely quite a difference between the intent of your Sound Blaster and theirs, but I thought it worth mentioning.

Anywho, keep up the good work as always :)

Jimmy
Re: Primary General Discussion Area Skip Pope 8/3/11 4:37 AM
I have tried several of these type devices to try and teach a dog to stop barking and the first limiting factor has been the trigger. I have always wanted to be able to record the barking and use that to trigger the unit as I have had problems with tuning the units to trigger only on the barking and not other noise. The dogs in my case are 150 feet away so the unit has to be placed close to them so this leaves me with the option of something that will reliably trigger the unit on a bark or have a way to remotely trigger the unit. I would love to be able to record the barking and use that to trigger the unit reliably. Any thoughts on this option for your unit?
Re: Primary General Discussion Area mark moore 8/3/11 6:20 AM
Hi Steve,
   I am new to building electronic devices so it would be great if someone could list the tools that will be required to complete this project. I have a few basic tools already, but I am sure there are some I am missing.

Thanks!
Re: Primary General Discussion Area Steve Gibson 8/3/11 1:15 PM
Hi Steve,

From the bit of looking at that approach I did, it appeared that the inter-transducer distance needed to be a small fraction of the wavelength.  But at audio frequencies where we want to work, the wavelengths are pretty short ... much shorter than the diameters of the tweeters.  Otherwise I was thinking that it was definitely worth exploring.

If you Google "Parametric Speakers" you also get a bunch of interesting links.  :)
Re: Primary General Discussion Area Steve Gibson 8/3/11 1:18 PM
Jimmy...

Yes, it's been mentioned a number of times.  And it's a worthwhile point.  But I believe I'm okay, since I am describing what it is and Creative Labs doesn't own those words.  The fact is, unlike "Exxon" or "Xerox" or "Kleenex" -- all which are really GOOD trademarks since they are not simply descriptive, "Sound Blaster" was never a good trademark since it IS highly descriptive.  That fact dramatically weakens the level of protection they are able to obtain.
Re: Primary General Discussion Area Steve Gibson 8/3/11 1:21 PM
Yes Skip.

My design will be able to operate in both "make sounds" and "record sounds" modes, since a dynamic speaker can also act as a microphone.  And I HAVE been thinking that with the wonder power of an ARM Cortex-M3 processor, we ought to be able to get a VERY good and highly refined (low false alarm rate) "dog bark discriminator".  So the unit would be listening for barks in "microphone mode".  And as soon as barking began it would switch around and send out training blasts.
Re: Primary General Discussion Area Darryl Quinn 8/3/11 1:38 PM
Hi Mark,
I'll take a first stab at tools (FWIW)...

- a decent solder station (not a Radio Shack iron)
- solder (resin core NOT ACID CORE)
- desoldering bulb or desoldering wick or desoldering station
- fine tweezers
- small diagonal cutters (for trimming wire leads after soldering)
- flux remover spray (to have nice clean PCB's after soldering)


Re: Primary General Discussion Area mark moore 8/4/11 5:59 AM
Thanks Darryl, I will go pick up what I am missing.
Re: Primary General Discussion Area Steve Gibson 8/4/11 1:41 PM

Exploring "Plan B":
Gang...

I have been haunted by the idea of ultrasonic beams "self-demodulating" in mid-air to produce sonic results.

If the wavelength of the sound being generated is smaller than the effective diameter of the sound generator, then "planar wavefronts" are propagated from the emitter, or emitter array.  This means that although we cannot "aim" sonic frequencies with emitter arrays due to their long wavelengths relative to the diameter and/or separation of emitters, we CAN potentially aim ultrasonic frequencies.

The trouble is that I have wanted to create a multipurpose device to experiment with birds in addition to canines ... but bird hearing starts dropping off around 8500 hz, so definitely sub-ultrasonic.

However, it turns out that if ultrasonic frequencies are amplitude modulated, some non-linear properties of air propagation can induce the ultrasonics to "self demodulate" and produce what are essentially the beat frequencys (sum and difference) of the carrier and modulation.

We all remember how a slide rule works.  It's using addition upon a non-linear (logarithmic) scale.  It turns out that the AIR can be induced to act non-linearly because locallized sound pressure creates heat and a change in temperature, and the rate of propagation of sound through a medium is a function of temperature and pressure.  So it's possible to induce an ultrasonic beam to interact with itself!  What this means, practically, is that we can get both the directionality of high-frequency emission and sub-ultrasonic resulting frequencies.

And THAT is interesting because there appear to be powerful and interesting piezoelectric transducers (audio tweeters) available for just a few dollars each!


I like the first one (the Goldwood GT-1005) because it's only $2.45 (or $1.99 if we were to do a big group purchase in the future) and each one can crank out 50 watts RMS with a frequency response from 3500 to 26khz and 94 dBSPL sensitivity.

I like the second one (the Goldwood GT-400CD) because it's $3.84 each (or $$2.72 at 50 or more), has a power handling capacity of 100 watts RMS and a frequency response of 1800 to 30khz with a 92 dBSPL (1W/1M).

That second one also has a smaller outside diameter of 2-7/16 inchs, so an array of them could be mounted at 2.5" centers.

And lastly... One of the annoyances I've had with my first-pass approach was that the batteries had excessive amperage capability, but low-voltage relative to the need of a largely resistive 4 ohm load.  So it was necessary to gang up three 5-cell batteries in order to get 55.5 volts to switch across the tweeter.  I have started receiving some of these batteries, and although they are lithium, these suckers are HEAVY.  Three of them is going to weigh a lot... even before we add everything else.  :(

But when we're driving a gang of piezo tweeters we might be able to connect a large (like a 4 x 4) array of them all in parallel with a very low input impedance step-up transformer to drive the transducer array.  That might allow us to operate with a single five or six cell battery pack, pulling a LOT more current from it, yet needing only one.  That would make managing the battery much easier, use the battery's available current, and lighten the overall device.

And finally, that first $2.45 piezo transducer look SUSPICIOUSLY like the high-power ultrasonic emitter that http://www.amazing1.com is offering for $29.95!...  (The photos are of 2x2 and 4x2 arrays):

ppf40                    ppf40
Anyway, just an update on what I've been thinking.  :)

I've ordered a bunch of both of those piezo tweeters to see what they can do.

smg-sig2

Re: Primary General Discussion Area Danial Bulloch 8/4/11 2:27 PM
Another name I've liked is "Sonic Disruptor". It has a sci-fi feel and has been used in a few different books and TV shows. It sounds cool, but is also an accurate description of what it does. It is a sonic tool to disrupt unwanted behavior.
Re: Primary General Discussion Area Bill G 8/4/11 6:52 PM
Hey, Steve!

Thanks for your time on this but for those of us who don't need a
portable solution(the neighbors aren't moving) what's your take on
this: http://www.amazing1.com/pest_control.htm ? (scroll down to the
"Canine Controller")?

Although the output(130dB @ 30cm) isn't really that impressive, the
size, weight, auto-triggering and adjustable output frequencies are
attractive.

Whaddya think? Would it work? Is it worth the money for the kit?

Thanks,
Bill
Re: Primary General Discussion Area Steve Gibson 8/5/11 10:42 AM
Hi Bill,

My thinking has been heading in this direction (among others) because so many of the people I am hearing from (and all three of the close friends I have previously written about) are in fixed locations with fixed-annoyance neighboring dogs.  So the idea of an automatic "dog bark triggered" solution makes a great deal of sense. And it does seem that a wayward canine would quickly learn to associate their barking with being blasted by a distracting loud and annoying sound. (During the period that I was purchasing existing commercial "bark stoppers" my buddy finally tried aiming THREE AT ONCE at his neighbor's annoying little yappy dog.  The dog stopped barking and shook his head like he had water in his ears... and quickly went back inside the house.)

I have a few thoughts:

● The Information Unlimited (Amazing1.com) canine control device exists NOW and all I have is plans and intentions... and no committed time line and I'm not in a hurry.  I'm ALWAYS disposed to coming up with the optimal solution, rather than a quick solution.  So there's that.

● I have already (yesterday) ordered their PPF4K, Phasor Pain Field Generator Kit/Plans for $229.95, because I want to see how loud these things really are, and because I am suspicious that they are simply using THIS readily available piezoelectric tweeter (enable image display to see it):

Goldwood GT-1005 Wide Dispersion Piezo Tweeter
Doesn't that look suspiciously like what Information Unlimited is offering in various configurations?  It's interesting to me, since these tweeters (above) are available for $2.15 (I bought 20) from Amazon and Parts Express.  Information Unlimited charges $29.95 for these individually.

Unfortunately they don't offer to see a kit without the tweeters, or only a circuit board(s).

● Because I want to survey the territory, I just purchased the plans-only for that "Canine Control" device for $9 to see what they were doing.  It's actually two separate units, a microphone/filter/counter/controller and a separate quad-transducer blaster.  One of the gadgets I purchased for my buddy to try was also supposed to be "dog controlled", but it either tended not to "fire", or to be misfiring.  The trouble with "teaching" and "training", is that only reliable and consistent training feedback will result in training.  If some barking never produces any feedback, or (even worse) if feedback is produced when the pooch is NOT barking, then the dog won't learn to associate the two.  The schematic of the Canine Controller reveals an extremely simple filter that could not be very discriminating.  It looks like a high-pass filter followed by a Schmitt trigger.

So....

My HIGHLY TENTATIVE plan is:

I have purchased 20 of this (above) type of inexpensive piezoelectric tweeter, and 30 of another (only slightly more expensive type for $3.43), because I want to experiment with using them individually and in large phased arrays, and also because I want to push them to their limits and probably destroy some.  At $2.45 each, who cares?

I want to see whether I can use these as BOTH a microphone and a speaker.  So that a single "device" could function to both hear the "bark" and respond to it. And, of course, any solution I came up with would have a microcontroller at its heart and it would be recording and analyzing all incoming sound, examining not only the loudness envelope, but probably performing a fast Fourier transform (FFT) to analyze the spectral content to determine whether it really WAS a dog's characteristic bark.

So... Since the microprocessor is only $30, and the tweeters are only $2.15 each, and since we would be using a VASTLY simplified amplifier to drive a highly capacitive/reactive load (the piezo transducer) ... I'm hopeful that we might be able to arrive at an extremely affordable solution ... with all the power of an ARM Cortex-M3 microprocessor making the device truly SMART.

But, once again... NONE of that is now, today, or probably even soon.

So you could grab what the Information Unlimited folks have to offer now... and if it doesn't prove to be workable, you'll already have the "output end" all setup and ready to go when I create a much more sophisticated trigger for it.  :)

(And if you DO decide to get the Canine Controller... PLEASE share your results with everyone here!)

Re: Primary General Discussion Area Skip Pope 8/5/11 11:08 AM
I have the Amazing1 unit and in my case it is located about 75 feet from the German Shepard's and will not trigger on the barking dogs, but is always triggered by motorcycles and trucks going by on the road 400 feet away. I have tuned and tuned on this unit without satisfactory results. Beyond that there does not seem to be a frequency that will bother these dogs at this distance although I have not finished exhausting all settings yet. I have been working with this unit for about 4 months now.
The trigger problem is the first problem I have been thinking about solving by recording the barking and trigger by matching the sounds somehow as when the unit is located far from my house standing out there triggering by hand is not a good alternative.
Re: Primary General Discussion Area Steve Gibson 8/5/11 1:14 PM
Hi Skip...

Based upon the schematic I looked at an hour ago (a high-pass filter feeding into a integrating schmitt trigger), I'm not surprised by your real-world experience with the trigger, though I am sorry to hear that at 75 feet away the canines are not being annoyed enough (or made curious enough) to stop barking.

FWIW, I would pitch the system JUST above your hearing and ignore the "warbling" business entirely.  I'm not yet sure what the frequency response is of these drivers, but whatever it is, it would tend to start dropping off at higher levels.  So you want as much sound pressure output as you can get without it bothering the humans in the area.  Also... the driver circuitry shown in the schematic is going to be rather frequency-sensitive.  The guy is using an inductive flyback approach to kick the voltage across the piezo driver up above the battery level.  But its performance is going to vary a lot with the frequency.  I'll know a LOT more once I have had the chance to build one and see what it's doing.  :)

But in any event... my hunch is that we'll be able to make an extremely good and highly discriminating "bark back" trigger that won't be fooled at all by motorcycles, lawnmowers, or other environmental noise.  Dog barks, no matter the size of the dog, are extremely characteristic and should have a clearly recognizable volume envelope as well as a characteristic spectrum.  And, based around the $30 ARM development board, it shouldn't cost much either!

Re: Primary General Discussion Area Bill G 8/6/11 9:00 AM
Hey, Skip!

Thanks for the feedback, you saved me the trouble and expense of
trying it for myself. I already tried this one: and, while the
detection was good it didn't produce enough output to dissuade the
dogs from barking while standing 20' away from the unit.

Amazing this problem is so prevalent, I stumbled onto this site while
searching: http://www.barkingdogs.net/index.shtml

Thanks for the time and effort, Steve, I think I'll stick with you and
the group for now and see what comes up.

Best,
Bill


Re: Primary General Discussion Area Bill G 8/6/11 9:03 AM


Looks like the link for the unit I have didn't come through, here it
is: http://www.ultimatebarkcontrol.com/ds_pro.htm#page=Main-Tab
Re: Primary General Discussion Area Skip Pope 8/6/11 9:12 AM
Yup, I have tried that one also.
Amazing how much money I have spent trying to enjoy my porch and property. Instead I have been trapped inside my own house due to the fact that someone keeps there dogs in a small fenced in area where they bark constantly at anything that moves.
Re: Primary General Discussion Area Mat Lee 8/6/11 9:42 AM
That episode like others quickly became one of my favorites. Its like a weird nerdy bedtime story uncle Leo and uncle Steve tell before bed. Anyways I'm new to this sort of stuff but eager to learn from the masters. I live in Montana where this could have applications with bears and other larger wild life. Plus people like their big rots and Pitt's up here so I'm interested to see how well this works in aiding training.
Re: Primary General Discussion Area Steve Gibson 8/6/11 11:07 AM
Further to your comment about "tuning"...  (turn on images to see the chart below)

I found the frequency response curve of the tweeters that I'm betting the Information Unlimited folks are using in their various "painfield" generation products:



Note that this sucker peaks strongly between 8 and 9 kHz.  And I mean strongly!  Given that each 3dB of sound output is a DOUBLING of output power, the difference between its peak of 105 dB versus its typical 85 dB output power, being 20 dB, is an output power differential of 4.3 times!

This is, of course, the mixed blessing of piezo transducers... they are just SO mechanical that their frequency response tends to look like the Rocky Mountains!

The problem with THIS is that 8 to 9 kHz is definitely within the audible range of humans.  It'll be a high pitch, but it'll certainly be audible.

Re: Primary General Discussion Area Lane Slabaugh 8/6/11 11:51 AM
Not seeing the chart here Steve...I can see all the other images you've posted...did you not attach it?
Re: Primary General Discussion Area Steve Gibson 8/6/11 12:11 PM
Ah! Live and Learn!  It embedded the LINK to the image instead of the image itself... and I hosted the image on my own local server for copy/paste into the document!  I'll repost it with a link on GRC's server.  Thanks for the heads-up Lane!!
Re: Primary General Discussion Area Steve Gibson 8/6/11 12:15 PM

Here's the Piezo Transducer's Frequency Response Chart

Re: Primary General Discussion Area Steve Gibson 8/6/11 1:23 PM
Really interesting chart of comparative animal hearing ranges!:

Species Approximate Range (Hz) 
human 64-23,000
dog 67-45,000 
cat 45-64,000 
cow 23-35,000 
horse 55-33,500 
sheep 100-30,000 
rabbit 360-42,000 
rat 200-76,000 
mouse 1,000-91,000 
gerbil 100-60,000 
guinea pig 54-50,000 
hedgehog 250-45,000 
raccoon 100-40,000
ferret 16-44,000 
opossum 500-64,000 
chinchilla 90-22,800 
bat 2,000-110,000 
beluga whale 1,000-123,000
elephant 16-12,000 
porpoise 75-150,000
goldfish 20-3,000 
catfish  50-4,000 
tuna  50-1,100 
bullfrog  100-3,000 
tree frog 50-4,000 
canary  250-8,000 
parakeet  200-8,500 
cockatiel 250-8,000 
owl  200-12,000 
chicken  125-2,000 
Re: Primary General Discussion Area HappyHappyMe 8/7/11 1:37 AM
Hi Steve,

Regarding your "Plan B, and ultrasonic beams"...   Have you seen this
TED Talk by Woody Norris.

http://www.ted.com/talks/lang/eng/woody_norris_invents_amazing_things.html

Ed McKiver


On Aug 4, 1:41 pm, Steve Gibson <steve.gib...@gmail.com> wrote:
> *
> *
> *Exploring "Plan B":*
> Gang...
>
> I have been haunted by the idea of ultrasonic beams "self-demodulating" in
> mid-air to produce sonic results.
>
> If the wavelength of the sound being generated is smaller than the effective
> diameter of the sound generator, then "planar wavefronts" are propagated
> from the emitter, or emitter array.  This means that although we cannot
> "aim" sonic frequencies with emitter arrays due to their long wavelengths
> relative to the diameter and/or separation of emitters, we *CAN* potentially
> aim ultrasonic frequencies.
>
> The trouble is that I have wanted to create a multipurpose device to
> experiment with birds in addition to canines ... but bird hearing starts
> dropping off around 8500 hz, so definitely sub-ultrasonic.
>
> However, it turns out that if ultrasonic frequencies are amplitude
> modulated, some non-linear properties of air propagation can induce the
> ultrasonics to "self demodulate" and produce what are essentially the beat
> frequencys (sum and difference) of the carrier and modulation.
>
> We all remember how a slide rule works.  It's using addition upon a
> non-linear (logarithmic) scale.  It turns out that the AIR can be induced to
> act non-linearly because locallized sound pressure creates heat and a change
> in temperature, and the rate of propagation of sound through a medium is a
> function of temperature and pressure.  So it's possible to induce an
> ultrasonic beam to interact *with itself*!  What this means, practically, is
> that we can get both the directionality of high-frequency emission and
> sub-ultrasonic resulting frequencies.
>
> And THAT is interesting because there appear to be powerful and interesting
> piezoelectric transducers (audio tweeters) available for just a few dollars
> each!
>
> http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=270-011&scq...http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=270-069&scq...
>
> I like the first one (the Goldwood GT-1005) because it's only $2.45 (or
> $1.99 if we were to do a big group purchase in the future) and each one can
> crank out 50 watts RMS with a frequency response from 3500 to 26khz and 94
> dBSPL sensitivity.
>
> I like the second one (the Goldwood GT-400CD) because it's $3.84 each (or
> $$2.72 at 50 or more), has a power handling capacity of 100 watts RMS and a
> frequency response of 1800 to 30khz with a 92 dBSPL (1W/1M).
>
> That second one also has a smaller outside diameter of 2-7/16 inchs, so an
> array of them could be mounted at 2.5" centers.
>
> And lastly... One of the annoyances I've had with my first-pass approach was
> that the batteries had excessive amperage capability, but low-voltage
> relative to the need of a largely resistive 4 ohm load.  So it was necessary
> to gang up three 5-cell batteries in order to get 55.5 volts to switch
> across the tweeter.  I have started receiving some of these batteries, and
> although they are lithium, these suckers are HEAVY.  Three of them is going
> to weigh a lot... even before we add everything else.  :(
>
> But when we're driving a gang of piezo tweeters we might be able to connect
> a large (like a 4 x 4) array of them all in parallel with a very low input
> impedance step-up transformer to drive the transducer array.  That might
> allow us to operate with a *single* five or six cell battery pack, pulling a
> LOT more current from it, yet needing only one.  That would make managing
> the battery much easier, use the battery's available current, and lighten
> the overall device.
>
> And finally, that first $2.45 piezo transducer look SUSPICIOUSLY like the
> high-power ultrasonic emitter thathttp://www.amazing1.comis offering for
> $29.95!...  (The photos are of 2x2 and 4x2 arrays):
>
> [image: ppf40]                    [image: ppf40]
> Anyway, just an update on what I've been thinking.  :)
>
> I've ordered a bunch of both of those piezo tweeters to see what they can
> do.
>
> [image: smg-sig2]
Re: Primary General Discussion Area hane...@gmail.com 8/8/11 5:13 PM
put this on Twitter  also putting it here:

@sggrc For bird prob, check out diydrones.com. Birds may fear it as a predator or you could put the sonic payload up away from the humans.

potential 21st century scarecrow tactic.  For sonic delivery maybe a nearby roof top would be less disruptive to people than transmitting from the ground.
Re: Primary General Discussion Area rickhu...@att.net 8/11/11 12:42 AM
Steve,
 
Yes, you surely were blessed with the gift of high tech diagnosis ( which I was not ).
 
Please advise on best suggestion for quieting a nuisance dog in a 30 foot outdoor run.  Would you try the Canine Controller for a 30 day rental at $75 ?
 
What in your opinion is the most effective at present ?
 
Here's hoping you will offer a viable solution for all of us !!
 
Thanks--Sam
Re: Primary General Discussion Area Rick Humphreys 8/11/11 12:42 AM
Re: Primary General Discussion Area Irvin Velazquez 8/11/11 1:07 AM
Master Gibson, I do enjoy every week your podcast of security now, I want to be part of your sound blaster group. well you see I am in Mexico, and there is a pool, the problem is that every morning the birds are on the roof and their feathers every day hit the pool not to mention their pup. I want to use your device and record the results.

Irvin 
Re: Primary General Discussion Area Steve Gibson 8/11/11 11:22 AM
Hi Sam.

I don't yet have any experience with any of the Information Unlimited devices.  I do have one of their "painfield generation" kits on order, though.  So I should know more eventually.  I'll be sharing everything that I learn here ... so please keep an eye on this group.  :)

Thanks!
Re: Primary General Discussion Area LockPro 8/14/11 7:20 AM
Hi Steve:
Like others, I loved the "Dog Killer" podcast. The device reminded me of my youth when I worked as a burglar alarm installer in the late 60's and early 70's. Back in those days alarm panels were powered by the old 1.5 volt dry cell batteries that were about as big around as a soda can and a little taller. Remember those? Anyway, your project reminded me of 2 alarm systems that were used back then. The Kurux Kurdler and the Sonaguard. The Sonaguard looked like a big portable stereo system. The speakers had metal cones to handle the high sound output when the system detected an intruder. When it was turned on the speakers put out an audible tone and it functioned much like an ultrasonic motion detector, except it was audible for deterrent purposes. In fact, the sticker on the door said something like "Hear that sound? It is the burglar alarm system". Anyway, when motion was detected the speakers were then used to output a VERY loud noise that the literature described as "loud enough to cause nausea and compel the intruder to swiftly leave the area". The Kurux system was similar except it was permanently installed and used the bullhorn type speakers. Having tripped both systems in my days as an installer I can tell you they were quite effective if you were without ear protection.

I'm looking forward to building one of your devices to see if it can be used as a coyote repellant on our farm.

Best Regards
Jon Payne Sr.
unk...@googlegroups.com 8/14/11 7:38 AM <This message has been deleted.>
Re: Primary General Discussion Area Steve Gibson 8/19/11 10:00 AM
Eureka!!

During every free moment, I have been reading, researching, and reading everything I can find (and understand) about the physics of acoustic impedance matching and waveguide transmission in air.  I've been working to develop an intuitive understanding of the way moving membranes couple their energy to the air, how pressure waves in that air moves through waveguides of various shapes, how the air pressure waves behave upon emerging from the end of the waveguide (horn) in terms of the impedance mismatch at the horn's opening and the shape of the wavefronts, which affects the directivity of the sound.

The goal, of course, is to be able to "beam" high-intensity sound over long distances to a remote location.  As always, I don't just want to do it.  I want to do it the best way possible.

This morning I stumbled upon a pair of fantastic PDFs (part #1 and part #2) explaining Horn Theory in language and math that's far more down-to-Earth than anything I have found before.  I wanted to document the find, and also share it with anyone who might also be interested in understanding one aspect of the fundamental theory that future solutions will be based upon.  :)

The original source material links:

Both PDFs merged into one and saved on GRC's server for safety and posterity:

Re: Primary General Discussion Area tz 8/19/11 11:01 AM
There might be a lower-tech solution.

If you want to go steampunk - a bit literally - have you considered train horns?

You can use a paintball compressed CO2 cylinder (they can go 100psi+) and something like a train horn, though I wouldn't know how to get the diaphram to resonate at ultrasonic frequencies.  I do know that they will easily do 150dB in the audible range (having both 34db in-ears and 25Db over my head and pointing it away from me last time I tried).

If you google "train horn" you can find some for sale and the wikipedia article that explains it..  Even the small paintball cylinders could go several minutes if not longer - more than necessary and you can get refills at paintball places.

Re: Primary General Discussion Area Steve Gibson 8/20/11 8:20 AM
TZ,

Similar compressed-air-driven horns are also available as handheld small boat horns. And they are, indeed, VERY loud.  I have little doubt that blasting such a horn at a nearby dog would silence it, at least briefly. And doing so to a tree full of loudly squawking crows would doubtless cause them to take flight and abandon their roosts. So you're right that a $12.95 "solution" exists.

I place "solution" in quotes above, though, because these horns are specifically designed to command the attention of every human being within about a half mile ... and at that they are also quite effective. What I'm hoping to obtain is a far more selective solution that would disturb no people and, in fact, would go unnoticed by anyone other than the intended animal(s).

/Steve.
Re: [PSB] Re: Primary General Discussion Area Guillaume Auclair 8/20/11 9:05 AM

Hello everyone

I have to add my opinion on this one 

The device , I think absolutely has to be unnoticed by humans,
in my case  I'm thinking about the many many times the neihbor's dog is actively barking through the night, by blasting that sound I would'nt want to wake the others on the street who are NOT awaken by that vocal dog....

What would also be mandatory for me is that the device could be adjusted so that it would "alter bird's flight pattern " as the pdk did 40 years ago ,
and , also adjustable for thoses times where the neihborgs left their 16 years old boy at home for a weekend and the brilliant  "de-b oned" young man decided to play with fireworks at eleven and a half with his friends on a Friday night, + the police would not care to come and have  a look for such an insignificant disturbance ....
For thoses times to be human disturbing it would be very nice.

I would alsto like it to be portable, with one hand if possible, and highly directionnal, ...
But that's my needs...

Re: Primary General Discussion Area Thomas Trostel 8/27/11 9:47 AM
Steve,

Have you looked yet at what modulation scheme you want to use for your "hypersonic" signal?  I find reference to using DSB-AM modulation but that it suffers from heavy distortion.  Have you looked at doing LSB?  Just wondering.  if you had gotten any farther than me.

On an off hand note if the volume were kept down .... and modulated correctly that would make a heck of a halloween prank.  You could beam voices and sounds at your visitors that nobody else could hear!  

Thanks

Tom

PS:  Don't blame me if you start hearing things ... its probably your neighbor with a modified portable sound blaster ;-)
Re: Primary General Discussion Area Damage 8/27/11 3:31 PM


On Saturday, August 27, 2011 12:47:50 PM UTC-4, Tom wrote:
On an off hand note if the volume were kept down .... and modulated correctly that would make a heck of a halloween prank.  You could beam voices and sounds at your visitors that nobody else could hear!  



I love this idea!
RE: [PSB] Re: Primary General Discussion Area Rick Humphreys 8/27/11 5:10 PM

What is the best  ultrasonic device available for a neighbor’s barking dogs – big time nuisance ?

 

Thanks for any suggestions--Rick

 

From: portable-so...@googlegroups.com [mailto:portable-sound-blaster@googlegroups.com] On Behalf Of Damage
Sent: Saturday, August 27, 2011 5:32 PM
To: portable-so...@googlegroups.com
Subject: [PSB] Re: Primary General Discussion Area

 



On Saturday, August 27, 2011 12:47:50 PM UTC-4, Tom wrote:

On an off hand note if the volume were kept down .... and modulated correctly that would make a heck of a halloween prank.  You could beam voices and sounds at your visitors that nobody else could hear!  




I love this idea!

Re: Primary General Discussion Area robert...@gmail.com 8/31/11 5:05 PM
Hi Steve, Love Security Now, GRC.com and Owner of Spinrite.  I'm excited about this project.  I was wondering if, for the casing, we could use 12" pvc piping which we could cut to whatever length suited us best.  With fittings we could even get fancy on the design.  As a former plumber I notice, and am amazed by, how many things are built out of plumbing materials.  Hope this helps.

Rob
Re: Primary General Discussion Area g8kb...@googlemail.com 9/21/11 6:09 AM
Hi Steve.

Have you seen this?
http://ubeam.com/about/

Cant help wondering about *alternative* uses, or just how efficient (or otherwise) it is for their intended purposes.
No idea what sort of frequency it uses.

Keep up the good work with all things GRC, SN in particular, and many thanks for Spinrite.  It's got me out of a hole a few times now.  As has the snippets of knowledge (you've probably forgotten more than I'll ever know) gained from listening to SN over the years.

Oh yes, that mBed ARM prototyping kit, has so much potential for many other things.  I did know about it, but your PSB project has re-peaked my interest.   I just need the time to play now.

Best Regards.

Dave G8KBV (Leo should know by now what that is all about!)


Re: Primary General Discussion Area Jonathan Fry 9/27/11 2:05 AM
Phased Array and/or Parametric Array for Directional Beam Forming
would be an interesting approach.

http://en.wikipedia.org/wiki/Beamforming

http://en.wikipedia.org/wiki/Parametric_array

http://casa.colorado.edu/~danforth/science/sonar/sonar1.html
(Acoustic Applications of Phased Array Technology)

http://dspace.mit.edu/handle/1721.1/7987     (Parametric Array as an
Audible Sound Source, Link to page with the PDF's)



Re: Primary General Discussion Area bloc...@hotmail.com 11/2/11 3:19 AM
Hi Steve Gibson

Could your Portable sound blaster be used at a distance like 200 or so meters to scare away birds, this would be a useful here in Australia in our wide open spaces. where my parents are planting crops, not feeding birds. If not what can I change to scare away the 22.

Regards

Alistair clark      from Gingin Western Australia
Re: Primary General Discussion Area Big_Al 11/4/11 1:21 AM
Steve, Found this dog chaser in a local mail order magazine and thought it may interest you.
Re: Primary General Discussion Area craig....@gmail.com 11/17/11 5:14 AM
This may not be properly suited for this area but it is "general discussion" after all.

Check out last weeks Big Bang Theory (S05E09 - The Ornithophobia Diffusion) in which Sheldon must conquer his fear of birds.  At one point he pulls out a PSB and I couldn't help but thing of Steve.  It was a really funny episode.

Here's a You Tube link to just the PSB scene: http://www.youtube.com/watch?v=xZv8c7VREPY

I encourage you to watch the whole episode if you can.  It's really quite hilarious.


On a side note, PSB will always be PDK to me.  That episode of SN was awesome!  I hope it's rerun again this year as it was last year, otherwise I think I'll just have to listen to it again anyway. :)
Re: Primary General Discussion Area Mat Lee 11/18/11 7:31 AM
I totally saw that last night and was thinking the same exact thing. Great stuff!
Re: Primary General Discussion Area Tony Williams 12/26/11 4:10 PM
3 micro-computers you can use everyday

Interesting single board computers

http://nwlinux.com/3-micro-computers-everyday/
Re: Primary General Discussion Area RM 7/10/12 5:05 PM
 Steve and group:
Follow the APPLE.... they combined good tech in a beautiful package. Be like Steve Jobs and make sure this thing ROCKS! in more than a technical sense. Make it wonderful. Everybody made tablets, but Apple made it rock. I bet someone here is an artist in plastic molding or fiberglass.

Raymond
Re: Primary General Discussion Area Boilerbots 12/1/12 4:06 PM
Hello Steve,

I listen to your show all the time and I have some experience that you might want to consider. I hope this message doesn't end up too long and get skipped over.

I am a 39 year old Computer and Electrical Engineer professional, before I graduated college I worked in live audio to earn money and have fun. I have been dabbling in sound engineering projects for a very long time. I would like to give you some feedback and advice after listening to the most recent show.

Human range of hearing..... it is true that as we age we loose the higher frequencies but that doesn't mean we have all lost it. As I stated, I am 39 now and have spent a great deal of time operating large and very loud PA systems. Before I did that I could hear frequencies up to about 24KHz and it was always rather annoying. Now in my older age I am still able to hear up to at least 20KHz, yes I could hear Leo play that 18KHz tone from a podcast over blue-tooth into my car stereo while driving to work and it was very uncomfortable.

Why does this matter? Let me try to keep it short but it certainly pertains to this groups topic. I purchased a house 2 years ago here is the Silicon Valley. What was nice is that this house was on the edge of the city and thus had more room to my neighbors. After I moved in, one of the first things I noticed was this crazy annoying high frequency chirping noise that I could hear the minute I stepped outside or opened a window. This noise was not that loud from my driveway but it got into your head like it was going to melt your brain.

It wasn't hard to track it down because it was so loud. I found what appears to be a piezo tweater mounted firing into a parabolic reflector on my neighbor's roof (you see where I am going with this). I go over to have a talk with my new neighbor and it turns out that he is a retired engineer from HP and the people on the other side of the fence behind his house have an annoying dog. He was driving this tweater directly from an HP signal generator in a pulsing mode with the primary frequency set at about 18KHz.

I told him that this was very annoying, was really hurting my brain and I fear that my new born son might sustain some mental or hearing damage from this constant bombardment from his acoustic device. He wasn't inclined to stop because the neighbors dog was keeping him awake but his noise device was also causing me pain. Also I could not hear the dog that he hears. I figured the best option was to reason with him, he is a fellow engineer, so I told him that I was listening to your podcast about PDK and would help him build something better. In the mean time he turned the frequency up to slightly above 20KHz where it no longer bothered me at least. I can still tell when the device is active because the "attack" time when the pulse starts cause an acoustic "click" to be emitted from the tweater. Perhaps the oscillator is not actually working at this frequency but I only care about my own ears at this point.

Short lesson, don't create a new problem trying to eliminate another. I am telling you that his single tweater in a parabolic dish aiming probably 170 degrees away from my house from a roof over a fence lined with trees was very painful inside my own house with a window open.

When you first proposed this new project you where talking about using an ultrasonic beam that can result in an audible frequency that only can be heard where two  beams converge. The resulting frequency is the difference between the two beams. I like this approach for several reasons.

One, the only energy off axis is not audible if we keep it above 24KHz.

Two, speakers tend to form narrower beams with increasing frequency.

Three, It is directional by nature.

One example you can find is on Kickstarter, the project is called "soundlazer". Perhaps we can acquire some knowledge from that project. I have nothing to do with Soundlazer and am not endorsing it.


Addressing your new love for the MSP430. I have been using microcontrollers for a long time to drive motors. Something you should consider when selecting one is the output frequency vs. resolution of the PWM timer/generator. If you want to create high frequency audio you are going to need a high frequency source. If you're primary system frequency is something like 8MHz and you set the period register to 512, then that gives you 15.625 KHz, or 8 bits goes up to 31.250 KHz. This should be adequate for a straight up frequency blaster but I don't think it is good enough for the ultrasonic beam idea. Tricks can be played but it certainly would be easier to stick with a higher clocked processor. The ARM will also make it easier to do signal processing for bark detection by using standard 32 bit C libraries (fixed point of course).

I have an STM32F1 eval board and would love to develop a parallel project to this but like you I also have many irons in the fire. Even a Raspberry Pi would be a great little board for this project, $35 and you have a full linux computer with audio output.



Re: Primary General Discussion Area Dave Calhoun 12/4/12 11:05 PM
As you can imagine I'm in this forum because of my neighbors barking dogs that limit the use of my own back yard. Currently I'm using a couple of outdoor radio shack speakers, an Advent 300 amplifier and an ipod playing a 16khz tone. With it turned up to full volume the dogs seem annoyed and generally walk to the other side of the yard. I would like something more dedicated and something with more power. 

I found this forum, like many others, due to the podcast (which my father told me about). I have two questions. 1) is there a product that can be purchased right now or soon? I don't have the ability to make my own. 2) if not, what is the best alternative?

Thanks.
Re: Primary General Discussion Area Steve Gibson 12/6/12 9:03 AM
Hi David...

It appears that I never replied to your note... until now.  Sorry.

You're only a bit early.  At some point -- just as soon as I'm able to get everything organized -- I'll be making a formal call for people who have a need.  That'll give me some sense of scale and allow me to choose the best approach.  But I have reduced the cost and complexity to such a degree that it has become feasible for me to provide the first versions of these to anyone who wants one, at no charge.

/Steve.

Re: Primary General Discussion Area Analog-X64 12/6/12 4:09 PM
<lurker Mode off> :)

Hi Everyone,

Been following this project since last summer, and I'm glad it  has finally come to the stage where we can start building and testing.

I have 4 wiener dogs of my own, which contrary popular blief are not yappy and actually prefer to stay quiet and sneak attack anything at enters our yard.

Problem is the neighbors on the other side of my yard, bought a dog that just loves to taunt and start trouble with my dogs with its barking.

I've tried all kinds of solutions, various Anti Bark units which claim to make the high pitch sound to deter dogs from barking and I even bought
a automatic water squirting system... no go.

PS: long time Security Now listener, keep up the good work.

So I'd be interested in building one of these units, and planning on filming the unit in action when the time comes :)



Re: Primary General Discussion Area Steve Gibson 12/6/12 4:14 PM
WONDERFUL!!!

I'm working to get the design finalized and pages up on GRC with everything you'll need.

Thanks for your patience.  It won't be long now...

...and it has turned out WAY better than it would have been if I had driven ahead with last summer's approach.  I'm MUCH happier with the current approach!  :)

/Steve.
Re: [PSB] Re: Primary General Discussion Area Steve Plegge 12/6/12 5:10 PM
NEXT PROJECT SUGGESTION

Deer whistles that actually work.

Woof
--
On the Internet, no one knows you're a dog.  [Dogs Rule!]
Re: [PSB] Re: Primary General Discussion Area Mark Weiss 12/6/12 5:28 PM
The big money is in seals and sea lions, not that you can market it that way.  They sink docks and boats.  One boat owner new Newport Beach has had to have is boat raised 3 times because too many sea lions got on his boat and sank it.

But we don't want Steve get out of the Spinrite business. I'd pay for 6.x. upgrade if it would help.  It's starting to crash more often.
Re: Primary General Discussion Area trais...@gmail.com 12/6/12 10:20 PM
I am listening to GRC 381.  We have 2 dogs that will sometimes bark at 2am due to coyotes.  I would love to try out PDK when its ready, and will eventually have a Arduino ATtiny to turn it on when our dogs go off.  Maybe eventually set it up so I press a button in my room and it triggers one outside to scare off the coyotes.
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 12/7/12 8:50 AM
Anyone hvae pet deer to be vict-er volundeers  :)
Re: Primary General Discussion Area Brian 12/7/12 9:00 AM
So it looks like this project is basically using a Tweeter to stop a Woofer!

Sorry I just couldn't resist!

Re: [PSB] Re: Primary General Discussion Area Kindanyume . 12/7/12 9:10 AM
And the groaner bad joke of the day goes to....  :P
Re: [PSB] Re: Primary General Discussion Area Steve Plegge 12/7/12 9:54 AM
HEY!  I resemble that remark!

Woof

On 12/07/2012 11:00 AM, Brian wrote:
> So it looks like this project is basically using a *Tweeter *to stop a
> *Woofer*!
>
> Sorry I just couldn't resist!
>

Re: [PSB] Re: Primary General Discussion Area gni...@gmail.com 12/19/12 6:37 PM
I'm hoping to use it to stop tweeters.  Our local airport, where I have a
little old plane based, is plagued with starlings.  They love to nest in
any cranny they can find in airplanes, from the engine compartment
to tail surfaces.  Not to mention perching on antennas, stabilizers, and
props and pooping all over.  Having gone through one nesting season
with this plane, I know the areas they like to nest in it and I'd like to
modify this to have a sensor to trigger a brief blast to see if it can
persuade the little stinkers to move on.
unk...@googlegroups.com 12/19/12 6:39 PM <This message has been deleted.>
Re: Primary General Discussion Area Brian Hall 12/20/12 4:39 PM
LOL! That was hilarious. Thanks for sharing.
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 12/21/12 9:59 AM
OMG..   I almost fell out of my office chair laughing at that one!
Re: Primary General Discussion Area Steve Gibson 12/21/12 12:10 PM
Craig...

That's just TOO WONDERFUL!

I have ordered the 5th season (that was episode #9 of season #5) so that I can create a high-quality conversion.

I'm GOING to post it permanently on GRC's "The Quiet Canine" site!  :)

Thanks!!!

/Steve.
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 12/21/12 12:14 PM
Hope you ordered the 1080pBR then.. if not lmk and I'll see what I can
do here :)
Re: [PSB] Re: Primary General Discussion Area Steve Gibson 12/21/12 12:16 PM
Yes, of course I did!  :)

/Steve.
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 12/21/12 12:17 PM
hey just making sure!  :P

btw I'm editing a clip of said insane whippet barking to UL for
everyone to laugh at with a reasonable size file. ;)
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 12/21/12 12:36 PM
Well here ya go.. attempting to attach a vid of the "insane whippet"
(contrary to our usual problem this is virtually the only barking he
ever does.  Lets see if google groups handles it well)

WOOF!

 :)

(oh and no.. I am not working on a PDK for him.. unless I catch him
trying to steal food off the counter)
Re: Primary General Discussion Area birr...@gmail.com 12/26/12 12:30 AM
Dear Steve, dear Group Members!

My name is Robert, I'm from Romania and I would like to build this Portable Sound Blaster/Hush Puppy. I will be honest from the beginning and admit that I'm a noob in the world of electronics. This means that a schematic on itself is not enough for me to understand how an electronic device works and it's certainly not enough to build. So I need your help. Luckily I'm a quick learner and I would like to realize this build to give myself a push or in other words to reach the next level.

There are quite a few threads here and I just started to follow your project so if you allow me a few questions to make things clear and catch up that would be great. First off, I'd like to know if the intention is to build more versions of the device? The reason I'm asking this is that HERE I saw an already built, complicated Portable Sound Blaster with four speakers, ARM processor, parabolic reflectors, a large battery, etc. It looks very professional, but as I said it's complicated for a beginner to replicate the build. On the other hand in one of the threads here I saw a schematic about a very simple looking device using simple parts and only a 9 V battery as power source. So what's the situation?

Secondly, I'd like to know if one can already start experimenting even today? If I look at the "simple" version of the device, I think that I could start gathering the components and start experimenting on a breadboard. Do you think it is reasonable to do this and make adjustments along the way as new ideas emerge? Or is there a point you already have in mind to have the final schematic ready and it's worth waiting for that?

My third question is related to my situation. I live in an apartment house that has four floors and 20 apartments. I own a three bedroom flat on the second floor and there are many dog owners in this apartment house. On the ground floor there one particularly mean and loud dog that barks a lot when the owners are not at home and I'd like to do something about it. Would this device be "strong" enough to blast the sound through two or three concrete walls and make the dog stop barking? Or do I need to point it directly onto the dog and not have any walls or obstacles in between to have a result?

Thank you in advance for your help! Cheers, Robert

On Sunday, July 31, 2011 11:12:21 PM UTC+3, Steve Gibson wrote:
This is intended to be this group's primary general discussion area.

A high-end portable device is necessarily a sophisticated system incorporating a high-voltage/high-current rechargeable battery system, a microprocessor control and management system with audio input and output, user-interface input and output, and battery management subsystems, a high-power audio amplifier, and an enclosure designed to focus and aim the system's generated sound.

Since each of these are subsystems in their own right, we have broken these out into their own discussions.

But this topic is for general discussion.
Re: Primary General Discussion Area Steve Gibson 12/27/12 12:19 PM
Hello Robert...


My name is Robert, I'm from Romania and I would like to build this Portable Sound Blaster/Hush Puppy. I will be honest from the beginning and admit that I'm a noob in the world of electronics. This means that a schematic on itself is not enough for me to understand how an electronic device works and it's certainly not enough to build. So I need your help. Luckily I'm a quick learner and I would like to realize this build to give myself a push or in other words to reach the next level.

That sounds like a great plan, and this project is probably just about right for that.


There are quite a few threads here and I just started to follow your project so if you allow me a few questions to make things clear and catch up that would be great. First off, I'd like to know if the intention is to build more versions of the device?

I believe that there will eventually be TWO versions of the device:
  • The Two-Frequency, Firmware-Free, High-Power Harmonic Oscillator version which we have now at the increasingly stable version 2.2.1.  (Schematic PDF & PNG's attached).  This looks like the final design for a fixed 2-frequency sound generator.
  • A Variable-Frequency & Volume, Firmware-driven, High-Voltage Power Amplifier version which I am currently focused upon designing and fully specifying.  Since I generally focus intensely upon a topic and wrestle it to the ground, then move on... my hope is to obtain a working design along the original lines so that such a thing exists.
You should NOT wait for the second design (if I am even able to achieve it) since it will be more complex... and will definitely involve working with firmware, programming micro-controllers, etc.  It will be NO louder than the current design because it is not possible for anything to drive these tweeters any more loudly than the first design already does.  So #1 will be all you will ever need.


The reason I'm asking this is that HERE I saw an already built, complicated Portable Sound Blaster with four speakers, ARM processor, parabolic reflectors, a large battery, etc. It looks very professional, but as I said it's complicated for a beginner to replicate the build. On the other hand in one of the threads here I saw a schematic about a very simple looking device using simple parts and only a 9 V battery as power source. So what's the situation?

THAT, version 2.2.1 device IS the one you should build.


Secondly, I'd like to know if one can already start experimenting even today? If I look at the "simple" version of the device, I think that I could start gathering the components and start experimenting on a breadboard.

Right!

 
Do you think it is reasonable to do this and make adjustments along the way as new ideas emerge?

Yes.  Though I do think that we are "at rest" with the first design.

 
Or is there a point you already have in mind to have the final schematic ready and it's worth waiting for that?

Nope.  I might still tweak component values a bit in the first design, but it's very unlikely that much will change.

 
My third question is related to my situation. I live in an apartment house that has four floors and 20 apartments. I own a three bedroom flat on the second floor and there are many dog owners in this apartment house. On the ground floor there one particularly mean and loud dog that barks a lot when the owners are not at home and I'd like to do something about it. Would this device be "strong" enough to blast the sound through two or three concrete walls and make the dog stop barking? Or do I need to point it directly onto the dog and not have any walls or obstacles in between to have a result?

We don't know yet.  We know that other sonic devices have been found to be largely ineffective.  And we believe that this device will be the best possible attempt that we know how to make.  If you can hear the dog barking, then it will SURELY be able to hear this device.  But the device IS intended to be used in a direct line-of-sight mode. Being "able" to hear it, and having the sound be loud enough to serve as a deterrent are definitely different things.  For example... the dog might be "curious" about the sound and stop briefly... but then resume.  In the very few line-of-sight tests we have had, the dogs ran away as far and fast as they could move.


Thank you in advance for your help! Cheers, Robert

Glad to have you here and interested!

/Steve.
Re: Primary General Discussion Area Tom F 12/31/12 11:08 AM
Hi Steve-

I am so excited about this project that I've acquired parts for several previous versions. But as an electronics noob, I am having some difficulty following the discussion as it moves through revisions of theory and practice.
Yesterday, I saw reference to v2.2.2, Finally this morning I found the TQC-2.2.2.pdf but I still haven't found the discussion of what happened between 2.2.0 / 2.2.1 / 2.2.2, so I have no understanding of the second switch and what it does. In fact I don't know if these versions were due to minor but fatal bugs or performance tweaks.

I know that eventually finalized designs will get to GRC. In the meantime, could you (or someone that really understands it all) create a thread with the TQC-x.x.x.PDF and a brief, sentence of two, description of what the changes do and/or why they were made? 

Thank you for teaching me so very much. Happy new year!

-Tom
Re: Primary General Discussion Area Steve Gibson 12/31/12 11:44 AM
Hi Tom...

I believe that I have been careful to post everything about the recent design under THIS topic:

R&D Progress Log (See the END of this for the latest news.)

(I believe that you can click on that.)

I DID discuss everything very carefully blow-by-blow.  To follow the chronology, start at the top and read my postings down the thread.  You should find everything there!

/Steve.
Re: Primary General Discussion Area Steve Gibson 12/31/12 11:47 AM
Tom...

Here is the posting for the v2.2.0 announcement where I explain where everything came together:

Re: Primary General Discussion Area Braden Kear 1/1/13 1:46 PM
Steve, I built a couple of the v2.0.4 designs into hand-held units, and got one of them in front of a SPL meter yesterday. I have a couple other versions (v1 designs) on breadboard and I'll meter them later.

If the attached picture is missing, 124+ dB measured a few inches away from the tweeter. I saw as high as 126, but it settled down around 124.

-Braden
Re: Primary General Discussion Area Steve Gibson 1/1/13 2:06 PM
Braden,


Steve, I built a couple of the v2.0.4 designs into hand-held units, and got one of them in front of a SPL meter yesterday. I have a couple other versions (v1 designs) on breadboard and I'll meter them later.

If the attached picture is missing, 124+ dB measured a few inches away from the tweeter. I saw as high as 126, but it settled down around 124.

The photo made it.  Very cool.
Do you have any means for measuring the voltage across the tweeter?
What brand of tweeter?
What frequency?... do you know?
Do you know whether the sound level meter has good response all the way up there?
Do you know whether it is 'A' or 'C' weighted?

Thanks!

/Steve.
Re: Primary General Discussion Area Braden Kear 1/1/13 3:09 PM


On Tuesday, 1 January 2013 14:06:38 UTC-8, Steve Gibson wrote:
Braden,


The photo made it.  Very cool. 
Do you have any means for measuring the voltage across the tweeter?
 
Not peak to peak at the moment. My AC meter reads 26.5V (RMS I assume) which assuming a sine wave would be ~37.5V P-P (This doesn't seem correct. I'll try to get my hands on a scope)

What brand of tweeter?
 
Pyramid TW-105

What frequency?... do you know?

17.4kHz
 
Do you know whether the sound level meter has good response all the way up there?

The meter is only rated to 8kHz and I don't have data beyond that. (Extech 407730)
 
Do you know whether it is 'A' or 'C' weighted?

The meter has both modes, the measurement was taken in 'A' weighted mode, though I suppose the 'C' mode would probably be more appropriate.

Thanks!

/Steve.

-Braden 
Re: [PSB] Re: Primary General Discussion Area Kyle Smith 1/1/13 6:58 PM
Braden,

Very cool that you built a device!

Take a look at how SPL is typically measured from a point source of sound in air at 1 atm of ambient pressure (the pressure at sea level on a standard day.)  For many sources, 1 meter is the reference distance.  They use larger distances for jet engines and such, but I don't know of any data from a distance less than 1 meter, although you could theoretically measure from any distance, and then scale appropriately to 1 meter.


--
Kyle Smith (AG2F)

On Jan 1, 2013, at 6:09 PM, Braden Kear <brade...@gmail.com> wrote:

Braden,

I think that to get useful SPL ratings from a point source, that could be compared with other data, you need to measure the SPL at the more typical distance of 1 meter.  However, most SPL data are referencing a 0db pressure level measured at 1KHz.

--
Kyle Smith (AG2F)
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 1/1/13 8:23 PM
cool.. but what about at the standard 1w/1M?
Re: [PSB] Re: Primary General Discussion Area Braden Kear 1/1/13 9:11 PM
Thanks! I'll take some better standard tests and report back.

73

-Braden

Re: [PSB] Re: Primary General Discussion Area Kindanyume . 1/2/13 7:39 AM
No thank you..  you are the one doing the tests there :)
Re: Primary General Discussion Area birr...@gmail.com 1/2/13 10:23 AM
On Thursday, December 27, 2012 10:19:44 PM UTC+2, Steve Gibson wrote:
Hello Robert...


Thank you Steve for the detailed reply and for the encouragement!

I studied the components listed in the pdf document and I spent some time searching shops to buy them from. Below I'll list what I've found. As I wrote before, I'm from Romania and in my small town there aren't shops that carry components like this. I couldn't yet find local web-shops either so I'm afraid I'll have to order from eBay. This means that components will arrive in about 5-6 weeks so I need your input to be 100% sure that I got the right ones.

- 9 Volt battery: I have one already.
- Capacitor, 4.7uf, 25v, LINK.
- Capacitor, 4700pf, 50v, LINK.
- Capacitor, 0.22uf, 50v, LINK.
- Resistor, 22k, 1/8W, LINK.
- Push button: I think I can recover one from an old satellite receiver.
- Axial Power inductor, 1mH, LINK.
- High-Power MOSFET Driver: LINK.
- Piezo tweeter, LINK.

Thank you!
Re: Primary General Discussion Area wayn...@gmail.com 1/5/13 4:52 AM
That "- Axial Power inductor, 1mH, LINK." will not do. That one is all I could source in Australia and will not produce ANY volume at all.
Frequency output is correct but you need a better inductor than that one. I am awaiting one from digikey.com in the US and also one from Element14.com who have a local distributorship but that part they have to source from their USA supplier/branch. 1/2 Watt will not drive a 200W to 400W tweeter that well.
Re: Primary General Discussion Area Steve Gibson 1/5/13 5:07 AM

That "- Axial Power inductor, 1mH, LINK." will not do. That one is all I could source in Australia and will not produce ANY volume at all.
Frequency output is correct but you need a better inductor than that one. I am awaiting one from digikey.com in the US and also one from Element14.com who have a local distributorship but that part they have to source from their USA supplier/branch. 1/2 Watt will not drive a 200W to 400W tweeter that well.

You're absolutely right.  ALL of the inductors we've been using are POWER INDUCTORS which are quite different from RF Choke style light signal inductors.  They need to be able to handle on the order of 500mA and they will generally have resistances down in the 1 ohm range.

/Steve.
Re: Primary General Discussion Area birr...@gmail.com 1/6/13 4:14 AM
OK. I understand. Could you please recommend (and link) a suitable power inductor that can be bought off eBay?

Also, may I please get more info about he tweeter: wattage, frequency, etc.?

Thanks! Robert
FFT Library for Arduini Thomas Trostel 1/6/13 6:00 AM
I came across an interesting link to arduino based FFT systems while pursuing the "detection" aspect of the project.

http://neuroelec.com/2011/03/fft-library-for-arduino/

Teamed with the sonogram profile for a bark and Steve's excellent threshold wake up idea … its quite intriguing!  

Let me know what you think.

Tom T
Re: Primary General Discussion Area wayn...@gmail.com 1/6/13 6:56 AM
Try TDK-1mH-1000uH-1-1A-Power-Radial-inductors-5pcs-SL1215S-102KR51 but you'll have to buy 5. Better than the lots of 450 and 500 I last saw.

There is a separate thread for the Tweeter choices.

Wayne
Re: Primary General Discussion Area birr...@gmail.com 1/6/13 8:47 AM
On Sunday, January 6, 2013 4:56:58 PM UTC+2, wayn...@gmail.com wrote:
Try TDK-1mH-1000uH-1-1A-Power-Radial-inductors-5pcs-SL1215S-102KR51 but you'll have to buy 5. Better than the lots of 450 and 500 I last saw.

There is a separate thread for the Tweeter choices.

Wayne

Great! Thank you very much! I found the tweeter recommended by Steve in The Chosen Tweeter Family thread, but here's the link again just in case others are looking for it too.

So you're saying that all the other components I linked are OK? Even the 4.7 uF/25 V capacitors which are tantalum?

Robert
Re: Primary General Discussion Area Steve Gibson 1/6/13 9:04 AM
Yes...

Wayne's selection for the 1000uH (1mH) power inductor is perfect.


So you're saying that all the other components I linked are OK? Even the 4.7 uF/25 V capacitors which are tantalum?

I haven't checked through everything else as Wayne was kind enough to do.  But, yes, a tantalum 4.7uF capacitor will work beautifully.  One thing to watch for, however, and the reason I opened this posting, is that a tantalum capacitor will probably be POLAR (as opposed to non-polar).  It will be polarity sensitive. It may have "plus symbols" (+) marked on it, or one lead may be clearly longer than the other. And the polarity is crucial.  The longer lead will be the positive one if there's no other "+" marking.

/Steve.
Re: [PSB] Re: Primary General Discussion Area Kindanyume . 1/6/13 9:05 AM
excellent warning IMO

Even after studying EE yrs ago I had forgotten that lol
Re: FFT Library for Arduini Steve Gibson 1/6/13 9:25 AM
Thomas...
The "G" (value line) series MSP430's lack of hardware multiply is a problem with DSP applications.  But there ARE slightly more expensive MSP430's that DO have built-in memory-mapped multiplier.  You put a multiplicand and a multiplier into two words of "pseudo-memory" and two other words contains their product.

/Steve.
Re: [PSB] FFT Library for Arduino Thomas Trostel 1/7/13 2:48 AM
Point taken … 

Just another interesting challenge :-)

How about this puppy for a pre-amplifier for the microphone?  I like the shutdown feature for power saving!
I love the sound of 5nA!



Re: [PSB] FFT Library for Arduino Steve Gibson 1/7/13 6:24 AM

How about this puppy for a pre-amplifier for the microphone?  I like the shutdown feature for power saving!  I love the sound of 5nA!

Yes! That's a very nice looking little amp. Very nice.

/Steve. 
Re: [PSB] FFT Library for Arduino Thomas Trostel 1/10/13 5:24 PM
Just as a random search I came across the MAX038 chip too 
Re: [PSB] FFT Library for Arduino Thomas Trostel 1/10/13 5:54 PM
Or better yet … this one is pretty cool …

Re: [PSB] FFT Library for Arduino Steve Gibson 1/11/13 6:51 AM
BINGO!

Or better yet … this one is pretty cool …

It's not cheap, it's not in a DIP package.  But I love the voltage and digital interface.  That may be the one!

Nice find Thomas!

/Steve.
Re: [PSB] FFT Library for Arduino sigpoggy 1/11/13 1:27 PM
Here is a breakout board for $28 and free shipping.
Re: [PSB] FFT Library for Arduino Thomas Trostel 1/11/13 1:37 PM
I was going to use the adaptor from DigiKey (pn 309-1100-ND) … which is $5 … so yep it gets a little more pricey but not too bad!
Re: [PSB] FFT Library for Arduino Steve Gibson 1/11/13 1:55 PM
Wow... nice find!!

That solves the nightmare of a super-itty-bitty-smt package!

(But don't anyone buy one unless you just want to experiment on your own.  I think my original concept is shaping up.)

/Steve.
Re: [PSB] FFT Library for Arduino sigpoggy 1/11/13 1:58 PM
how do I view a .p7s file (on os x)?
Re: [PSB] FFT Library for Arduino Steve Gibson 1/11/13 2:15 PM
Thomas (and everyone)...

I was going to use the adaptor from DigiKey (pn 309-1100-ND) … which is $5 … so yep it gets a little more pricey but not too bad!

I LOVE the idea of that part, since it works at the voltage we want (3.3v) and uses a beautiful serial interface which we the MSP430's have.

My only trouble is that it doesn't give us any amplitude control... and I'd really like to have that.  It's not crucial, of course, but for the "UI" I'd like to be able to do some soft "dings" and "bongs" at a vastly reduced volume.

So I am still pursuing my whacky idea of feeding a uC-generated square wave into an extremely sharp digitally-controlled switched-capacitor filter having an ultra-sharp low-pass cuttoff.  And I BELIEVE that I have identified the chip that meets all of our requirements:

It's 3.3 volts, 8-pin DIP, very minimal external components... and anyone can have two for FREE as a "sample" from MAXIM:

It's the MAXIM   MAX7412CPA+

The way I would get volume control out of it would be to deliberately move the cutoff frequency a bit lower, thus causing our fundamental frequency to be attenuated by the filter's own filtering... which should give us a reduced-amplitude sine wave.

The ONLY trouble is that it's only rated up to 15khz maximum... though since there's nothing that actually limits that, I'm betting that it'll continue to work well if higher.  And, really, 15khz is fine anyway.

I'll have some of them tomorrow, and I am about to switch over to building the new "delta modulator" analog-to-pulse-width conversion idea to verify that we can do that as I suspect.  :)

If you, of anyone, wants to do some reading or background research, Wikipedia has some goodies (though rather more technical than my own pages will ultimately be:



/Steve.
Re: [PSB] FFT Library for Arduino sigpoggy 1/11/13 2:59 PM
This harkens back to the days when I had a PAiA synthesizer. 




Re: [PSB] FFT Library for Arduino Robert Foster 1/11/13 3:27 PM
Steve,

Perhaps you can remind some of us the reason for the concern that a square wave is not a sine wave.

I understand that the square wave introduces some ringing, etc and the sound is not so nice. But is the creature (dog, etc) going to care. And, it would seem that the harmonics will not be heard much anyway.

Perhaps we get a better power transfer to the tweeter if we use a nice sine wave.

Anyway, we wait with MSP 430s, tweeters, etc for the variable TrebleShooter. (I am having a great time learning Eagle with plans to make my own inexpensive circuit boards.)

Thanks again for the tremendous work.

Bob Foster
W4FXU

Sent from my iPad
Re: [PSB] FFT Library for Arduino Thomas Trostel 1/11/13 4:54 PM
Well … if we're just throwing components out there and you want volume control then you might like this one (DigiKey pn PGA2311P-ND)

Re: [PSB] FFT Library for Arduino Steve Gibson 1/11/13 6:32 PM
Hi Robert...


Perhaps you can remind some of us the reason for the concern that a square wave is not a sine wave.

I understand that the square wave introduces some ringing, etc and the sound is not so nice. But is the creature (dog, etc) going to care. And, it would seem that the harmonics will not be heard much anyway.

Perhaps we get a better power transfer to the tweeter if we use a nice sine wave.

Yes, that's it exactly.

The existing "Adjustable Treble Shooter" project does a very nice job of driving the tweeter within the limitations of an "inductor kicked" square wave.

But there's truly a mechanical system out at the end of the wires, and it is physically incapable of responding instantly to a square edge.  To help with that, I deliberately added the series inductor which, being in inductor, resists any change in current through it by either dumping or retrieving any attempted change to or from the potential energy stored in the magnetic field of its core.  So that "takes the edge off".

But while this makes it somewhat better, it's necessary to use a small inductor so that its natural resonance with the tweeter's capacitance will be far outside of our operating region... otherwise we risk hitting resonance and destroying the tweeter.  So the v0.5 schematics are using a small inductor which resonates out around 45kHz with a typical tweeter.  And THAT, in turn, means that we are still driving the tweeter erratically.

And... the reason THAT matters, is that...

A.) I want to explore the limits of what we can do, and that requites that the waveform we drive the tweeter with a perfect sinusoidal shape. A sinusoid which is unique in that it, by definition, has the LOWEST MAXIMUM ACCELERATION POSSIBLE for the resulting amplitude.  In other words... to generate the maximum possible excursion of the tweeter's diaphragm, which we want in order to make the loudest possible sound... the only way to simultaneously minimize the acceleration we must apply to the tweeter -- which preserves it and allows it to be more efficient, and to turn the least amount of input energy into waste heat -- we need to give it a sine wave.

B.) An unanswered question, is whether another completely different physical architecture for the system's "speaker" transducer might be feasible. I want to determine what happens if we simply mount a piezo "bender", using flexible silicon RTV adhesive, to the end of a simple tube...

If it is operated at the tube's resonance, there's every reason to believe that it might be the loudest, most powerful and directional sound beam emitter possible.  But that can ONLY be done if we are oscillating the closed "end cap" of the tube under the influence of a beautiful sine wave... so that clean and pure standing waves will be established when the outbound wavefronts are reflected back into the tube to reinforce and amplify each other within the tube.

So... I'm just taking this one step at a time.  :)

/Steve.
Re: [PSB] FFT Library for Arduino Kindanyume . 1/12/13 7:14 AM

B.) An unanswered question, is whether another completely different physical architecture for the system's "speaker" transducer might be feasible. I want to determine what happens if we simply mount a piezo "bender", using flexible silicon RTV adhesive, to the end of a simple tube...

If it is operated at the tube's resonance, there's every reason to believe that it might be the loudest, most powerful and directional sound beam emitter possible.  But that can ONLY be done if we are oscillating the closed "end cap" of the tube under the influence of a beautiful sine wave... so that clean and pure standing waves will be established when the outbound wavefronts are reflected back into the tube to reinforce and amplify each other within the tube.

So... I'm just taking this one step at a time.  :)

/Steve.


Now that is very interesting.. and way out of my area w/any "speaker"... I'd have never thought of that in a million years.. but now you have mentioned it..  very exciting to even contemplate such a radical jump. :)

Re: [PSB] FFT Library for Arduino David Doyle 1/17/13 7:13 PM

Hi Folks,

Sorry to be off topic but my 13 year old son has become very interested when he saw me working on the TQC board.  I was wondering if any of you could recommend some good learning kits that would help teach him (and remind his old dad) on the basics of electronics.

Thanks in advance.
Re: [PSB] FFT Library for Arduino Brian Hall 1/17/13 7:22 PM
I had the same questions. If you search for "snap circuits" on Amazon, you'll find some awesome kits for electronics beginners (example: http://www.amazon.com/Elenco-SC-300-Snap-Circuits/dp/B0000683A4/ref=sr_1_6?ie=UTF8&qid=1358479060&sr=8-6&keywords=snap+circuits+elenco). 

I'd love to buy one of these kits for my kids and I to learn. Each electronic component snaps together, and has the schematic symbol for the particular piece. It comes with instructions for how to build a bunch of different things. There are different versions of the kits with different numbers of pieces, etc.

Brian Hall
Re: [PSB] FFT Library for Arduino David Doyle 1/17/13 7:39 PM
Thanks.  That looks something like the one I had back in the 1970s :)
Re: [PSB] FFT Library for Arduino garywhit...@gmail.com 1/17/13 8:54 PM
Here are some resources that I have found helpful. 

I started the kids out with a snap-circuits kit a few years ago.  I had as much fun as they did with it.  We wanted some more info on beginning electronics and found Super Awesome Sylvia on the cover of a Make magazine.  What an inspiration!  http://sylviashow.com/episodes

Check out this kit from Sparkle labs: http://sparklelabs.com/index.php.  They have some youtube videos on beginning electronics too: http://www.youtube.com/watch?v=GcbZ3UElhsQ

Last year I bought a Drawdio kit from http://www.ladyada.net/make/drawdio/ and my girls (8 and 11) and I had a great time building it and learning together.  last Christmas I bought them a Simon game from Sparkfun: https://www.sparkfun.com/products/10547 and a tv-b-gone from http://www.ladyada.net/make/tvbgone/.  I was so proud they each built a kit completely on their own (with a little guidance from me) and they worked the first time.  The tv-b-gone is GREAT FUN when you go out to eat and are bothered by inappropriate content blaring from the TV in front of your kids (or when walking the dog at night and people have their TVs facing the sidewalk (bwaaa haa haa!)).  note that my dog doesn't need a Trebleshooter but other neighborhood dogs do.  :-/

Ask the Google about bristlebots.  They look simple and fun.  I have the parts on the bench but we have not yet made any.

Have fun and glad to hear you are passing on the curiosity/learning gene to your son!

Gary
unk...@googlegroups.com 1/24/13 9:30 AM <This message has been deleted.>
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