V2.2.2 Construction Q&A Thread

[Liquidretro]

I thought it might be a good idea (and make things more clear) to create a new thread dedicated to V2.2.2 Construction.  This will allow us to keep discussions here separate from the microcontroller version and answer peoples questions as they receive parts and build.  

[Liquidretro]

My question is on the design, which Switch is the main On/Off switch and which is the frequency drop switch?  I have 2 different types of switches and I want to use my larger one as the On Off.  I am guessing that S1 is the Main switch and S2 is the Frequency drop based on the diagram but was not 100% sure.  

Thanks

[Steve Gibson]

I agree Liquidretro.

I've given this (your) topic "Display At Top" status so that it'll be MRP-sorted (Most Recently Posted) among all of the "Display At Top" topics.

/Steve.

[Steve Gibson]

Yes!  Exactly right.

My question is on the design, which Switch is the main On/Off switch and which is the frequency drop switch?  I have 2 different types of switches and I want to use my larger one as the On Off.  I am guessing that S1 is the Main switch and S2 is the Frequency drop based on the diagram but was not 100% sure.

/Steve.

[Steve Cirelli]

I haven't build a circuit since high school so I'm really rusty at this. 

I put v2.2.2 together. Pressing S1 seems to produce a lower freq noise, and when I press S1 and S2 together I get the really loud annoying sound (higher freq?). So what do you mean by freq drop? Could I have wired something together wrong? 

[Steve Gibson]

Steve...

That all means that you haven't lost your touch. It "sounds" like it's working.

Try asking a teenager about S1 only! It's very likely that you can't hear it.

S1+S2 is designed to help us to appreciate just how acoustic energy this thing is putting out that WE cannot hear.

/Steve. (Wandering around loose somewhere)

---

From: Steve Cirelli <scir...@gmail.com>

Sender: portable-so...@googlegroups.com

Date: Fri, 11 Jan 2013 08:19:08 -0800 (PST)

To: <portable-so...@googlegroups.com>

ReplyTo: portable-so...@googlegroups.com

Subject: [PSB] Re: V2.2.2 Construction Q&A Thread

[David Doyle]

Hi Folks,

I'm a geologist with some understanding of electronics (more than the average Joe but no where Steve).   I've ordered the parts for 2.1 and got Goldwood GT-1005 Wide Dispersion Piezo Tweeter http://www.parts-express.com/pe/showdetl.cfm?partnumber=270-011 the tweeter.

I didn't have any luck last night.  I was wonder if I should:

1 - Work with 2.2.2 instead of 2.1

2- Use a different tweeter

3 - 1 and 2

4 - wait until the smart guys get it down pat and do it then :)

Thanks for your input.

David

[coo...@gmail.com]

You might check the pin locations in the schematic against the chip schematic.......The pin locations are different....You need to use the chip schematic.........f

[Steve Gibson]

You might check the pin locations in the schematic against the chip schematic.......The pin locations are different....You need to use the chip schematic.........

Whoa!  At first I thought that perhaps I had somehow messed up the schematic!  But then I realized that there was (maybe) some confusion about the schematic being a PICTORIAL of the CHIP (which schematics never are).  But, that said, I can also see that IF I were to use a pictorial image of the 8-pin DIP chip, it might make for a much clearer construction for many people.

Thanks!

/Steve.

[Myron Reiss]

I learned this last night, and today, when I should have been working, I came up with a circuit board layout or plan for V1.1 it looks like this

[Liquidretro]

This looks more like a Diagram for Version 2.2.2 than V1.1.  Can you double check this?  

[Steve Gibson]

 

This looks more like a Diagram for Version 2.2.2 than V1.1.  Can you double check this?

He's got it right.  v2.2.2 has no microprocessor.  It uses the 8-pin inverter/driver chip only.  :)

/Steve.

[Liquidretro]

Ah I should have caught that.  

[Liquidretro]

I accidently ruined my C1 capacitor.(A leed came out while unsoldering it)  I was able to find an identical valued one locally, however it's an electrolytic capacitor instead of a ceramic capacitor.  Electrolytic capacitors are polarized, so I was first wondering will this be ok in the circuit?  I know the ceramics are a closer tolerances and better for what we are doing here, but I am assuming this electrolytic one will work?  If it will work, which direction should it go? Or should I just bite the bullet and order another from Digikey and pay a significant amount to ship a $0.38 part.  

[Kindanyume]

Sorry.. but if you can't find a ceramic of equiv value locally...
where the hell are u living?? O.o;;

[David Doyle]

Thanks but currently I'm still working on 2.1 http://www.GRC.com/tqc/TQC_v2.1_Schematic.pdf which uses the MOSFET N-CH 60V 18A 43MOHM IPAK  http://www.onsemi.com/pub_link/Collateral/NTD5867NL-D.PDF

I went with 2.1 being that was the simplest I could find and wanted something would be easy being I don't do a lot of this kind of work :)

I didn't know if there was something I was missing in the diagram or if my tweeter was bad or if I needed to go with 2.2.2.

Thanks again.

[Liquidretro]

 David I saw your post above, and am not sure how to help you.  Someone else responded with some help it looks like.  General advice is to double check your circuit and component placement and connection points.  If you have a multimetere you can check the circuit in various places like speaker outputs etc.  

[David Doyle]

Thanks

[Liquidretro]

Capital city in the midwest.  The local electronics shop only had the electrolytic type.  I have not tried Radioshack but figure they won't have anything since they never do, but I suppose it's worth a drive.

[Steve Gibson]

 

I accidently ruined my C1 capacitor.(A leed came out while unsoldering it)  I was able to find an identical valued one locally, however it's an electrolytic capacitor instead of a ceramic capacitor.  Electrolytic capacitors are polarized, so I was first wondering will this be ok in the circuit?  I know the ceramics are a closer tolerances and better for what we are doing here, but I am assuming this electrolytic one will work?  If it will work, which direction should it go? Or should I just bite the bullet and order another from Digikey and pay a significant amount to ship a $0.38 part.

You probably don't really need it at all.  I'd say give it a shot, using both buttons to verify the REALLY LOUD AND ANNOYING TONE.

It's instinct for me to obey best design practices... but in this application I really doubt that C1 is needed at all.

In fact... I may eliminate it from the design once I have verified that, now that you have pointed it out.

Normally, a "local capacitor" is placed electrically close to any chip that might experience the need for short bursts of high-current... something that ceramic capacitors excel at.  But that's just not needed at all in this design.  The MOSFET driver chip is not driving any MOSFET.  It's just yanking the upper-end of L1 up and down.  And that's an ENTIRELY different task than if it were trying to charge and discharge a MOSFET's gate capacitance quickly.

So... the more I think about it... get rid of it!!  :)

/Steve.

[Kindanyume]

eeek... so middle of nowhere?

No offense btw... but electrolytics' are consistently crap for
reliability sadly. :(

And yes.. technically in theory afaik it should work.. but wow.. that
is insanely rare to not have access to ceramics esp in this day and
age (and I'm IN Canada btw.. much smaller market etc etc)

[Steve Gibson]

Thanks but currently I'm still working on 2.1 http://www.GRC.com/tqc/TQC_v2.1_Schematic.pdf which uses the MOSFET N-CH 60V 18A 43MOHM IPAK  http://www.onsemi.com/pub_link/Collateral/NTD5867NL-D.PDF

I went with 2.1 being that was the simplest I could find and wanted something would be easy being I don't do a lot of this kind of work :)

I didn't know if there was something I was missing in the diagram or if my tweeter was bad or if I needed to go with 2.2.2.

Wow.  How far we've come.  That schematic is only three weeks old... yet it seems like a lifetime ago that we were using that dual-inductor design!  Wow.

/Steve.

[Liquidretro]

Thanks Steve,  I will build it without tonight/tomorrow and update everyone on how it works.  

[Liquidretro]

Hey now, It's not that bad.  Major public university in town, just not a lot of hobbiest electronics shops that I know of. 

[Brian Hall]

I was skeptical as well, but went into a Radio Shack last week to get some electronics components for another project, and was pleasantly surprised at their selection. I guess it might vary based on store location, though. My Radio Shack had a big chest of drawers with all of the components one could ever need all organized into little dividers. It was a great experience. But, they do charge more than online suppliers, and of course their staff sometimes don't have any idea what you're asking for--and may try to sell you overpriced batteries, etc. :-)

Brian Hall

[Kindanyume]

lol..

Sorry but why do you think they are commonly called "Radio Shit"?

[grebulon grebulonovich]

Hello

I've been reading this group for some time, and now I'm going to build a tqc of my own.

I'd like to experiment with a range of frequencies, say from 12KHz to 20KHz.

The question is, what range of inductors should I buy? Or should I play with the values of C2?

--grebulon

[Steve Gibson]

Grebulon,

Pushing the "low frequency button" drops the non-C2 16khz tone down to about half that, or 8khz.  And power remains very high.

So adding various values for the role of C2 works well.

If you want to experiment with higher frequencies than 16khz, you could get one additional lower-value inductor for experimenting.

820uH is another standard value which would put you right up around 20khz with the tweeter's inherent capacitive reactance.

I would choose this Digikey 820uH inductor: AIUR-08-821K-ND  ($0.63 in singles)

Next... since paralleled capacitors SUM their capacitances, you can simply get a few selected capacitors and obtain many frequencies by combining them:

0.015uf   445-8626-ND

0.022      445-8627-ND

0.033      445-8629-ND

0.047      445-8630-ND

0.100      445-8360-ND

(Note, these are all 100v rated, since that's important.)

/Steve.

[Liquidretro]

I was incorrect in my post yesterday.  The capacitor that I ruined was not C1 but instead C3.  I figure C3 is not necessary so i tied the tweeter to the switch.  It appears I may have a faulty switch which I will replace today but I am assuming I should still get a tone.  I did build the circuit without C1 (that I have) to test it and obviously things are not working.  Wondering if I should go ahead and put it in, and repair the switch or just do the switch.  When I hook it up now, my battery starts to get warm, so there is something not right.  

[silver...@gmail.com]

Steve, thank you so much for all your work and for everyone's contributions on this project. I just finished breadboarding v 2.2.2 and it WORKED! My dog perked right up and I could barely hear the tone too.

Being a noob to electronics I'm wondering, would putting the various C2's in parallel need to be set up as separate circuits and then selected through a selector switch? Or is there a way to add more capacitors in parallel using a selector switch?

[silver...@gmail.com]

Dooh! A dip switch or toggle switches would be able to add in the parallel capacitors.

[Steve Gibson]

I was incorrect in my post yesterday.  The capacitor that I ruined was not C1 but instead C3.  I figure C3 is not necessary so i tied the tweeter to the switch.  It appears I may have a faulty switch which I will replace today but I am assuming I should still get a tone.

Whoops!!  No!!  If you don't use C3 and just tie the switch directly across the tweeter, you'll be SHORT CIRCUITING the tweeter and putting a HUGE strain on the rest of the system.  If you don't have C3, YOU CAN NOT USE the second Pushbutton.

And you cannot replace C3 with anything else... since it needs to be a high-voltage non-polar capacitor.  That's crucial.

 

I did build the circuit without C1 (that I have) to test it and obviously things are not working.  Wondering if I should go ahead and put it in, and repair the switch or just do the switch.  When I hook it up now, my battery starts to get warm, so there is something not right.

It's unclear (to me) what you meant by those sentences. Your references weren't specifying what you were speaking of.

But your battery should NOT be getting warm unless you have shorted the tweeter.  And also... CAREFULLY check the temperature of the 8-pin DIP chip.

/Steve.

[Steve Gibson]

Dooh! A dip switch or toggle switches would be able to add in the parallel capacitors.

Exactly right!  :)

/Steve. 

[Dabble]

Hey guys I need some help.


I purchased all the parts from DigiKey that Steve listed in the 2.2.2 schematic, also four kinds of cheap tweeters that steve showed in the tweeter family post.

Been having trouble getting the 2.2.2 schematic to work on a breadboard, I am a beginner when it comes to electronics and schematics and putting them on a breadboard so I have some pictures of my setup for you guys to look at, I can't figure out
what I'm doing wrong.

When I push S1 I hear a very low audible kind of click sound like the tweeter got a little power for a split second but that's about it, I hear nothing when I press S2 with with S1.

I must be shorting something, I bought 4 sets of parts just in case something like this happens so I can swap parts that I might brake, so swapped them once but received the same results.

Are Piezo Tweeters polarity sensitive for negative and positive connections, I tried hooking them up -+ +- -- ++ nothing changed.

I wanted to make sure I could get it right on a bread board before soldering it all together, could it be that the alligator clips that go to the tweeter are to long or not good conductors?


Thanks.

[sigpoggy]

I have breadboarded the circuit and have been playing around with it. I am using my iPhone as a db meter. At first I put it a meter from the speaker to measure and got 103db. But as I played with things, such as the battery voltage, I noticed I could go down to 3V and it still read 103 db. So I got a mic setup and monitored it with my oscope and saw the change I should have seen on the db meter. Even though the meter scale went to 110, the phone could only handle 103 before it pegged. So I moved the phone out about 25 feet and got a measurement of 95db at 8.5K and 86db at 17K . By my calculation, that means the levels at one meter would be it would be about 17db louder.

9V supply single speaker:

8.5K is 112db

17K is 103db

It occurred to me a cheap way to up the amplitude is to connect the second tweeter so...

I hooked the second tweeter up in parallel and pegged the meter. It also shifted the freq to 12K. Will have to wait till tomorrow to find longer distance to do the measurement.

In the mean time I dropped the battery voltage to 3V and got a measure of 83-86 db @17K for one speaker and 93 db @12K for two speakers. Adjusting for the distance:

3V supply single speaker

17K is 101db

3V supply two speakers

12K is 110db

Thus it seems at the lower voltage we see a 9db increase with two speakers. This is not an accurate measurement, but might be useful in judging things.

Interesting that the change in supply doesn't have that much effect on db level for the single speaker. A factor of 3 is quickly swamped in the db scale.

Will post results of next test tomorrow.

 

[sigpoggy]

Looks to me like you have the battery shorted out through S1 - Battery + to green wire, to S1, to yellow, to brown, to brown, to yellow, to - Battery.

[sigpoggy]

By the way, to makes things easier if you use the holes along the edge marked + (at the top) and - (at the bottom) for +9V and ground respectively. All the holes on one edge are connected.

On Sunday, January 13, 2013 8:04:40 PM UTC-8, Dabble wrote:

[Damien Good]

On Sunday, January 13, 2013 11:18:02 PM UTC-8, sigpoggy wrote:

I have breadboarded the circuit and have been playing around with it. I am using my iPhone as a db meter. At first I put it a meter from the speaker to measure and got 103db. But as I played with things, such as the battery voltage, I noticed I could go down to 3V and it still read 103 db. So I got a mic setup and monitored it with my oscope and saw the change I should have seen on the db meter. Even though the meter scale went to 110, the phone could only handle 103 before it pegged. So I moved the phone out about 25 feet and got a measurement of 95db at 8.5K and 86db at 17K . By my calculation, that means the levels at one meter would be it would be about 17db louder.

9V supply single speaker:

8.5K is 112db

17K is 103db

It occurred to me a cheap way to up the amplitude is to connect the second tweeter so...

I hooked the second tweeter up in parallel and pegged the meter. It also shifted the freq to 12K. Will have to wait till tomorrow to find longer distance to do the measurement.

The frequency shift is because the Tweeter also has capacitance.  By hooking up a second tweeter in parallel, is just like hooking up capacitors in parallel.  If you need 16-17K from the two tweeters, you have to also adjust the inductor to compensate for the added capacitance.

 

[sigpoggy]

Made my measurements at 12 meters then adjusted for distance resulting in:

8.6V supply two speakers

both 12K and 7K are about 120db at 1 meter (99db at 12 meters)

(the 8.6v is due to having to use a battery that is a little run down in stead of my lab PS.)

Note that 120 db is the threshold level at which immediate hearing loss begins. If someone builds this device, uses two speakers and blasts someone from a meter away, they could instantly cause permanent hearing loss.

This is a preliminary analysis and not necessarily accurate. My meter is not calibrated and I'm not an expert in hearing science. But I think this information should be assumed to be possibly true and the margin of error means the danger could be higher.

An idea: build the device with two tweeters with a toggle switch to kick in the second tweeter for longer range.

On Sunday, January 13, 2013 11:18:02 PM UTC-8, sigpoggy wrote:

[Steve Gibson]

Dabble...

Sigpoggy's right.  You just need to move the left end of the YELLOW jumper down two rows, to pin 8 of the chip:

In the image above (and full-size attached) I show the short circuit path in CYAN and the change needed in BLUE (over between S1 and U1).

/Steve.

[Steve Gibson]

Sigpoggy...

9V supply single speaker:

8.5K is 112db

17K is 103db

It occurred to me a cheap way to up the amplitude is to connect the second tweeter so...  I hooked the second tweeter up in parallel and pegged the meter. It also shifted the freq to 12K. Will have to wait till tomorrow to find longer distance to do the measurement.

How cool!  I also had the same thought about using two of the Pyle Surface Mount Tweeters when we were talking yesterday about a bark-sensing dog collar:  I would mount the electronics package and battery to go under the dog's throat with the collar clasp in the back of the neck-head... and the mount the two little Pyle surface mount tweeters on either side, 90 degrees around, so nearer to each ear.

It's difficult to imagine that any dog could bark many times if a short sharp blast from a PAIR of those was the retort!

 

In the mean time I dropped the battery voltage to 3V...

Clever to drop the voltage to bring your one/two tweeter testing back into the range of your measuring.  :)

 

...and got a measure of 83-86 db @17K for one speaker and 93 db @12K for two speakers. Adjusting for the distance:

3V supply single speaker

17K is 101db

3V supply two speakers

12K is 110db

Thus it seems at the lower voltage we see a 9db increase with two speakers. This is not an accurate measurement, but might be useful in judging things.

Very nice!

 

Interesting that the change in supply doesn't have that much effect on db level for the single speaker. A factor of 3 is quickly swamped in the db scale.

I've got to say... it's an INCREDIBLE little circuit.  I'm so pleased with it and proud of it.

I am also pleasantly surprised that the TC4421A inverter runs down at 3v. It's rated only down to 4.5v.

I have also been thinking along the same lines -- of a 3 volt system (since that's microcontroller friendly) -- I have some classic CMOS Hex Inverters on the way... since they are less expensive, can be parallel to achieve higher total current, and draw no power when not switching.

Will post results of next test tomorrow.

Neat!

/Steve.

[David Doyle]

Hi Jim,

Great post. I checked with one of the health and safety guys that I
work with and he said you are correct about 120 db. He also said they
use the rule of 6 as a rule of thumb for noise reduction over
distance. If you double the distance the sound will reduce by 6 db
which checks with what you measured.
1m = 120 db
2m = 114 db
4m = 108 db
8m = 102 db
16 = 96 db

or you can do it online at
http://www.numericalexample.com/index.php?view=article&id=18

It also depends on humidity, temp, and feqz but it is a good rule of thumb.

Here is web page that takes the others into consideration.
http://www.sengpielaudio.com/calculator-air.htm

Take Care
David

[Dabble]

Hey Guys,


Thank you very much Sigpoggy and Steve, that was it!  Steve thank you for posting the retouched image, made it real easy for me to see what I did wrong.

I tested it in my bedroom, tapped S1 and I knew it was fixed (Ears Rang), then I started pushing  S1 and S2 a few times and the rest of the FAMILY in the house REALLY knew it was fixed... ;)

Will try to put it on some Perfboard board next, hope I don't have any problems there.


Thanks again.

[Steve Gibson]

Will try to put it on some Perfboard board next, hope I don't have any problems there.

The other day I was putting together a new uC-based breadboard.  And I recalled an old trick from the early days:

Print out the schematic -- perhaps double or triple size.  And AS you make each connection, with a highlighter draw over the connection lines on the schematic.  That way you always have a accurate running map of what you HAVE connected, and what you HAVEN'T yet.  It's really VERY handy... especially as things become more complex.

/Steve.

[Kindanyume]

indeed.. that is the same trick as i was taught
wayyyyyyyyyyyyyyyyyyyyyyyyyyyy back when and then taught my class
mates at DeVry. years after that.

Though initially I had to use the main office to get access to the
photocopier and printers of the day were useless for this of course..
so I had to be "creative" with blowing it up.

[Dabble]

Great tip Steve thank you very much.

[hausm...@gmail.com]

I have all the components ready to go, but I am new to breadboarding. Can someone post theirs on a breadboard so I can see the finished layout?  I tried twice and failed. I am having trouble transposing the schematic to the breadboard.  I don't have any experience, but I am interested and trying. 

thanks,

Dan

[Myron Reiss]

I did v1.1.1 and it was my first time too. 
tips:  You can cut it with a tin snips.
I made a bunch of sketches turning the parts around so I don't have wires all over the place.
The layout don't have the terminals in the right place (thats just how they do them).

That's what I figured out so far.
Myron

[Myron Reiss]

picture

[Brian Hall]

Hey Dan,

I found the following videos pretty helpful when getting started. I never used a breadboard, just a perforated copper-padded proto board from Veroboard (which I ordered through Amazon). This was my first experience assembling an electronics project from a schematic.

http://www.youtube.com/watch?v=9cps7Q_IrX0

http://www.youtube.com/watch?v=vJUX9cvyYjU

I printed out the v.2.2.2 schematic and used it as a "table mat" upon which I did the assembly of the components. I've learned that assembling a circuit from a schematic is "both an art and a science". I constantly referred back to the schematic to determine what components connected together. I would trace the path from beginning to end, making sure that the right components were soldered together. You don't necessarily have to follow the exact layout of the schematic--it is purely informational and just tells you how things connect. You can move components around on the physical board itself when you actually assemble the parts. TrebleShooter v.2.2.2 is simple enough that you can figure out how to put it together with minimal experience.

Trust me, I was nervous before I began, too. But, keep at it--you'll figure it out, and you'll be satisfied when you do!

Brian Hall

On Fri, Jan 18, 2013 at 3:11 PM, <hausm...@gmail.com> wrote:

[Steve Gibson]

Dan...

The trickiest part, I think, is getting the PIN NUMBERS correct.  The schematic DOES NOT SHOW the pins where they are on the chip!  I am going to change that in the future to make things clearer, but I haven't yet.  Here's the way an 8-pin chip's pins are ACTUALLY numbered:

/Steve.

[David Doyle]

Hi Dan,

Look under
V2.2.2 Construction Q&A Thread
Look for the post by Dabble 1/13 that has his Breadboard
and for the post from Steve G on Steve Gibson with the correction by Steve.

Take Care
David

On Fri, Jan 18, 2013 at 3:11 PM, <hausm...@gmail.com> wrote:

[hausm...@gmail.com]

Thanks Steve.  I stepped away for a while and when I came back I got it to work.   Unfortunately, I broke one of my switches.   In the short term I replaced the s1 with the white jumper.  If all goes well with the perf board and finding better switches, I should have some finished product photos tomorrow.

[Steve Gibson]

Cool!!!

Thanks Steve.  I stepped away for a while and when I came back I got it to work.   Unfortunately, I broke one of my switches.   In the short term I replaced the s1 with the white jumper.  If all goes well with the perf board and finding better switches, I should have some finished product photos tomorrow.

/Steve.

[David Doyle]

OK guys where did is mess up???

I just have jumper in instead of switches for the test run and hook up the battery to turn it on.

U1 gets hot when the battery is hooked up.

Thanks in advance.

[Steve Gibson]

David...

It seems right to me.  Is the chip inserted with the correct orientation... with the "notch" on the top located between pins 1 and 8?

/Steve.

 

[David Doyle]

Hi Steve,

Yes the notch and dot are at the top.  Does U1 get hot during normal operations??

[Steve Gibson]

No.  It never should become warm at all.

If it had been connected wrongly in the past, it may have died then?... and now, even when correctly hooked up, it's unhappy?

--

/Steve.

[David Doyle]

Popped it out and put in another U1 (got 3 of everything to be safe).  Still no sound.  Could the tweeter be dead??  I've never heard sound from it.

Photo showing the notch is attached.

[Steve Gibson]

David...

Popped it out and put in another U1 (got 3 of everything to be safe).

Good man.

Still no sound.  Could the tweeter be dead??  I've never heard sound from it.

You CAN connect it directly to the 9v battery without any harm to anything... as follows:

Every time you reverse the battery's polarity, you should be rewarded with a clear and distinct "tick" sound as the tweeter's diaphragm jumps into an "inwardly" or "outwardly" oriented position.  But since that action also charge's the tweeter's capacitance, doing it again with the same polarity won't work.  You could short the tweeter to discharge it.  But it's easier just to reverse the battery connection polarity to obtain another "tick" from the tweeter.  And you can do it many times.

That protocol is a simple and great way to check a piezoelectric tweeter.

/Steve.

[Steve Gibson]

David!

If the tweeter WERE bad and "short circuited" that WOULD cause the chip to overheat.

Do this: simply disconnect the tweeter.

Does the chip still get warm??

Background:

If the tweeter were a short-circuit internally, the input to the inverter would be help LOW. That would force its outputs HIGH... Which would mean that it was trying to pull its end of the very low resistance inductor up to 9 volts -- with the other end of the inductor being held low by the shorted tweeter... AND THE CHIP WOULD GET HOT!

/Steve. (Wandering around loose somewhere)

---

From: David Doyle <kydavi...@gmail.com>

Sender: portable-so...@googlegroups.com

Date: Fri, 18 Jan 2013 21:29:50 -0800 (PST)

To: <portable-so...@googlegroups.com>

ReplyTo: portable-so...@googlegroups.com

Cc: <hausm...@gmail.com>; <hausm...@gmail.com>

Subject: [PSB] Re: V2.2.2 Construction Q&A Thread

[Steve Gibson]

Builders and Future Builders...

This little slice of heaven will save your sanity. It's only $3.50 from Digikey (700-00012-ND) and it's ALL anyone would need to prototype build the v2.2.2 TrebleShooter before committing it to a permanent soldered build.

All of the five-column connector holes are tied together, and the hole spacing is 0.10" -- which is the same as the 8-pin DIP inverter chip.  So you straddle the chip across the center gap... then simply plug solid hookup wires and component leads into the remaining four holes to interconnect everything in a "solderless" fashion.

You can spend more if you wish to get more bells and whistles;;;

http://www.digikey.com/product-search/en/prototyping-products/solderless-breadboards/2359510

And you can also get a kit with a larger (not needed for v2.2.2 but WILL BE NEEDED for the forthcoming uC-based design) breadboard: 1050-1012-ND

Or just a sweet little 140-piece $9 kit of ready-to-go jumper wires: 438-1049-ND

And you might want to poke around here for other goodies:

http://www.digikey.com/product-search/en/prototyping-products

/Steve.

[sigpoggy]

One thing I notice is that you are not aware of how the two outside hole rows work. The strips on the outside with only two rows of holes are meant to be used for power and ground. As such, the holes in each row are all connected. The holes in the center of the board connect horizontally while the holes in the outside strips connect vertically. So for example your C3 is short circuited.

[Steve Gibson]

Jim...

One thing I notice is that you are not aware of how the two outside hole rows work. The strips on the outside with only two rows of holes are meant to be used for power and ground. As such, the holes in each row are all connected. The holes in the center of the board connect horizontally while the holes in the outside strips connect vertically. So for example your C3 is short circuited.

That's ALMOST correct.  But for the sake of completeness, I would add that:

The horizontal "bus" connections are all connected... EXCEPT that on SOME breadboards the horizontal busses are BROKEN at the mid-point of the bus. This is usually apparent because the "sets of five" holes will have a larger separation at the center point of the board.  So... for such boards, you'll need a single jumper to span across that larger gap, thus uniting the left and right halves.

(This seems to be more true for older breadboard than newer ones.)

/Steve.

[Steve Gibson]

Jim...

Also:

So for example your C3 is short circuited.

YES!!  And in the photo shown, THAT WOULD BE SHORT-CIRCUITING David's tweeter!!

/Steve.

[Kindanyume]

Indeed,.. my old bb from school decades ago is exactly like that..
(and it still works like a charm)

[hausm...@gmail.com]

Got my perf board done, and put it in a box.  I put photos on the finished product under the constructed devices show and tell.   

Dan

[stede....@gmail.com]

I am using a very similar mini board and it's prefect for small one-IC circuits and as a place to attach parts for a microcontroller project.

I really like these flexible wires:

http://shop.moderndevice.com/products/75-wire-breadboard-wire-kit

They have strong, narrow steel tips and are very easy to insert. The insulation at the end, although thick, still allows for wires to be inserted in adjacent holes. They also happen to fit in standard headers and fan connectors perfectly (Elsewhere, I'm playing with PWM control of 4-pin fans).

They also carry mini breadboards and the like:

http://shop.moderndevice.com/collections/prototyping-breadboards-wires

I have a photo over in the build thread that uses the mini board and those wires. The pair is like $8+sh

+s

[Thomas Couey]

Steve,

I know this post is a few days old, so maybe this has been discovered by others (or maybe it's just my setup), but with the v2.2.2 version that I built today removing the C1 decoupling cap causes the overall current to increase by at least 50%. I went from around 30mA with it to 60mA without it. Definitely take a look at that if you consider removing it. Maybe it's an oscillation building up in the MOSFET driver IC? I didn't scope it or anything, I just added the cap back in and watched the draw go back to around 30mA on the power supply ammeter.

/Tom.

On Saturday, January 12, 2013 10:02:51 AM UTC-10, Liquidretro wrote:

I was incorrect in my post yesterday.  The capacitor that I ruined was not C1 but instead C3.  I figure C3 is not necessary so i tied the tweeter to the switch.  It appears I may have a faulty switch which I will replace today but I am assuming I should still get a tone.  I did build the circuit without C1 (that I have) to test it and obviously things are not working.  Wondering if I should go ahead and put it in, and repair the switch or just do the switch.  When I hook it up now, my battery starts to get warm, so there is something not right.  

On Friday, January 11, 2013 2:29:06 PM UTC-6, Steve Gibson wrote:

 

I accidently ruined my C1 capacitor.(A leed came out while unsoldering it)  I was able to find an identical valued one locally, however it's an electrolytic capacitor instead of a ceramic capacitor.  Electrolytic capacitors are polarized, so I was first wondering will this be ok in the circuit?  I know the ceramics are a closer tolerances and better for what we are doing here, but I am assuming this electrolytic one will work?  If it will work, which direction should it go? Or should I just bite the bullet and order another from Digikey and pay a significant amount to ship a $0.38 part.

You probably don't really need it at all.  I'd say give it a shot, using both buttons to verify the REALLY LOUD AND ANNOYING TONE.

It's instinct for me to obey best design practices... but in this application I really doubt that C1 is needed at all.

In fact... I may eliminate it from the design once I have verified that, now that you have pointed it out.

Normally, a "local capacitor" is placed electrically close to any chip that might experience the need for short bursts of high-current... something that ceramic capacitors excel at.  But that's just not needed at all in this design.  The MOSFET driver chip is not driving any MOSFET.  It's just yanking the upper-end of L1 up and down.  And that's an ENTIRELY different task than if it were trying to charge and discharge a MOSFET's gate capacitance quickly.

So... the more I think about it... get rid of it!!  :)

/Steve.

[Steve Gibson]

Tom,

That's GREAT feedback, thanks!!  I will DEFINITELY look into that.

I have a lot of work to do on the v2.2.2 design, since I want to explore changing the inverter to something else, and explore using an inverter without any front-end hysteresis.

I know this post is a few days old, so maybe this has been discovered by others (or maybe it's just my setup), but with the v2.2.2 version that I built today removing the C1 decoupling cap causes the overall current to increase by at least 50%. I went from around 30mA with it to 60mA without it. Definitely take a look at that if you consider removing it. Maybe it's an oscillation building up in the MOSFET driver IC? I didn't scope it or anything, I just added the cap back in and watched the draw go back to around 30mA on the power supply ammeter.

See my posting (near the end of this thread) about some circuit concerns...

/Steve.

[Steve Gibson]

Everyone...

I am concerned that:

1. People are reporting lower than expected voltages across their tweeters. We're seeing reports of about HALF what I think we should.  This is CRUCIAL to loudness since the power output from the tweeter rises with the SQUARE of the voltage impressed across it.  So half the voltage means one quarter the loudness.

2. The low frequency is reporting higher tweeter voltages than the high frequency. If this project was intended to run at the lower frequency, that would be fine.  But it's intended to run at the higher frequency... with the lower frequency as a sanity check.  So lower high-end is the reverse of what we want.

...which I think means...

3. The values for R1 and C2 are not yet optimal.

R1 & C2 serve several functions simultaneously, which is the reason we've managed to succeed with so few parts.

The MAIN purpose is to serve as a delay of about 90 degrees: Consider that, as depicted, the right end of R1 is connected to the top side of the tweeter, and the other side of the tweeter is connected directly to ground. This means that the "input" signal to R1 is the instantaneous voltage appearing across the tweeter. To pick up our drama at an arbitrary point... assume that the tweeter's voltage has been positive and is swinging rapidly negative.  It flies past zero, heading negative by 20 to 30 volts.  This begins DISCHARGING the C2 capacitor through R1... so that the voltage across C2 (which is also anchored to ground) begins dropping.

At some point... IDEALLY just as the tweeter's negative-going excursion levels out at its negative peak and begins heading positive again... C2 will have discharged to BELOW the inverter's switching threshold.  The inverter will see a "LOW" logic input, so it will instantaneously switch its output HIGH.  This is exactly what we want.  Just as the tweeter's voltage is at its lowest point, we want to yank the output of the inverter, which is the input to the L1 inductor, POSITIVE... thus beginning the process of swinging the tweeter's voltage from its most negative to its most positive.

But... all the while that the tweeter is in negative territory, R1 continues to discharge C2, always trying to get it to the tweeter's voltage.  Thus, C2 ends up with a NEGATIVE voltage across it by the time the tweeter's own voltage finally swings back positive and heads towards its positive peak.

As that happens, R1 begins the task of charging C2 in a POSITIVE direction now.  But it's going to take some time, since C2's charge went rather far negative.  And wouldn't you know it... just as the tweeter's voltage reaches its positive-most peak, R1 gets C2 charged back up to the inverter's input switching threshold, the inverter sees that as a logical "1" or "HIGH"... so it switches its output to LOW... thus yanking the input side of the L1 inductor LOW and beginning the tweeter's journey back toward its negative peak.

So... R1 & C2 together form a DELAY.  The time R1 is always taking to charge or discharge C2 is what allows the tweeter to "get carried away", swinging way past zero before R1 allows C2 to "catch up" and get the inverter to switch its output.

But there's something else too:

The VOLTAGE at the RIGHT END of R1 is the voltage ON the tweeter... which we have seen is in the area of positive or negative 20 to 35 volts.  IF that much voltage pressure were EVER to touch the input of the inverter... the inverter would be instantly fried!  So the secondary function of the R1/C2 pair is to serve as an AC attenuator (or low-pass filter) to dramatically tone-down the wildly swinging tweeter voltage to the much lower (+/- 5 volts or so) input range of the inverter.

I would LOVE to have anyone who is curious, motivated, and capable, experiment with the values of R1 and C2.

I had originally (v2.2.0) chosen R1 to be 15k with C2 at 4700pf.  That was optimal for the high-frequency mode.  But it was NOT for the lower frequency mode.  So I increased R1 to 22k in an attempt to compromise between the two.

It's important to realize that R1 & C2 form a FIXED DELAY -- a function of the R1/C2 "time constant".  It's known as a time constant because it's constant in time.  But the circuit would really rather have a very different delay (half the delay in fact) when operating a twice the frequency than when operating at half the frequency.

No one NEEDS to do any of this... as I WILL get back to it soon.  But if anyone is frustrated that their device is not producing as much voltage (and thus loudness) at the high-frequency as at the low frequency, this is likely why.  And it's fixable!  :)

/Steve.

[Gabriel Olinger]

Hello All, very interested in building this device, needless to say I really enjoy the show.

Do you have a BOM I could upload to Arrow? I will be ordering from them today so I thought I'd take the opportunity and add a few things for myself...

Thanks,

Gabriel

On Monday, January 7, 2013 12:51:13 PM UTC-5, Liquidretro wrote:

I thought it might be a good idea (and make things more clear) to create a new thread dedicated to V2.2.2 Construction.  This will allow us to keep discussions here separate from the microcontroller version and answer peoples questions as they receive parts and build.  

[Steve Gibson]

Hi Gabriel...

Hello All, very interested in building this device, needless to say I really enjoy the show.

Do you have a BOM I could upload to Arrow? I will be ordering from them today so I thought I'd take the opportunity and add a few things for myself...

http://www.grc.com/tqc/LatestDesigns.zip

That link contains the latest designs.  What people have been building is the v2.2.2 design.  It's subject to some further change, but at the time it was the best I knew how to create.

The Bill Of Materials is for Digikey.  But you can use the Digikey part numbers to find the manufacturer's... then drop into Arrow for theirs!  :)

Have fun!!

/Steve.

[birr...@gmail.com]

Hi Everybody!

I need your help regarding my build of the The Treble Shooter. I got all the necessary accessories and I put the circuit together on a breadboard. Everything was straightforward except maybe for the piezo tweeter; I eventually went for the KHS 107 because it was the smallest in size (300W/4ohm, 150W/8ohm, 5-20 Khz, 104 dB).

The circuit is working, but the sound I get is very very loud and deafening. I took it to a friend who has an oscilloscope and he told me that the output is somewhere around the 10 Khz area. So, it's audible by humans and I personally have the feeling that whenever I push the button a thousand braincells of mine die per second. It's really-really loud and bad for the ears. Trust me, I'm not exaggerating!

First of all I would like to know what I did wrong, if any. Secondly, my friend told me that C2 which has a value of 4700 pF should be smaller, e.g. half the size, in order to increase the output frequency or a smaller inductor should be used. What do you think of these statements?

I'm really looking forward to your suggestions. Please help! I can't test this THING like this anymore. :-)

By the way, I did a hearing test on the website of University New South Wales (do a search for it if you're interested) and I could hear the 16 Khz sound quite well, but that was by far not so annoying than I'm getting from my Treble Shooter build.

Cheers,
Robert

PS: I can post a few photos of the circuit on the breadboard if that helps, it's just that it will be hard to tell anything about it through a photo since there are many small cables involved; please let me know and I'll do my best.

[steve cirelli]

There should be two buttons. Press one for the 8khz tone, press them both together for the 16khz tone.

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[sigpoggy]

It sounds like you have added capacitance to the output. When wired properly this occurs when you press S2 which is normally open.

If pressing S2 does not cause the frequency to drop, you have a wiring problem.

If pressing S2 causes your output frequency to drop, then perhaps the tweeter is the cause. I have found that changing the feedback RC circuit (C2 and R1) causes very little change in frequency. The tweeter capacitance and the coil really determine the frequency. That is why adding the 0.22ufd cap across the tweeter (using S2) cuts the frequency in half.

[Kyle Smith]

Robert,

I'm somewhat confused by the spec you cite for the tweeter that you used.  You give wattage spec's for both 4 and 8 ohms, which sounds to me like a specification for a standard electro-magnetic speaker, while piezo tweeters appear as a capacitor to the circuit, and therefore would be more typically rated in pico-farads, and at any rate you would not be able to change it's impedance, the which depends on the temperature, and frequency of operation.  Perhaps they are specifying impedance of a standard speaker, to which you place the tweeter in parallel, and then those wattage values are really not the power absorbed by the piezo tweeter, but rather the standard speaker that they shunt.

In any event, you will need to determine the characteristic impedance of your piezo tweeters, before you adjust any of the components, since the circuit was designed and highly tuned for a piezo of a very narrow range of capacitance.  Most multimeters will allow you to measure the capacitance of your particular tweeter.  This should allow you to compute any necessary changes in the capacitive load seen by the rest of the circuit.

And now I'll allow other builders to comment on the specifics, as I have yet to build any of Steve's designs.  I'm awaiting encouraging data on their effectiveness before I break out the soldering iron.  Actually, I rather more interested in another thread, where builders are experimenting with placing a piezo tweeter or bender at the closed end of a 1.5" PVC pipe, usually cut to something less than a foot, as a means of giving the tweeter's/bender's output a great deal of directionality, with the hope of extending the effective range the device.

Finally, I will give my usual caution about high volume audio.  If you sense you are having damage done to your hearing as a result being in close proximity to one of these devices, you are not alone.  You should take steps to protect yourself from being exposed to the direct blast from the tweeter.  Some have placed the tweeter horn side down into a folded towel; but you may need even more protection.  If it is uncomfortably loud, it is too loud for you, and you should do anything required to reduce the volume, to protect your hearing, which can be permanently damaged from even short durations of exposure to excessive sound levels.  When in doubt, please consult your physician for the best information.

Best wishes,

 

--kyle AG2F

Kyle Smith, MS, MD (retired)

air...@me.com

[sigpoggy]

I always wear earplugs when testing. The cheapest, most comfortable, and easiest to find are the foam type - good for about 30 db of attenuation. Can get at your local drug store.

[Steve Gibson]

Congratulations on getting a LOUD result Robert!

That KHS107 looks like a very nice and very sturdy choice:

http://www.price.ro/specificatii_sal_tweeter_piezo_khs_107_295859.htm

Since you aren't using one of the typical KSN1005 tweeters, whose capacitance we know is about 0.15uf, it might be that your tweeter's capacitance is higher, thus the system's oscillating frequency is lower.

(Though you'll want to follow everyone else's advice also about making sure you've got the second button connected correctly.  Whatever else is happening, when you also hold the second button depressed THAT will drop the system's operating frequency to where it's VERY loud and easily heard by people.)

The ONLY solution for fixing the frequency will be to LOWER the inductor's value to compensate for the tweeter's higher capacitance.  You'll want to choose a similar power inductor with a resistance of around 1 ohm.  And it "sounds" as though it ought to be somewhere around 625uH in order to bring the frequency back to around 16khz.  680uH is a standard value... so that's what I'd recommend.  :)

/Steve.

[Kindanyume]

Ahh once again the uber wise SG rulez :)

[birr...@gmail.com]

Hello!

Thank you very much for your feedback! It feels good that several of you responded. My beast needs to be tamed! :-)

Allow me to respond to your messages one by one.

@Steve Cirelli: I have both buttons. If I press S1 I get the higher pitched sound and if I press S2 while holding down S1 then I get the lower pitched sound. So, everything's fine in that regard.

@sigpoggy: As mentioned above, for S2 to work I need to hold down S1. I believe that means that the wiring is correct. I guess that my friend was right about 'too much' capacitance, but if what you say is true then changing C2 won't do the trick. And thanks for the tip about the earplugs; I think I have a couple of Hearos branded ones lying around.

@Kyle Smith: I don't know what to say about the wattage specs of the tweeter, so you're probably right. I found that info online, but unfortunately I didn't found anything about its capacitance. I'll see if my very primitive multimeter can measure capacitance, though I'm 99% that it can't.

@Steve Gibson: I'm pretty sure that the second button is connected properly, but just to make sure, I'll tidy up the circuit so that it's followable on the breadboard too, make a few photos and post them here or in the 'show and tell' thread. In the meantime I'll search for other types of inductors too, specifically the one that you recommend. If I don't find one, I might ask my friend to help me uncoil let's say half of the wire off the current inductor and see if that helps.

After doing the hearing test, I think I would be happier if I could operate my device higher than 16 Khz, maybe 18 or 20 Khz. I only want to hear it when pressing the second button. I will post back with my findings soon.

Only the best,
Robert

[birr...@gmail.com]

Hello!

How about a a 680 uH / 2.2 Ohm inductor? I could get this shipped in a few days from a friend of mine. Otherwise I would have to buy from eBay again and stay idle for 4+ weeks until the package arrives from China...

Please excuse my lack of knowledge. I should know if a higher impedance inductor would affect the circuit, but that's not the case yet.

Kind regards,
Robert

[Steve Gibson]

Robert...

Perhaps you could get both?  The 2.2ohm inductor for now and the lower resistance inductor for later?

In our circuit you can think of three items connected in series:  The 9v battery, the inductor, and the tweeter.

We would like to lose as little power in the inductor as possible, and also put most of the voltage across the tweeter.  So as a general rule of thumb... the lower the resistance of the inductor, the better.

It will likely NOT make a huge difference, and I haven't experimented with that.  But I always work toward the optimum.  :)

/Steve.

[Steve Gibson]

Ahh once again the uber wise SG rulez :)

That's kind of you.  But I'm annoyed that I have been forced to stall my work for these past few weeks.  I'll be back as soon as I can!

/Steve.

[birr...@gmail.com]

OK. What I did today was I took and old satellite receiver that will not work anymore and I checked all the ceramic caps in it. I took the highest rated pF cap (i.e. 561J, that is 8.3 times smaller than 4700 pF), unsoldered it and put it in place of C2 in my circuit. Result: pressing S1 no sound, not humanly audible at least; holding down S1 and pressing S2 a very high pitched sound was emitted. If I had an oscilloscope I could calculate the frequency, but since I don't I only have guesses regarding this result: 1) by pressing S1 such a high freq sound was emitted that it was not audible by me or maybe the tweeter couldn't handle it and 2) by pressing both buttons the freq dropped to an audible level (my rough guess is that it was around the 15-16 Khz value).

Conclusion: playing with C2 DOES have and effect on the output sound frequency. If I knew the math/equation or had an oscilloscope I could probably calculate the right capacitor value for a given frequency.

I'll get a hold of that 680 uH 2.2 Ohm inductor and make tests with it. Once satisfied with indoor results I'll test it outside, then find a case for the device, make the PCB and put everything together. Sound like a plan, huh? :-)

Photos attached. I'll be waiting for your feedback. Thanks! Have a nice night (GMT + 2)!

[Steve Gibson]

One more thought...

I forgot to to mention that your idea of "unwrapping" some winding from the 1mH inductor is a GOOD ONE!  That would be very effective in reducing its inductance and INCREASING the system's operating frequency!

/Steve.

[François Pominville]

Just tested 10 cheap piezo horn:

They are listed as SH-307

Piezo 3-3/8"

40 W RMS

Freq : 4 KHz - 27 KHz

103 dB

I paid 3$ each, and tested them with v2.2.2 and 6 of them oscillate at around 15500 Hz but the 4 other ones oscillate from 12500 Hz to 13500 Hz, so I will have to compensate with a capacitor if I use the "bad" ones, but they all work at least.

[JohnB]

Relationship between circuit components and resulting frequency.
Based on some testing I have done, it looks like a lot of adjustments are possible by using just a couple of different values for L1 and adding a second tweeter either in series or parallel. The table below summarizes my results. ( I hope the formatting translates in to this thread, otherwise it may be hard to follow).
I have not tested to see what effect the second tweeter has on dB level.
  





TQC – Relationships Between Components and Resulting Frequency

L1 (uH) C2 (pF) f (kHz)
Goldwood horn – single
1000 4700 15.5


1520 4700 11.7


680 4700 17.5






Goldwood horn – two in parallel
1000 4700 9.9


1520 4700 8.6


680 4700 12.2


680 350 16.1






Goldwood horn – two in series
1000 4700 21.5


1520 4700 16.9


680 4700 26.8






Pyle Surface Mount – single
1000 4700 16.4


1520 4700 14.3


680 4700 20.7






Pyle Surface mount – two in parallel
1000 4700 10.9


1520 4700 9.3


680 4700 15.3






Pyle Surface Mount – two in series
1000 4700 25.1


1520 4700 20.7


680 4700 30.0






41 mm
1000 4700 20.5


1520 4700 17.1


680 4700 26.0

[cbra...@gmail.com]

Using a second tweeter reminds me of some of the work Woody Norris did where he takes 2 high frequency audio signals and points them at something.  The sound is inaudible until the 2 wave forms converge off at a distance, but when they do, they blend and the resulting wave form is audible.  The entire idea is fascinating to me.  If you were able to produce something like that I'm pretty sure it would have a dramatic affect on any animal (or person for that matter).  The problem is that from what I understand, this is VERY directional.  The current version is like a hand grenade, and this would be more like a sniper.  It's supposedly so directional that two people can be sitting on a couch next to each other and one person can hear it a full volume and the other person can't hear it at all.  I find that hard to believe, but something like that would be lots of fun to play with if you had a noise dog and you wanted to freak it out without disturbing any other animals or people nearby that might have good enough hearing to pick up the 15 kHz frequency.

[JohnB]

The beauty of the v 2.2.2 circuit is its simplicity. Since C1, S2 and C3 are not needed for the basic system, it's only about $8 worth of off-the-shelf parts. You just turn it loose and it runs the way it wants to. With that simplicity comes a lack of adjustability that has made resonance and directionality elusive and maybe unachievable. The hand grenade analogy is not a bad one, and I would love to see the researchers here develop the ideas for a rifle that focuses the impact on a limited area. My basement "lab" hasn't provided any encouraging signs in this regard, and the other TQC threads haven't either unless I missed them.
The Woody Norris work was fun to watch on You Tube and intriguing enough to suggest a couple of experiments, but something tells me a couple of $2 oscillators and $2 piezo tweeters aimed at the same point aren't going to catch up with him. In any event, it's another research angle to try so thanks for the idea.

[Kyle Smith]

Hi John,

Woody Norris did something quite amazing, for which he received a patent. If you look at his product specs, however, you'll not that the sweet spot is quite close, within just a few feet. That's why it can work in a kiosk setting, where the whole system is ceiling mounted, and only needs to reach the listeners ears, a few feet down, while rolling off some 20db just a step to the side.  Great for museums and expos, but not a good design for targeting an upset canine, without getting to close for comfort.  Interesting also, was his statement about his competitors, where he states that all speakers become more directional the larger their size.  As with many things in physics, this does not seem intuitive to me, but I will differ to Norris on the matter.  If he is correct, that says something about the approach that has been proffered, to use these very small diameter PVC tubes, in order to increase gain, in the forward direction.  Steve suggested at one point that a large concentric array of these tweeters might do the trick.  It's just possible his suggestion to construct a bazooka sized array of tweeters is the correct approach, for reasons he may not have been aware of, but then he's Steve, and he's usually ahead of the pack, and this might have been his thinking all along.  Of course, it wouldn't make for a very portable, or discreet device.  Another thought would be to use standard high frequency drivers, of a very large dimension, and place them in 3" tubes.  My other thought would be the use of the quite expensive pleated tweeters, which have a rectangular form factor, and can be quite large in size.  

Finally, one should never underestimate the volume that can be achieved with compressed air, when suddenly allowed to escape thru a well designed horn or whistle. Just think of the volume created by a simple hand pumped pellet rifle, when the missile leaves the barrel at >1600' per second.  Now that will get a dogs attention in a hurry.  They actually sell these CO2 canister powered air horns that are meant to be fitted on a bicycle. The details are back in an obscure post I wrote some time ago.  At the time, I thought to myself, that it would be interesting to fashion an apparatus that vented a CO2 cartridge through high pressure tubing that terminated in a standard dog whistle.  I don't know how the excessive low pressure produced at the whistle slit would effect the frequency and volume, but it would be a blast to check it out.  Sorry, couldn't resist.

I now return you to your regularly scheduled programming. 

Best wishes,

--

Kyle Smith, MS, MD (retired)

air...@me.com

--

[s c]

Hey everyone,

I know nothing about the electrical components other than what a basic cap and resistor does so needless to say I’m a complete n00b at this but figured I wanted to try.

I have built a pdk v2.2.2 and I’m not sure of the results other than all 3 of my does did not blink an eye but my 24yr daughter did react to it while I was testing it.

I have taken some photos and 2 quick videos with and without s2 in the circuit.

At this point I’m happy to have tried this out but I have that ”is that all it does” look on my face  :(

I’m not sure what to expect, and was wondering if someone could look at the videos I posted and tell me if the output you hear is what one would expect.
Also in the photos are the digikey parts list as well as a pic of the tweeter I used Pyle PSN1167.

The photos/videos are at:

https://plus.google.com/photos/106054191180279283701/albums/6055763739200183361?authkey=CPzSnuvR49bnOg

 

Thanks to Steve and Leo for all the great shows as well as to everyone in the community…

 

 

[alice...@gmail.com]

I'd like to use a Raspberry Pi to remotely activate a TQC v2.2.2 system (replacing SW1).  In addition to the RPI, what would I need to interface an RPI with a TQC v2.2.2?  Would something like a SainSmart 4-Channel Relay Module allow me to control TQC?  Since I've ruined an RPI hooking it up in a similar situation I'd rather do this smart this time.  If a relay module is not the way to go, what should I use so I can replace SW1 with a GPIO activation on the RPI?  I'm pretty sure I shouldn't connect the RPI GPIO pins as a direct replacement for SW1.

[reza....@gmail.com]

I finally got around to building a 2.2.2.... my soldering iron doesn't work so I left it on the bread board for now.  An old cigar box was perfect in size!

[reza....@gmail.com]

and here is a vid: https://www.youtube.com/watch?v=SfDGTGDsvws&feature=youtu.be

[davec...@gmail.com]

Am ordering parts from digikey and I note that of L1, digikey gives the status "Part Status: End of Life; Last Time Buy Date: 12-22-2016. Minimums may apply."

Just FYI. Might want to look for an alternate, for example 732-3261-ND ??

Also the little breadboard mentioned above, 700-00012-ND, is back-order est. 17 august ship.

[Jay Salsburg]

The TQC_v2.2.2.pdf schematic appears to be a relaxation oscillator. What is conspicuously absent are photos of Breadboarded prototypes, Oscillographs of test points, and Videos of the device being used.
I hope my reply gets a response. I am an Electronics Engineer. This is an interesting project but there is no clear documentation other than the schematic and BOM. What I a need to experiment with this project are Timing and Waveform oscillographs or screenshots. Since there are literally hundreds of posts, there is no way I can read all of these to discover any Engineering Analysis. Seems like a 555 timer would probably be preferable for a control device. 

[girard...@gmail.com]

Nice build! How effective is it to stop the canine barking?

I'm in the process of assembling one unit, I'll post pictures once I'm done. I'm living in the Philippines and there are plenty of dogs around our house barking day and night! I was not able to find U1 locally and had to order it from the US. I also wasn't able to find the recommended tweeter, so we will see if the one I found will work as well.

For anyone wanting to save a bit of cash on the build, you can order free samples of the TC4421A from microchip's sample site: https://www.microchip.com/samples/ I was able to order 3 of them for free as spares in case something went wrong...

Cheers!

[Kindanyume]

thnx for that info

as for the speaker.. I got a small box of them from a different supplier..  so anyone up in the Hamilton ON area that wants them they are much cheaper than having them shipped in from the US. (shipping cost from there is insane as a rule)

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