The Portable Dog Killer / Quiet Canine Competition

[blankfield]

Hi Tomaz,
I got nice results with self made step-up transformer HERE, one big advantage of this configuration is no need for series capacitance with piezo. Transformer cuts constant component of signal. You asked about square wave, for this application square wave is the best solution, sure it will add some harmonics on output (you will be able to hear some white noise but just a little bit)  but on the other side you will get 100% of power at this supply voltage.

[MJLorton]

I'm really chuffed to see the progress and sharing ideas...please keep it up!

Cheers,
Martin.

[MJLorton]

Folks....let me know....would you like a bit more time or wrap up at the end of Feb? Remember, I'm not the judge so you'll need to post some kind of presentation or video of your device / work so others can see it.

Thanks again for participating in this one.

[birrbert]

Hi!

I personally think that a bit more time would be great. I'm waiting for some more components and with those I can finalize the device, then I'll try to make the video, but I have no idea what to make it about. Anyway, I'm definitely finishing it during next week and hope to have some video by Thursday of Friday.

Will there be only one prize? How about first prize and second prize rather than giving it all for one? Just a thought.

[blankfield]

Like for me one week is enough time to finish my project but if someone needs more time I do not mind the extension of the contest deadline.

[MJLorton]

Ok, let's extend to the17th of March so you have that weekend to complete and produce some little video / presentation on how you produced the device and if possible show its operation.

Judging will be opened to viewers and forum members from the 18th to the 21st...with the winner being announced on Friday the 22nd of March.

The prize for the winner is goods to the value of $150 from Amazon and a UNI-T UT61E...the runner-up will get a UNI-T UT61E.

Cheers, Martin.

[circuitous]

Here's my first attempt:
Vision:
One or more remote controlled devices(annunciators) which will emit a high frequency audio pulse.  One or more remote transmitters that can trigger all remote annunciators simultaneously.

Principle of operation:

• Transmitters will use the 315MHz ISM band.  The transmitters will all use the same address/code.  Matching ISM receivers, all set to the same address/code.
• The audio frequency is not critical, and will sweep across a range of 18 - 22 KHz. 
• The audio will be generated by a PWM from a microcontroller.
• The audio burst should be 3-5 seconds in duration.
• The PWM signal from the microcontroller will be sent through a 2N2222A to a piezo speaker with a parallel inductor to boost the voltage.
• The device should be able to run on 5 VDC.
• The device does not need to be battery powered, so standby power consumption is not critical.

Components:

• RF remote transmitter:  keyfob remote from Adafruit.com - based on the PT2262
• RF receiver:  Simple RF T4 momentary from adafruit.com - based on the PT2272
• Picaxe-08M2  - why?  had one laying around
• Speaker:  piezo tweeter
• Power Supply - 5V USB plug-in

Circuit:

Screenshot from my DS4024:


And, here's the code:
; Bark Controller
;  initializes LED and Piezo to OFF
;  waits for a signal
;   when a signal is received:
;     turn on LED
;     step through a set of 3 tones, 10 times
;     turn off the LED
;     turn off the sound
;     wait a couple of seconds
;
; Tones to play:
;   frequency 18Khz = pwmout C.2, 55, 111
;   frequency 20Khz = pwmout C.2, 49, 100
;   frequency 22Khz = pwmout C.2, 44, 91

low C.4   ;LED is C.3 = PIN 2
pwmout C.2, off  ;Piezo is C.2 = PIN 5
do  ;input is C.3 = PIN 4

 if pin3 = 1 then
  high C.4 ;LED on
   For b0 = 1 to 10
   pwmout C.2, 55, 111 ; 18Khz
   pause 100  ; play for 0.1 seconds
   pwmout C.2, 49, 100 ; 20Khz
   pause 100
   pwmout C.2, 44, 91 ; 22Khz
   pause 100
   next
  low C.4
  pwmout C.2, off  ; turn off the piezo
  pause 2000
 endif

loop

EDIT: corrected frequency in code comments.

[RiccardoGiuliani]

Notifications failed to send emails to me, so now I'm reading some new interesting posts. 
Glad to see the new end day.

I had got some time to quickly extend the ne555 astable configuration with an H-Bridge of general purpose bjts like in photo: the core of two couples of npn (top) and pnp (bottom), with two external, npn and pnp respectively to command the alternated opening and closing of the core.
My intent was to (quite) double the output dynamics, but without an oscilloscope I'm not sure about the result: what I can state is that the test I made today with a little dog met on street has totally failed.
The dog did everything but to run away.

Maybe the power supply change (from bench one to 9V battery) didn't give enough power; I don't know.

About the output frequency: I regulated the pot to get a 30KHz, as measured.
After that I measured on pin3 of ne555: got 60KHz.
So I replicated the basic astable circuit and I found the same values: 30KHz on transducer and 60KHz on pin3.

Bye

[tomaz]

Hi all,

first thanks again for help and ideas

I have tried and failed, but here is my video of experiment of doing and testing portable device - with other words, I don't like the result, even if it is partially working Output volume is too low.
The idea was, to put everything in a nice small box, but till is not satisfactory working, it would be waste of time.

Here is youtube video made from few pictures (borring:):
http://www.youtube.com/watch?v=O3Wc_PFm0m0

and here is all the action - testing new portable device: http://www.youtube.com/watch?v=wHkwlRPfzRo


H-Bridge idea was from one pdf, which I don't have on this laptop, but it is similar to this: here - btw output pin on right 555 is 3 and not 2.

On the end I noticed that one transistor and few small inductors do the same job with all three piezo tweeters I have.

Solved: variable input voltage -> on the output: different frequency - solved with 7805, thanks

New question:
 - how to compensate temperature change of environment to have all  the time same output frequency?

Thanks to blankfield, SeanB and dr_p I have learned just by experimenting that transformers have different input/output ratio not just by number of turns, materials,... but also from input frequency. I have tried few random transformers I salvaged from old devices and output voltage was differently on different input frequency...

Sorry I had to finish my development/improvement on 24.2. since I had to go away for 4 weeks -  health treatment. But I'm really interested in what people will create here:)

Next thing to do: buy new better speaker:)

Regards,
Tomaz.

[blankfield]

Hi Tomaz, really nice video especially this secret weapon in bag, and a pair of pliers as jumper :-) like my quick tricks. I'm suspecting that you are using wrong type of transformer core, probably Iron dust type, more useful for filters and less for power, but this is only my suspect. I did same mistake at beginning so it's worth to check this.

[blankfield]

Hi all,
There is a time to write about final results of my project, this week will be very busy for me so I've decided
to write some description now. First of all I want to tell you about my challenges with this project,
now I know - output power is the most important factor to make a device meeting the job.
My unit produces almost 10W RMS output power (measured with audio output power meter with bandwidth
up to 22kHz) (0,95A @ 12V @ 20kHz) it's enough to intrigue dogs in range about 5m but not more.
Noisy dogs in my neighbour  stops barking only for some while. My next step will be rewinding transformer
with thicker wires to use a maximum power of battery pack. Now I drain battery at 4A current level (@4,1V)
so it's low value like for 8 Li-ion cells, some space for improvements is available . Another fail like for me
is bark detection now is working like analog comparator realised via ADC interrupt, my attempts to realise some
DSP takes to much energy and MCU power so I decided to drop my plans. I found really nice program to design
digital filters - WinFilter easy and works! In present configuration standby power don't exceeds 900uA which
is great result. My observations led me to set frequency below 20kHz I think that cheap piezo have huge drop
of power above 20kHz, my piezo speakers are affected by this effect.
but

Block diagram.


Final schematics.


Some internal mess:-)


Assembled portable bark killer.



Output waveform loaded with 4 piezo speakers.


Output waveform shape unloaded.   


A new position in my watch menu.


At last I did some cell phone video, sorry about poor quality.
http://youtu.be/fhTo13PFoFI

Some source code.
Portable Bark Killer - firmware
Watch - firmware

All my other messages describing progress from sketches and experiments to the working device can be traced here:http://mjlorton.com/forum/index.php?topic=182.0.


Regards,
blankfield.

[MJLorton]

Hi Tomaz, really nice video especially this secret weapon in bag, and a pair of pliers as jumper :-)

Yup...I second that...I was in hysterics watching it!

Great post Tomaz...even if the device did not work correctly...it was wonderful to see the "covert" effort in testing it.

[MJLorton]

Blankfield....thanks for your great post and video. Good luck good man.

Cheers,
Martin.

[birrbert]

Howdy!

Here's my video too (HD Ready): http://www.youtube.com/watch?v=GjnFq6fCXwk (7:38)

As mentioned before, my device "shoots out" roughly a 20 kHz sound. Although none of the "test subjects" were afraid of it, I'm sure that they heard it; four of the dogs were strongly guarding their master's territory and the fifth one was so friendly that it came close in hope of some snack. Besides them there were several other dogs that I tested in secret (I wasn't brave enough to film it since their owners were too close).

For added fun, I included a spectrum analyzer too.

I definitely had fun during this project. I learned a lot about electronic components, practiced soldering, sound and video editing and most of all how to be creative. As a final conclusion I would say that my device needs more power, this 20 kHz sound needs to be louder. I am 100% positive that it wouldn't help much if there was no fence between me and the animal guarding the place.

Photo album: http://www.flickr.com/photos/birrbert/sets/72157632916200092/
Read about the concept here: http://www.grc.com/tqc/TheQuietCanine.htm
Latest designs (bill of materials and schematic): http://www.grc.com/tqc/LatestDesigns.zip

A big thanks to the following people:
- Steve Gibson, for the detailed schematic, bill of materials and continuous help
- Martin, for raising awareness about Steve's concept, involving and challenging us through a giveaway competition and moral support
- Tom Pascale, for playing the Entertainer on a piano and making it freely available on pianosociety.com

Software used to create the video:
- Corel Video Studio X6 Pro
- Virtual Dub
- WinAmp
- CamStudio

[blankfield]

Great video birrbert! Mr. Curious reacts similarly like my dog, his eyes saying "why you doing me this".
I'm looking forward for other entries, maybe somebody will inspire me to improve my design. I would like to increase effective range before summer. Will be nice to have undisturbed sleep during summer:).

Cheers,
blankfield