ultrasonic dog repeller - Page 1
Forum section: electronics / projects

author: akis
author_rank: Frequent Contributor
timestamp: June 29, 2014, 12:51:29 pm
content: I want to design and build an ultrasonic dog repeller. I have been on Amazon and the reviews for the ready made ones are not good. I think it is a matter of power.Therefore I want to make something so powerful it would blow holes out of the fence. It does not need to be battery operated, I can run a long wire to it.So I bought two cheap tweaters on ebay, when they arrived they appear too small and plasticky, was expecting them to be metal and heavy.Anyway I was thinking one or two oscillators at 30KHz and 50KHz to alternate, and a power amplifier to drive the tweaters, we need a lot of watts here, I am not sure how power RMS translates to audible power at these frequencies.If anyone has ever worked on a similar project please let me know. Something 100x as powerful as those handheld ones sold at Amazon.

author: Zepnat
author_rank: Regular Contributor
timestamp: June 29, 2014, 01:02:53 pm
content: Can't you use an electric fence i don't know anything about these repellers but can't imagine it working very well unless it was painfully loud by then every other creatures ears would be ringing and maybe damage your own too. Maybe the sound can be directed somehow.

author: Andy Watson
author_rank: Super Contributor
timestamp: June 29, 2014, 01:06:11 pm
content: I am toying with the idea of building something similar - there is a dog that lives a couple of doors away that howls its head-off whenever the owner goes out. I'm torn between making an ultrasonic device, or launching the dog into the middle of next week on the end of my boot.I believe the optimum range for dogs is in the 20-30kHz region. And don't be fooled into thinking that these U/S devices are not very powerful when you can't hear them!/www.grc.com/tqc/TheQuietCanine.htmSomewhere on the web is a video/vlog/chat-show interview with a guy (I think it was Steve Gibson) that describes making a battery powered ultrasonic dog blaster.edit:https://www.grc.com/sn/sn-248.htm

author: akis
author_rank: Frequent Contributor
timestamp: June 29, 2014, 01:14:37 pm
content: Andy, we are neighbours.I have just tried my amplifier and the ebay tweeter on my cat. Frequency 60KHz, I rms = 158mA, V = 6V rms , total power on tweater = 0.9W.The cat will run away at about 2-4 metres and directly in the view of the tweater. She will sit in adjoning rooms quite happily.The tweater says 150W, but anything over the power I have described above and it starts to make audible, crackling noises. Maybe I need to buy a proper horn tweater, not that cheap ebay crap.Anyway, the cat is now scared and out of the house. I presume I need much much more power to cover the distance I need (neighbours dog, at least 50 metres away).

author: akis
author_rank: Frequent Contributor
timestamp: June 29, 2014, 01:23:03 pm
content: Quote from: Zepnat on June 29, 2014, 01:02:53 pmThe dog barks in his own garden. I am not even sure I have line of sight. Various solutions that I have come up with include a CO2 laser, my old trusty 5.5mm air rifle, a 10,000 watt ultrasonic machine, claymores (hard to get in the UK), portable grenade launcher (again, this is a US only solution)...

author: Andy Watson
author_rank: Super Contributor
timestamp: June 29, 2014, 01:31:40 pm
content: Quote from: akis on June 29, 2014, 01:14:37 pmI think we might be. The dog has been very quiet since you reported testing your amplifier!

author: akis
author_rank: Frequent Contributor
timestamp: June 29, 2014, 01:48:46 pm
content: I have managed 5-6 Watts out of the tweaters. Obviously we need 100x power.It seems they have done what I am trying to do even down to the selection of the tweaters., but I cannot see anything on this page (and others)can you?https://www.grc.com/tqc/TheTweeter.htm

author: Dago
author_rank: Frequent Contributor
timestamp: June 29, 2014, 01:59:20 pm
content: Here is an ultrasonic bird repeller in action:

author: mij59
author_rank: Frequent Contributor
timestamp: June 29, 2014, 01:59:43 pm
content: Hi,How about this ?http://en.wikipedia.org/wiki/Long_range_acoustic_device

author: SeanB
author_rank: Super Contributor
timestamp: June 29, 2014, 02:01:53 pm
content: 150W rating on the tweeter is that of the associated mid and low frequency speakers in the system. Most tweeters can only handle about 2-5W of power, as they typically do not need much input to get a usable SPL to your ears. Put 10W in and they will definitely fry the coils, as they will be massively overdriven. If you use a piezo tweeter ( does not need a crossover to connect to the amplifier, just directly across the voice coil, typically 2010nF capacitance across the terminals) you will have to drive it with 50-100V to get maximum power out of it, easiest to do so with a small boost converter to give the voltage and a half bridge to drive it. You probably will not need a coupling capacitor as the tweeter is essentially a ceramic capacitor.

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: June 29, 2014, 02:37:56 pm
content: I was going to build something myself about 6 months ago but never got round to building anything as the local chav ,who`s bull terrier drove the neighbours crazy had it stolen, har .My idea was to use a battery powered aquarium pump and just attatch a tube to a dog whistle .

author: akis
author_rank: Frequent Contributor
timestamp: June 29, 2014, 03:14:51 pm
content: Excellent idea. On another forum someone suggested a pneumatic siren. Now that would be loud. And searching on the net reveals that the problem of neighbours' gods barking and ultrasonic repellers is very well researched. You tube shows canons made of telescope tubing with tweeters mounted inside, effective range 30 metres. But nothing would beat the pneumatic siren.