Dog repellent
The electronic dog repellent circuit diagram below is a high output ultrasonic transmitter which is primarily intended to act as a dog and cat repeller, which can be used individuals to act as a deterrent against some animals. It should NOT be relied upon as a defence against aggressive dogs but it may help distract them or encourage them to go away and do not consider this as an electronic pest repeller.
The ultrasonic dog repellant uses a standard 555 timer IC1 set up as an oscillator using a single RC network to give a 40 kHz square wave with equal mark/space ratio. This frequency is above the hearing threshold for humans but is known to be irritating frequency for dog and cats.
Since the maximum current that a 555 timer can supply is 200mA an amplifier stage was required so a high-power H-bridge network was devised, formed by 4 transistors TR1 to TR4. A second timer IC2 forms a buffer amplifier that feeds one input of the H-bridge driver, with an inverted waveform to that of IC1 output being fed to the opposite input of the H-bridge.
For more electronic dog repeller circuits check the related links bellow.
Cat and dog repellent circuit diagram
This means that conduction occurs through the complementary pairs of TR1/TR4 and TR2/TR3 on alternate marks and spaces, effectively doubling the voltage across the ultrasonic transducer, LS1. This is optimised to generate a high output at ultrasonic frequencies.
This configuration was tested by decreasing the frequency of the oscillator to an audible level and replacing the ultrasonic transducer with a loudspeaker; the results were astounding. If the dog repellent circuit was fed by a bench power supply rather than a battery that restrict the available current, the output reached 110dB with 4A running through the speaker which is plenty loud enough!
The Dog and Cat repellant was activated using a normal open switch S1 to control the current consumption, but many forms of automatic switching could be used such as pressure sensitive mats, light beams or PIR sensors. Thus it could be utilise as part of a dog or cat deterrent system to help prevent unwanted damage to gardens or flowerbeds, or a battery powered version can be carried for portable use. Consider also using a lead-acid battery if desired, and a single chip version could be built using the 556 dual timer IC to save space and improve battery life.
Join the forum discussion on this post - (1) Posts
about 1 year ago
I want to build a dog repeller circuit like this.. can you give me a part number/supplier for the ultrasonic tranducer. I can’t find anything small (1 inch diameter) that goes into the 40KHz range.
about 10 months ago
Hi dude, nice schematic. Forgive me if I’m mistaken, but isn’t pin 2 of the 555 timer usually the input and pin 3 the output?
IC2 has pin 2 connected to the bases of TR2 and TR4 and it might turn on TR4 but I don’t see it being able to turn on TR2 unless pin 2 can also become an output.
Same thing with pin 3. I don’t know how IC2 can be triggered if the input is connected to the output.
What do you reckon?
about 8 months ago
I built it & it didn’t work. then I noticed the same thing; output of IC2 is no.3 should go to base of TR2 & TR4 so I switched # 3 & #2 on IC2. I tested with 5, 12 & 17 voltDC power supplies. TR2 overheats with 12 volts, TR 1, 3 7 4 remain cool. AC output voltage of IC1 was 7.7 volts. AC output of IC2 was 9.7VAC
Meanwhile squirrels came & ate most of my red currents. I was going to use it to repel them
about 6 months ago
GARFY DID YOU BUILD THIS CIRCUIT AND DID IT WORK?I READ ALL THE POSTED COMMENTS AND I WOULD LIKE TO BUILD ONE.
THANKS CHUCH
about 8 months ago
Hello again,
Made a mistake on the first message.
It should have read 100 watt nor 10,
Regards
,Garfy
about 3 months ago
Does anyone has a sample of the circuit board for this? Or ya all used wires
about 1 month ago
The Circuit can be built on stripboard quite easily as layout of components is not that critical, but attention must be paid to polarization ie make sure the 556 dual chip or 555 chips are placed in polarised sockets, so you dont have to remember where pin 1 is etc, and mount them last to save heat from the iron reaching them. The Transistors can also be substituted for other similar types. I mounted them on a 6 x 4 extruded heatsink, all insulated of course, which made the housing space a little larger, but I disguised it as a bird nest box so that the neighbours wont know what I am up to, as the unit faces their garden toward the place where their dog continually barks. The dog hasn’t barked for about two weeks so now so I will try turning it off. Its a good idea to incorporate the switch so that the unit can be switched on/off [especially if a dog only barks at night], it can be turned off to save power during the day if batteries are to be used, but mine was on continuously, run from the shed supply with a stabilizrd supply. If you have a scope set the frequency to just below 25Kz. This works for me but you may have to fiddle with the frquency a little for smaller dogs as their hearing range is a touch higher. Hope this helps. HL.
about 1 month ago
Hi HL,
Did you build this circuit and did it work?.
In order to make it work, can you tell me what is the modification/alteration has been done to the original circuit? Do you change the IC2, pin #3 and pin2 to make it work?
Best Regards
Kamil
about 1 month ago
Hi HL,
It is possible for you to send photo of your project to me?….Do you have PCB layout of the circuit?
kamilnm@gmail.com
Br
Kamil
about 1 month ago
To Kamil. I did not make any mods to the circuit, except that I used TIP2955 & TIP3055 transistors. The pins 2 & 3 on the circuit is probably a misprint and need to be transposed. I cannot send picture as it is fixed in a bird box to disguise it. Just use a piece of strip board with copper strips on one side. All the components except the speaker and transistors were mounted on the board, 24 x 30 holes gives plenty of room. Use sockets for the chips and insert them first [one above the other with about a 6 hole spacing], and build the circuit around them. Flying leads were used to connect the speaker and Transistors and supply. Use coloured leads to save confusion. Layout is not critical. I used the track at one edge for +ve & the oposite track for -ve, placing all other components and wiring somewhere in between. If you are having problems it is a good idea to draw out the circuit as you build it, and compare with the original….in this way you can see if you have missed any connections etc. Hope this is helpful. HL.
about 1 month ago
To Dave regarding squirrels…..Maplin have an electronic gun for sale [9.99] which you point towards the squirrels and pull the trigger. The squirrels disappear quickly….well they did for me!. The gun has 2 switched tones, one of which is audiable, and it looks a little like a small loudhailer. After using for about 4 days no squirrels returned to ravage the plums on my tree. The other option is to feed them with peanuts, and they will leave your berries alone. but I havent seen a squirrel for about 2 weeks now. Worth a try. HL.
about 3 weeks ago
The schematic is basically the same as this one:
http://forum.allaboutcircuits.com/showthread.php?t=26142
What I don’t understand though is why C2 capacitor goes to +V rather than ground.
…Good on you Harry for silencing the damn dog!