Hgmjr, Sir in the circuit Ultrasonic Pest repeller can i use 555 ic as a square wave oscllator which is less expensive than using CA3130? Is there a reason why CA3130 was used instead of 555?

 

That thread you posted in was years old - http://forum.allaboutcircuits.com/showthread.php?t=1955

The frequency is in the range of a 555. That CA3130 is an obsolete op amp design that has no internal compensation.

 

can i use 555 ic as a square wave oscllator

That's what I'd use. Look up any astable 555 circuit and choose values for the desired frequency. A 555 can also source plenty of power to drive a speaker or transducer directly or, if you're trying to rid the entire neighborhood of bugs, rats and mice (with the drawback of driving all the dogs and cats crazy) you can easily use the output of a 555 to drive a single transistor power stage.

Problem here is after all these years there is still only questionable data that ultrasonics actually repel much of anything, that's why I laugh when I see the ones advertised that plug into a wall socket and chase the roaches out of your walls by turning all your house wiring into rays of death.

 

Look at Pest Repeller in Google. Many articles say that high frequency noises do not repel pests.

 

http://www.electronic-circuits-diagrams.com/audioimages/6.gif
This is the circuit im talking about. The oscillator that triggers CD4017 is an op-amp CA3130. Why did the author of the circuit choose CA3130 instead of 555 which is less expensive?

 

I am presently using an ultrasonic pest repeller from Taiwan that automatically changes frequency to cover rats, mosquito, mice and cockroach. First few days i noticed the increased activities of rats, mice and cockroach during day time. I supposed they are irritated by the ultrasonic sound. Then after a week the i noticed that i cant get anymore mouse in my four mouse traps. Before i can get 4 mouse in my trap per night but since using the ultrasonic repeller the traps are empty for 2 weeks now.
The technique here is to turn off the ultrasonic pest repeller every now and then so that this pest will not get used to it. It also works fine with repelling mosquitoes.
The IC used is TK98P01 (Taiwan made) which is not available in my country so I prefer to use this circuit
http://www.electronic-circuits-diagrams.com/audioimages/6.gif
which also changes frequency automatically.

 

The circuit uses parts that were common 45 years ago.
Nearly all circuits from that Indian website are very old and most of the circuits do not work.

 

Raccoons, just need them to move out until I get a change to clean and seal up the space.

Two old fire strobes, junk CAT5 cable, alligator clips, a fuse, two almost dead car batteries for 24vdc and hoping the next door neighbors stay on vacation and the the pests find a nice new home somewhere else.

 

Looks like they moved out for now, so it's time to run the flashers down the back supports facing forward under the tool shed after spraying some hot sauce mixed with liquid soap to make their beds a little warm.

A shed construction pic:

Music with a nice comfy chair is the only way to work.