This project is very special and powerful pest repeller which produces ultrasonic waves.  In presence of these waves the rats, insects and pest set. run away.  It is injuries for the health to use the insects killing durgs.  Thus this project is harmless for human beings.  This project is boom to keep away the mosquitoes and insects produced in the rainy season.



This project you can use in your house, shop and godown.  IC CD4047 is used in this circuit which produces ultrasonic waves.  This IC gives complementary output.  There are total 14 pins in two lines.  The positive supply is given to pin no. 4, 5, 6 & 14.  Its pin no. 7,8,9 & 12 are grounded.  VR [100K] is connected in between pin no. 2,3 which is used to adjust the frequency for better response.  The complementary outputs from pin no. 10 & 11 are given to the bases of Q3 and Q4 [BD139/BD230] directly for amplification through resistance R1 and R2 [1K2].  The amplified signal from the collector of these transistor is given to the outer terminals of primary of the transformor.  The boost ultrasonic signal from the secondary due to mutual inductance is given to the tweeter.  Ferrite is used in this transformor.  In the primary coil of the transformor 152 turns of 28SWG insulated copper wire are wound.  In the secondary coil 42 turns of 24 SWF copper wire are wound.

This project should be hang at the hight of two feet from the ground keeping the direction of tweeter or speaker towards the floor  Due to this the ultrasonic waves from the tweeter will get reflected from the floor.  These waves are not easily reflected from wood are paper board.


NOTE:- The 9V supply in the circuit is given through dry cells.



  1. Use IC base for the IC.
  2. Take care that there is no shorting on PCB while soldering the components.
  3. First of all, check all the components so that they are OK as per the circuit.
  4. Solder carefully collector, base and emittor terminals of the transistor.
  5. Clean all the terminals of the components before soldering.