Electronic Mosquito Repellent Circuit

Mosquito repellents like coils, mats, liquid vaporisers, creams are often used at various places. However they are prone to be fatal and can cause harm to human beings. For instance, mosquito repellent creams and oils can cause adverse affects on the skin like allergic reactions. Coils, mats can produce toxic fumes when heated and cause breathing trouble, whereas liquid vaporisers can also produce fumes when heated.

For efficient results without any side effects, the most optimum solution is building a simple electronic circuit with minimal components which can produce output so as to repel the mosquitoes. In plain words, this article is going to describe a simple mosquito repellent circuit.

Principle Behind Mosquito Repellent Circuit:

Human beings can hear sound in the range of 20 Hz to 20 kHz. Sound of any frequency above 20 kHz is termed as ultrasonic sound. Several animals like cats, dogs, insects, mosquitoes have the feature of being able to hear this ultrasonic sound. In mosquitoes, this feature is attributed to the presence of sensory structures in their antenna.

Usually ultrasound is transmitted by male mosquitoes and received by female mosquitoes. However after breeding, female mosquitoes generally avoid the ultrasound and this fact can be used to produce ultrasound in a range similar to that produced by male mosquitoes and repel away the mosquitoes.  The ultrasound produces a stress on the antennae of the mosquitoes and repels them away

Circuit Diagram of Electronic Mosquito Repellent Circuit:

Theory Behind the Circuit:

• A multivibrator is an electronic circuit producing a pulsed output signal. Generally multivibrators are classified based on the nature of stability of output.
• A multivibrator with one stable state is known as monostable multivibrator and is used as a pulse generator.
•  A multivibrator with no stable state is known as an astable multivibrator and is used as an oscillator.
• A multivibrator with two stable states is known as a bistable multivibrator and is used as a Schmitt Trigger.

Here we are mainly concerned about Astable multivibrator. Astable multivibrators do not require any external triggering and hence can be used as oscillators. They are realized using transistors, operational amplifiers or ICs.

Applications of Mosquito Repellent Circuit:

As described, this circuit can be used as a mosquito repellent. By certain modifications and changes in the value of resistors and capacitor, the circuit can also be used as other insect repellent. Further, it can also be used as a simple buzzer alarm circuit.

Mosquito Repellent Circuit Limitations

• It requires a lot of frequency setting.
• Ultrasound signals travel at an angle of 45 degrees from the source. In case of any obstacles in the path, the signals get reflected or diverted.
• It shows effect for lesser mosquito population.