This document describes a simple electronic mosquito repellent circuit that uses a 555 timer IC to generate ultrasound frequencies between 20-38 kHz, which repel mosquitoes but are inaudible to humans. It explains that mosquitoes can detect these ultrasound frequencies through sensory structures in their antennae. The circuit works by configuring the 555 timer in astable multivibrator mode to generate a 25 kHz frequency, which is then converted to ultrasound by a piezo buzzer. This ultrasound irritates and repels mosquitoes without disturbing humans.

1. MOSQUITO REPELLENT
USING 555 TIMER IC

2. MOSQUITO
Mosquitoes are small, midge-like flies which comprise the family Culicidae
Mosquitoes are known to carry many infectious diseases
from several different classes of microorganisms, including
viruses and parasites. Mosquito-borne illnesses include
malaria, West Nile virus, elephantiasis, dengue fever,
yellow fever etc. These infections are normally rare to
certain geographic areas

3. How to prevent mosquito bites

4. WHY ELECTONIC MOSQUITO REPELLENT?
• Mosquito repellents like coils, mats, liquid vaporizers, 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 vaporizers 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.

5. How it works-
• 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 antennae. 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.
• In other words, a simple circuit is designed which can produce ultrasound in
the frequency range of 20 kHz to 38 kHz, which can scare away mosquitoes.

6. Circuit Description

7. •Here the 555 timer is configured in astable multivibrator mode,
specifically devised for generating sound at the ultra frequency levels.
•The frequency of this circuit is set to 25 kHz, this frequency falls in the
ultrasound region and it is not audible to human beings.
•The 1N4007 diode is used to get 50% duty cycle for the frequency
generator.
•The piezo buzzer converts the output of 555 astable to ultrasonic sound
that can be heard by the insects.
•This ultrasound frequency cause some irritations and uneasiness to the
insects such as mosquitoes. However it will not disturb you if you have
installed this circuit of insect repellent for your home.

8. THANK YOU!!