ELECTRONIC MOSQUITO REPELLER

General Description

This simple circuit can prove itself worth many times its value

in getting rid of mosquitoes without having to use potentially harmful chemical

repellents. It is a simple multivibrator which oscillates at a frequency of approximately 5 KHz.

It uses a common piezoelectric microphone as a transducer and runs off a small 1.5 V

battery, which because of the very low consumption of the device, will last very long even with

continuous use.

Technical Specifications - Characteristics

Working voltage: 1,5V DC

Max. current: 1 mA

Working frequency: 5KHz

How it Works

The principle upon which this little device is based is very simple really. It is well known that

only female mosquitoes bite. Research has proven that the sound produced by male

mosquitoes makes females go away (except when they are in the mating period of course).

This sound is what the little device produces and thus it keeps mosquitoes away. As

seen from the circuit diagram the circuit is a simple multivibrator built around two

transistors. The frequency of oscillation is determined by the two capacitors C1 -C2 and the

resistors R2 -R3. The output is taken from the collectors of the transistors and is used to drive

a small piezoelectric element (a small crystal microphone in fact) which produces a barely

audible but nevertheless effective 5 KHz tone.

Electronic diagram

It can be powered by AC power system; it can give out a special ultrasonic wave and its effective area

can be cover around 16 sqm

The common Mosquito Repellents available in the market can be powered By 4 pcs of AAA dry batteries,

A common variety is the frequency-changing Bionic Mosquito Repellent which is portable and can give out two kinds of

simulation sounds----wings vibration of the male mosquito and dragonfly (natural enemy of mosquito)

which can drive the fragrant female mosquito away. According to biology and bionics, only the fragrant female mosquito

can bite and they will avoid the male mosquito from approaching. The effective area can be covered around 9 sqm.

An AC Operated Mosquito Repeller with LED Light Emits dual sonic frequencies to irritate and drive mosquito away.

It is non-toxic and no chemical usage or disposals. It is safe for use. Automatic Mosquito Repeller with LED Light

has two functions : Night Light and Mosquito Repeller

The features include:

Automatically on at dusk, off at dawn with ultra bright LED

100-120V or 220-240V, 1W

Effective range up to 5m

Ultrasonic scan output up to 120dB/m

Up to 30 square meter protection

Size (Euro Type): 82x115x80mm (WxHxD)

Available with European, Italian, Australian, US and Japanese Plug

Some of the features of a portable wrist-strap repeller also available in market can be detailed below :

Completely portable - with "Built-In" strap for wrist and ankle placement and "Clip-on" attachment for belts and pockets

Effectively covers an area up to 6 to 8 square feet

3 level switch:

o 0=OFF

o I=Male Mosquito (silent)

o II=Dragon Fly (very slight sound)

Red LED nighttime assitance light

Some other varieties which are available in the markets may look like this: