Mosquito repellent circuit project

This is mosquito repellent circuit to generates a high sound frequency using transistors as bistable multivibrator. It is economical and safer than using the chemicals.

The mosquitoes are annoying. And, carriers the pathogens to human.  Many ways to protect us from the mosquitoes. Most people use chemicals because the chemicals are high efficiency. But using often chemicals no good for everyone.

Why use Mosquito repellent circuit?
This project uses the sound to mosquito repellents is the safest way for health. Because we generate a high-frequency sound wave that mosquitoes do not like.

According to the theory of scientists found that Mosquitoes do not like the high-frequency sound waves. So, it flies away because this sound interferes with its flying.

How this circuit works

Simple mosquito repellent circuit using transistors, bistable multivibrator

In the circuit, connects two transistors (Q1, Q2) into a bistable multivibrator oscillator to generate a sound frequency. Which the signal of this circuit is determined by both resistors(R2, R3) and both capacitors(C1, C2).

The sound frequencies get out of a collector of Q2. Then, comes into the ceramic piezo buzzer. It emits a high-frequency sound on the radius of under 5 square meters.

If an outdoor using, or mosquitoes disturb too much. You should place this project far from us around 1 meter.

Build Mosquito repellent circuit

The circuit is very easy to make.  As use a few components. To begin with, assemble it with the PCB layout as  Figure 2. It is components layout, should solder them into a right position.

For the value of the circuit should match with the circuit diagram. Then, cut the legs of devices. After that, solder them to connects a 1.5V battery, a switch, and a piezo speaker with the wires.

Characteristics of the piezo speaker is a thin circular metal. One side coated with ceramic in different sizes are 15, 20, 25, 30, 35, 40 and 50 millimeters.
Figure 2 PCB an components layout of this projects.

Testing and application
First of all, check your wiring and circuit for error. Secondly, connect correctly a positive-negative voltage polarity from a common 1.5 volts battery.  Then, turn on S1-switch. We will hear the weak high frequency out of the piezo speaker.  Now, this project is working.

We turn on this circuit for about 30 minutes. Place this near an infestation mosquito. After that, about 30 minutes, the mosquitoes should less. It indicates the circuit works great.

But if the mosquitoes are still too much. Because your circuit may create the frequency, not effect to mosquitoes. Thus, you have to adjust the new frequency by changing the capacitance of C2. From 0.002uF into 0.0022uF or lower 0.0015uF.

Then, observed changing of mosquitoes.

Components list

Resistors ¼ watts + 5%
R1, R4—1.5 K
R2, R3—100 K
C1—560pF 50V polyester
C2—0.002uF 50V polyester
Q1, Q2—2SC9013-NPN type
P1—piezo speaker 35mm.
S1— switch ON-OFF
Battery 1.5V, PCB, Wires, Box, etc.

Other Mosquito repellent circuits

  1. Rat and cockroach repeller circuit
  2. MOSQUITO REPELLANT by IC-555, CD4017, CD4011
  3. Mouse and insects repellent circuit using IC556
  4. Insect repellent device using ic 4047


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