Here are the insects and mice repellent circuit. Many people do not like these animals. We have many ways to expel it away.
This project is safer and more convenient than using chemicals. We just turn the switch on only and use Low power consumption (only 0.5 watts).
It uses a high frequency out of the piezo speaker. And IC-556 is base as oscillator between 22kHz and 56kHz.
How this Circuit works
The working of this circuit is easy. We use IC1-NE556 as main. It has a principle working is similar to IC-555.
IC-555 has a single oscillator only.
But see inside IC-556 has dual oscillator generators. It saves space and comfortable.
In Figure 1 is completely circuit of Mouse and insects repellent projects.
Why we use dual oscillator generators.
Let’s me explain to you.
First, the concept of designer:
The mouse, rat, bug, insects and various animal have the ability to different frequency response in range 22KHZ to 56KHZ.
When we can produce these frequency ranges. Makes we can repel a lot of the type of animals, at the same time.
Second, have ever you use 555 timers? It can produce frequency, right?
Imagine you make an oscillator circuit in one frequency. Then, you change the voltage at a voltage controller pin. It makes the output frequency change too.
Look at the circuit
The IC1/1 will produce a base frequency. They include C1, R1, and R2. We use frequency sawtooth waveform at pin 6 and pin2, is a controls voltage to pin 11. This voltage has value is 1/3 to 2/3 of power supply.
And then the IC1/2 also serves as produce frequencies as same as it. They include C2, R4, and R5. But there are higher frequencies than IC1/1.
When pin 11 voltage changed. It causes IC1/2 to generate changing frequencies from 22kHz and 56kHz.
We connect the output to a piezo speaker. It is the special speaker, that responsible just higher frequencies only.
How to build this project
First search all parts before such as PCB, resistors, capacitors, etc. When finished, then make the as same real PCB layout as Figure 2. Next, to assemble all components as Figure 3.
Figure 2 The PCB layout in real size to use.
Figure 3 The all components layout of this projects.
Should solder lower parts before such as resistors, capacitors, piezo, and other parts in sequence. And do not remember all wires to circuit.
The Soldering, should the soldering iron be used size under 30 watts, and should use a lead combination of 60/40, and Should be careful the heat from the soldering iron to the IC directly. Or should use a socket IC.
The piezo speaker is the specialty type speaker. Which high-frequency response than plain speakers.
If applied with the plain speaker will not get in frequencies as we want, because of it responsible frequencies that the human ear can only hear.
How to testing
When we assemble this project as finished, then enter the power supply to positive supply and ground. The frequency generator will out of the piezo speaker.
Which we can not hear a sound, but when place your index finger touch at pin 8 of IC, then remove the piezoelectric and replace with the plain speaker, cause sound out of the speaker indicate this project work so well.
How to use it
Just only you put this project at a corner or nook in your home kitchen, or use outside the home. To turn into a switch. Next, we have no rats or cockroaches disturbed for a long time. Until battery power is exhausted.
The components list
Resistors ¼ W + 5%
Mylar capacitors 50V
C1: 0.005uF (502) or 5nF 63V MKT
C2: 0.0012uF (122) or 1.2nF 63V MKT
D1: 1N4001 50V 1A Diode
IC1: IC556 dual timer IC with socket DIP 8pin.
And other parts.
Battery 9V, LED, Piezo speaker, etc.
I love electronics. I have learned them by creating the Electronic Circuits and Simple projects to teach my children. Most importantly I hope sharing our experience on this site will be helpful to you.