This is very easy and good instructable for those who are in trouble for pests.This device will work on any pests those who can sense ultra sonic sound.Basically those who are willing to make any small firm like sunflower,paddy,vegetables,flower ,this is absolutely good for them.In this device we use frequency range for the pests who cant tolerate the ultrasonic sound.
Step 1: Parts List
1.NE555 Timer IC
3.Resistor (R1=150 ohm,R2=100 ohm)
Step 2: Circuit Diagram
In this instructables we use the NE555 IC that can generate both pulse and frequency.This ic is also cost effective.To build this circuit follow the circuit diagram with the specific value.In top i use 150 ohm and 100 ohm and 0.1uF capacitor that can generate 42 khz frequency that can repell the mosquito.But u can also use different value for different pests.
Step 3: Different Frequency for Different Pests
Here some of the frequency range,in which pest can be repelled.Follow this frequency range and replace your resistance and capacitance value.
Step 4: Calculation
Suppose we want to repel mosquito then we can take this values.
The formula for 555 astable mode frequency:
you can change the frequency with this formula.
Step 5: Conclusion
U have to use a 0.01uF capacitor in pin no 5 of 555 timer.
Use 5-15 v to operate the device.Hopefully this will work good in your desired frequency.
Go on !!!