METHODOLOGY

For this project, we have chosen a circuit found from a reliable source at internet which we have modified it ourselves to be more completed with variable frequencies generated and controlled.

Electronic Animal and Insect Repellent Circuit Diagram

In order to be able to use normal 9V battery for the purpose of domestic usage of this project, we have modified the circuit by added a power supply circuit part to convert the voltage input of 9V to 5V.

The 4 main components beside 555 Timer we have chosen to use are resistor, preset resistor, variable resistor and speaker. Resistors are the most common electronic components used in any electronic circuits, electronic devices and electronic projects. Resistor limits the function of voltage across or through it. It also serves as the simplest voltage divider.

Preset resistors are used in circuits when it is necessary to alter the resistance. Dark/light and temperature sensors usually have these components as the preset resistor allows the circuit to be made more or less sensitive (they can be turned up or down - reducing or increasing resistance).

The variable resistor is a resistor with a resistance value that can be adjusted either mechanically by means of a revolving or sliding. It is also often referred to as VR. It has a resistance value which varies as choosing a fixed resistor. The types of VR are the type of potentiometer or preset.

Speaker uses a coil of wire, which acts as an electromagnet, set inside of a magnetic gap of a permanent magnet. The speaker converts the electronic frequency to sound frequency. Try to keep the frequency of the sound as high as possible. So that the annoying sound will be heard by insects only but not human because humans don’t normally hear sound of frequency higher than 20 KHz.

As for the design method, we used analysis software of Livewire to stimulate, modify and construct the schematic circuit. The purpose of using Livewire as it is easier to construct and easier to understand. Besides, it can be fully examine the relationship between the resistance and the frequency generated by the 555 Timer. Then, we test run the hardware several time by connected the circuit in a breadboard before iron soldered into a circuit board in order to complete the prototype.

The following flowchart is the process of production of Electronic Animal and Pet Repellent project from the beginning until the final production.