A frequency generator is a very handy device in electronic design, development, testing and trouble shooting. It is such a kind of device which can generate the required frequencies which can be then applied directly to the target device for testing it. There are frequency generators which can generate the required waveform like sine wave, saw tooth wave etc. but for normal applications the square wave generation with variable frequency is sufficient.This particular project explains how to make a variable frequency generator with the help of Arduino.The Arduino is referred to as an easy prototyping platform which has been popular among both hobbyist and experts and widely used in industries as well. Any AVR microcontroller based board which follows the standard Arduino schematic and is flashed with the Arduino bootloader can be called an Arduino board.