“This is a simple square-wave generator that basically uses the TimerOne library allow you to generate a PWM signal at pin 9 in the range from about 5Hz to 1 Mhz, and you can adjust the duty cycle from 0 to 100%.
Device is very simple to build and consist only a few components:
- Arduino nano microcontroller
- LCD Display
- Three pull Up resistors
- and three push buttons
The pulse generator has the ability to adjust the pulse repetition period using the buttons connected to digital inputs 6 and 7 of the Arduino. 13 input pin allows you to adjust the duty cycle.”