The easiest and cheapest way to make an oscillator is using the famous 555 timer chip, which in Indonesia it cost roughly about Rp. 800,-. It’s a simple oscillator which produced a square wave signals. You can also call it as “Poor man’s oscillator” :P. Even as simple as it is, or as cheap as it is, this oscillator is still a powerful instrument. I build this oscillator based on “Laser Ray” Schematic from “50 555 Circuits” E-book by Collin Mitchel. I also made the EagleCAD schematic and board file bellow.