The effect is a simple fuzz distortion and it can be created with only 5 components.
This is the schematic I used:
Very simple.
One small problem I had was the hum noise coming from the main. And it would get much worse when the led was on. A very simple solution is to place a resistor of roughly 100 ohms from the IN DC vols to ground before connecting it to the circuit. It worked for my project.
Here a couple of pictures:
There are plenty of tutorials and schematics of other effects here and here.
Also, on the instructubles website you will find tutorials in detail on how to build a guitar pedal, from the circuit to the enclosure.
I will build and post more of these in the future.
A video will be posted shortly, as soon as I can get my hands on a decent camera.
