As part of a series of up-and-coming BuildBrighton workshops, and in preparation for this year’s Mini Maker Faire we’re busy putting together some simple effects “pedals” that can be put together inside a guitar, to provide onboard electronics.

We’ve already started work on a number of fuzz-face (distortion pedal) variants.
This time it’s the original Cry-Baby Wah effect that we’re looking to emulate. In fact, this circuit design is quite a bit simpler than the Dunlop version, but is perfect for what we’re trying to acheive – a simple, workable circuit to act as an introduction to gutiar electronics. Here’s the circuit schematic:
And the PCB layout:
Wah Pedal PCB
(as ever, print onto A4 at 100% no scaling for a press-n-peel/toner-transfer-ready image for etching your own)

This is how the final PCB should be assembled:

The beauty of this simple design is that it uses a single 500K linear potentiometer to achieve the wah-wah sound. Which means we can do a lot with this design when it comes to “hacking” up our guitars later. For example, it could be replaced with a digital pot and hooked up to a microcontroller (such as a PIC or Arduino) for all kinds of funky fun!