This project aimed to design a multi-effect guitar pedal with a focus on vintage sounds, circuit theory, hardware simulation, and embedded system design as a part of our senior project. We sought to blend our passions of guitar playing, music, and electrical engineering into a device someone without our background could make use of.

Most guitar pedals only contain one effect. Examples include Fuzz, Reverb, Echo, Compressors...

These pedals all accomplish unique sounds but can get both expensive and unruly in regards to cable management. There are entire subreddits dedicated to pedal theory and the optimal placement of each effect in a pedal chain. One thing that is generally agreed upon is that if you use both wah and distortion they are best placed wah then distortion.  Establishing that as our rule leads to the inclination of combining the two effects into one multi-purpose unit. So we did.

We used Multisim for creating the initial schematics and used Simulink for audio testing. In tandem the two programs allowed us to verify circuit functionality and listen to the effects before any physical implementation was created. We then took our designs to Breadboards and fixed some things. Then soldered them on Veroboards and fixed some more things before finally encapsulating them in a wooden housing complete with a functional foot-actuated linkage mechanism that turns the Wah pot. We are not mechanical engineers and it was the hardest part by far. Don't try to make your own Wah pedal unless you own a manufacturing facility.

Features and Highlights:

• Fully analog circuit design

  • Preserves sound resolution by avoiding analog-to-digital conversion

  • 0 microcontrollers

• Multisim circuit simulations

  • Designed individual effect stages and integrated them into one circuit

  • Able to simulate wah frequency response and visualize the change of signal shape when distortion is enabled

• Simulink audio simulations

  • Recorded clean guitar audio and saved as .wav

  • Input .wav through Simulink and Simscape Electrical to simulate the circuit’s effect and sound

  • MATLAB Audio Processing Toolbox used to save output audio files and analyze frequency response

• Custom Housing (She ain't pretty)

• Hand-soldered Active Filter and Distortion clipping diodes (They sound like it)