Arduino Guitar Pedal
Ian Andal
IME 458
Dr. Pan
Agenda
• Introduction
• How it works:
▫
▫
▫
▫
PCB Schematic
Input Pre-amp Stage
Arduino Digital Signal Processing
Mixer/Output Stage
• Manufacturing Process
• Finished Project
• Results
Introduction
• Goal of this project is to replicate an
Instructables project, the Arduino Guitar Pedal
• The Arduino Guitar Pedal is a low-fidelity (lo-fi),
multi-effects digital guitar pedal with an
Arduino Uno acting as the digital signal
processor
Schematic
PCB Layout
BOM
Input Pre-amp Stage
• The guitar signal goes into the
circuit via J1 connector and
goes to the TL082 IC (U2) at
pin 5 for amplification
• R18 ,R14, and C5 makes the
op-amp act as an active lowpass filter.
• R2 and R9 create a voltage
divider to set the reference
voltage of 4.5V for the noninverting inputs of the opamps.
Arduino Digital Signal Processing
• R23 scales the amplified
guitar signal and that signal
is AC couple to a resistor
divider through C9.
• The resistor divider shifts the
DC level of the guitar signal
to around 0.5V
• The analog-to-digital
converter samples the signal
via A0 pin for signal
processing
Mixer/Output Stage
• The Arduino creates pulsewidth modulated signals that
go through C7 for mixing
• The pulse-width modulated
signals and the clean guitar
signal mix in via the second
op-amp in the TL082 IC (U2)
• This amplified mixed signal
goes out to the guitar amp via
AC coupling through C3 and
the J3 connector.
Design Process
• All through-hole components
• Circuit mainly consists of resistors, capacitors,
and through-hole pads for wires to connect to
• Easier assembly process
Finished Project
Results
• Guitar pedal functioned as expected; played various
programmed guitar effects
• Low quality or lagging in performance for certain
effects due to:
▫ Memory limitations of the Arduino
▫ Bit resolution of the ADC
• Could not fit all the contents into the case due to my
miscalculations on the physical dimensions of the
PCB and the components
Reference
• More information on the Instructable for the
Arduino Guitar Pedal can be found here:
http://www.instructables.com/id/ArduinoGuitar-Pedal/