1. Arduino Guitar Pedal
Ian Andal
IME 458
Dr. Pan

2. Agenda Introduction How it works: Manufacturing Process
PCB Schematic
Input Pre-amp Stage
Arduino Digital Signal Processing
Mixer/Output Stage
Manufacturing Process
Finished Project
Results

3. 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

4. Schematic

5. PCB Layout

6. BOM

7. 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 low- pass filter.
R2 and R9 create a voltage divider to set the reference voltage of 4.5V for the non- inverting inputs of the op- amps.

8. 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

9. Mixer/Output Stage
The Arduino creates pulse- width 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.

10. Design Process All through-hole components
Circuit mainly consists of resistors, capacitors, and through-hole pads for wires to connect to
Easier assembly process

11. Finished Project

12. 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

13. Reference
More information on the Instructable for the Arduino Guitar Pedal can be found here:
Guitar-Pedal/