2 Agenda Introduction How it works: Manufacturing Process PCB SchematicInput Pre-amp StageArduino Digital Signal ProcessingMixer/Output StageManufacturing ProcessFinished ProjectResults
3 IntroductionGoal of this project is to replicate an Instructables project, the Arduino Guitar PedalThe Arduino Guitar Pedal is a low-fidelity (lo-fi), multi-effects digital guitar pedal with an Arduino Uno acting as the digital signal processor
7 Input Pre-amp StageThe guitar signal goes into the circuit via J1 connector and goes to the TL082 IC (U2) at pin 5 for amplificationR18 ,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 0.5VThe analog-to-digital converter samples the signal via A0 pin for signal processing
9 Mixer/Output StageThe Arduino creates pulse- width modulated signals that go through C7 for mixingThe 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 toEasier assembly process
12 ResultsGuitar pedal functioned as expected; played various programmed guitar effectsLow quality or lagging in performance for certain effects due to:Memory limitations of the ArduinoBit resolution of the ADCCould not fit all the contents into the case due to my miscalculations on the physical dimensions of the PCB and the components
13 ReferenceMore information on the Instructable for the Arduino Guitar Pedal can be found here:Guitar-Pedal/