DSP Lo-Fi Guitar Sampler

A University Project Exploring Real-Time Audio Processing for Guitarists

Hi,

My name is Fotis Stamatakis and i am currently studying Electrical and Computer Engineering at the University of Peloponnese in Patras, Greece working on a DSP / lo-fi audio sampler designed specifically for electric guitar. This project combines embedded systems, real-time signal processing, and custom PCB design , exploring how modern hardware can be used to build expressive, hands-on musical tools.

The device is built from the ground up and designed to run completely standalone, thanks to a custom PCB that integrates everything needed for sampling, playback, recording , effects, and audio output .

This sampler is a creative audio tool that lets guitarists:

• Record play and loop guitar samples
• Apply real-time DSP effects like bit crushing, pitch shifting, and frequency shifting and simulate common pedal functions
• Visualize sound with a 0.91" OLED screen
• Save and load samples via SD card
• Operate using just a USB-C port (low power design)
• And for extra versatility drive external speaker

PCB OVERVIEW:

This 4-layer PCB includes:

• STM32 microcontroller (STM32F405RGT6)
• TLV320AIC3104 audio codec
• TLV9162 op-amps used as unity gain buffers to ensure suitable impedance for the guitar
• SSD1306 OLED display
• MicroSD card slot
• USB-C power input and data lines for virtual COM ports or data transferring
• 3.3V switching regulator and 3.3VA ,1.8V LDOs
• Class D amplifier (15W speaker from a separate 15V supply)
• Serial Wire Debug Headers for an easy debugging experience
• Interfacing buttons and potentiometers(headers) that can be used as the user wishes
• Indication LEDs focused around the 4 main functions of a sampler ( PLAY ,STOP, RECORD, LOOP ).
• A significant amount of filters ensuring optimal operation and listening experience

This project is more than just a class assignment it’s a self-directed learning journey that brings together everything I’ve studied:

digital signal processing, embedded programming, mixed-signal PCB design, real-time audio processing, and power systems.

It’s also a way for me to explore creative audio design and share something useful with other musicians and makers.

I’m asking for PCBWay’s support to help fabricate and assemble the first version of the PCB. As a solo student with a limited budget, this sponsorship would allow me to move from design to a working device and focus on testing, firmware, and sharing the project with the community.

Thank you for considering it !!!