Wireless Guitar Signal Transmitter
A transmitter and a receiver that transmit wireless the guitar signal and modify it.
Author: Salomia Andrei-Gabriel
GitHub Project Link: link_to_github
Description
This project implements a wireless guitar transmitter based on two Raspberry Pi Pico 2W boards, enabling basic audio transmission over Wi-Fi from a guitar to an amplifier. Additionally, the system applies simple real-time audio effects using software processing: mute, tremolo, and clipping.
Motivation
I am passionate about guitar, and I wanted to see if it is possible to create a basic wireless transmitter using low-cost components. Through this project, I am exploring how can I interact with real-time audio while also making my first steps in the world of embedded systems.
Architecture
-
Transmitter (Pico 1):
- Audio input from electric guitar (6.35 mm jack)
- Signal filtering using capacitors
- Analog-to-Digital Conversion (ADC)
- Apply software audio effects (tremolo, mute, clipping)
- Transmit data via Wi-Fi (UDP)
-
Receiver (Pico 2):
- Receive audio data over Wi-Fi
- Digital-to-Analog Conversion using MCP4725 DAC (I2C)
- Output to amplifier
-
Effect Control:
- 3 buttons to switch between effects
- 3 LEDs indicating the selected effect
System Diagram
Log
Week 28 Apr - 4 May
- Started the documentation for the project, cloned the repository and created the KiCad schematic for the transmitter and receiver, which I'll probably modify later.
Week 12 - 18 May
Week 19 - 25 May
Hardware
| Device | Purpose | Usage |
|---|---|---|
| Raspberry Pi Pico W (2 pcs) | Main microcontrollers | Used for Wi-Fi audio transmission and reception, real-time effect processing |
| MCP4725 DAC Board | Digital-to-Analog Conversion | Converts received digital audio into analog output on the receiver side |
| Breadboard HQ 400p (2 pcs) | Prototyping | Assembles and connects the circuit components temporarily |
| Step-Down Converter MP1584EN (2 pcs) | Voltage regulation | Converts 2x18650 battery voltage down to 3.3V for Pico and peripherals |
| Battery Holders for 2x 18650 (2 pcs) | Power supply | Supplies portable power for the transmitter and receiver |
| Jack 6.35mm Connectors (2 pcs) | Audio interfacing | Used for guitar input and amplifier output |
| Buttons (3 pcs) | User input | Selects between different audio effects (mute, tremolo, clipping) |
| LEDs (3 pcs) | Visual feedback | Indicates the currently selected audio effect |
| Capacitors: | ||
| - 220nF | AC coupling | Removes DC offset from the guitar input |
| - 4.7nF | Signal filtering | Used in low-pass filters for anti-aliasing |
| - 100nF | Power decoupling | Stabilizes the power supply rails for Pico and DAC |
| Jumper wires (set) | Connections | Breadboard wiring between all components |
| Headers 1.27mm (2 pcs) | Pico connection | Allows mounting the Pico onto the breadboard securely |
Schematics
Bill of Materials
| Device | Usage | Price |
|---|---|---|
| Raspberry Pi Pico 2W | Main microcontroller (2 units) | 2 × 39,66 RON = 79,32 RON |
| Breadboard HQ 400 Points | Prototyping (2 units) | 2 × 4,56 RON = 9,12 RON |
| Suport de Baterii 2x18650 | Power supply (2 units) | 2 × 3,99 RON = 7,98 RON |
| Modul DC-DC Step-Down MP1584EN | Voltage regulation (2 units) | 2 × 6,49 RON = 12,98 RON |
| Kit Rezistoare 250 buc Plusivo | Biasing, Filters | 14,99 RON |
| Set Fire Mama-Tata pentru Breadboard | Connections | 7.99 RON |
| Header Pini 1.27mm 40p | Mounting Pico on breadboard | (2 pcs) 2.56 RON |
| Buton 6x6x6 | User input | (2 sets of 3) 0.72 RON |
| [LED-uri 5mm și 3mm roșu/verde/galben] | Visual feedback | (12 pcs) 4.68 RON |
| MCP4725 Breakout DAC Board | Digital-to-Analog conversion | 38,86 RON |
| Condensator MC5-220N (220nF, Poliester) | AC coupling (audio input) | (4 pcs) 5,77 RON |
| Jack Audio 6.35mm ACJM-IH | Guitar input and amplifier output | (2 pcs) 15,24 RON |
| Condensator FG28C0G1H472JNT06 (4.7nF, ceramic C0G) | Low-pass filter | (10 pcs) 5,92 RON |
| Condensator K104K10X7RF5UL2 (100nF, ceramic X7R) | Power decoupling | (3 pcs) 2,89 RON |
Software
Links
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