A programmable guitar effects shield for Arduino MEGA, featuring OLED display, true-bypass footswitch, and DSP-ready input/output stages. Based on pedalSHIELD MEGA by ElectroSmash
- ✅ KiCad project: schematic & PCB layout files for the hardware shield
- ✅ Arduino examples: boost, fuzz, delay, and other DSP sketches
- ✅ Bill of Materials: CSV file with component list and Mouser links
- ✅ Documentation: assembly guide, schematic diagrams, signal flow
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Clone the repository:
git clone https://github.com/nablum/pedalSHIELD-MEGA.git cd pedalSHIELD-MEGA -
Build the PCB with KiCad or order the board from a fab using the provided Gerbers.
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Solder the components according to the Assembly Guide.
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Upload an effect sketch to your Arduino MEGA using Arduino IDE.
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Plug and play:
- Guitar IN → Input Jack
- Output → Amp or Audio Interface
- Power → USB or DC JACK.
Each audio effect is implemented in a separate folder under firmware/effects/:
| Effect Name | Description |
|---|---|
| BitCrusher | Reduces resolution and sample rate for lo-fi textures |
| Chorus | Modulates pitch with delay to create a thickening effect |
| ChorusOrVibrato | Blendable chorus and vibrato with adjustable depth |
| Clean | Transparent clean boost (reference circuit) |
| Distortion | Hard-clipping distortion effect |
| Echo | Simple digital delay with feedback loop |
| Fuzz | Saturated high-gain fuzz effect |
| MultiEffects | Combination of multiple effects in a single patch |
| OctaveCrusher | Bit reduction with added octave-up/down harmonics |
| Octaver | Mixes original with octave-down processed signal |
| Reverb | Simulates ambient reverb using delay-based algorithm |
| Tremolo | Volume modulation using a low-frequency oscillator |
| Vibrato | Pitch modulation effect for expressive shimmer |
- Compatible with Arduino MEGA 2560
- 128×64 I²C OLED display (SSD1306)
- True-bypass footswitch with relay
- Stereo audio jacks with analog preamp/output
- Powered via 12 V DC (center-negative)
- OLED not lighting up → Double-check I²C wiring and 4.7k pull-up resistors.
- No audio output → Ensure signal chain is complete and shield is powered.
- Arduino upload fails → Check USB port, board selection, and serial permissions.
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🔬 pedalSHIELD-MEGA Documentation – ElectroSmash
Official guide, schematics, theory of operation, and signal path details. -
🧰 Assembly Guide – PDF
Step-by-step instructions with images for building the pedalSHIELD‑MEGA hardware. -
📦 u8glib – OLED Display Library
Arduino graphics library used to drive the OLED screen (SSD1306, I²C). -
💻 Arduino IDE Downloads
Install the Arduino IDE to compile and upload code to the MEGA 2560.
Contributions are welcome! You can:
- Submit new audio effects or improvements to existing sketches.
- Suggest hardware upgrades (e.g. better op-amps, analog filtering).
- Improve documentation or add new troubleshooting tips.
Please open a pull request against the main branch and follow the coding style of existing files.
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Hardware (PCB files, schematics, BOM):
Licensed under Creative Commons Attribution-NonCommercial 3.0 (CC BY-NC 3.0) -
Software (Arduino code, examples):
Licensed under the MIT License
Created by @nablum.
For questions or collaboration ideas, feel free to open an issue or reach out directly.