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The Arduino Audio Meter is a programmable guitar pedal that works with the Arduino UNO board. It is able to read the incoming audio signal and create effects on the four 8x8 LED matrices. The project is Open Source and aimed for hackers, musicians and programmers that want to learn about DSP (digital signal processing), LEDs, guitar effects, and experiment without deep knowledge on electronics or programming.

The project is designed to be fitted in a metal enclosure (Hammond 1590BBS) for better protection. There is a big library of codes available written in standard C that can inspire you. You can also post your creations in the Arduino Audio Meter online forum.

Arduino Audio Meter Specifications:

- Based on Arduino UNO board for signal processing (16MHz, 1KB RAM).
- Analog input/output stages using MCP6002 rail to rail op-amp.
- The original audio signal passes though the pedal without suffering any modification.
- Interface:
- 1 Gain knob (amplifies the guitar signal that goes into the Arduino for better resolution)
- 1 Encoder knob + Push-Button (programmable by the user)
- 4 LED matrix 8x8 (driven by four MAX7219)
- Connectors:
- Input Guitar Jack, 1/4 inch unbalanced mono, Zin=1MΩ.
- Output Guitar Jack, 1/4 inch unbalanced mono, Zout=0.1Ω.
- Power supply:
- Any supply from 9 to 12V. Standard 9V Boss connector works (center tip negative, the pedal needs 600mA).”

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