The ElectroSmash website has featured a new Arduino Audio Meter which takes the form of a programmable guitar pedal based on the Arduino UNO development board. Providing users with the ability to read the incoming audio signal and create effects on the four 8×8 LED matrices. check out the video below to learn more
Features of the ElectroSmash open source programmable guitar pedal include:
– Analog Input Stage: The weak audio input signal is amplified and filtered, preparing it for the Arduino UNO ADC (Analog to Digital Converter). A rail-to-rail operational amplifier is used (MCP6002) to amplify the signal (2 to 30 times depending on the Gain potentiomenter) so any audio input signal could be used.
– 8×8 LEDs Matrices and Drivers: Four “common anode” matrices are used creating a 16×16 display. Four MAX7219 chips are used to drive the matrices. The communication between Arduino UNO and the LEDs is made using 3 lines DIN (Data IN), CLK (clock) and Load. The standard Led Arduino Library (LedControl.h) is used in most of the examples.
– Power Supply: Using four 8X8 LED matrices makes a total of 4x8x8=256 LEDs, because of that the current could rise up to 500mA (Vin=9 to 12V). This is why we use a VXO7805-1000 (capable of 1A max. output current). A more standard 7805 could also be used but it gets hot.
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.
– 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 8×8 (driven by four MAX7219)
– Input Guitar Jack, 1/4 inch unbalanced mono, Zin=1MΩ.
– Output Guitar Jack, 1/4 inch unbalanced mono, Zout=0.1Ω.
– Any supply from 9 to 12V. Standard 9V Boss connector works (center tip negative, the pedal needs 600mA).