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 8x8 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.
– 8x8 LEDs Matrices and Drivers: Four “common anode” matrices are used creating a 16x16 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 8x8 (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).