I am trying to build a LED matrix that can be used as a spectrum analyzer using my laptop mic as input. I already have my arduino code running(the one that controls the 3x3 matrix) and each led gets lit up by receiving a number(0-8) through serial communication with the pc.
I'm having trouble with the actual spectrum analyzer part since I couldn't find any good tutorial on how to make one in Processing and the Minim library documentation is pretty confusing.
I am inclined to think you want the spectrum analyser to run on the PC and just send data to the Arduino to make the lights work - which sounds like a sensible division of functionality. Am I right?
The seven band graphic equalizer IC is a CMOS chip that divides the audio spectrum into seven bands. 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and 16kHz. The seven frequencies are peak detected and multiplexed to the output to provide a DC representation of the amplitude of each band. No external components are needed to select the filter responses. Only an off chip resistor and capacitor are needed to select the on chip clock oscillator frequency. The filter center frequencies track this frequency.
Other than coupling and decoupling capacitors, no other external components are needed. The chip supply can be between 2.7 and 5.5 volts with 5 volts providing the best performance. The device has very low quiescent current (less than 1ma typical) for portable audio devices. the multiplexer is controlled by a reset and a strobe, permitting multiplexer readout with only two pins. The multiplexer readout rate also controls the decay time (10% decay per read), so no external pins are needed for this function.
You can Google for more examples. Color organ projects on Arduino using FFT to process the spectrum. I messed around with a two-channel version (sterio) and the results were very positive.
The project is an Arduino based Bi-color LED Matrix Audio Spectrum Visualizer using the MSGEQ7 IC which is a single channel seven band Graphic Equalizer Display Filter. I have adapted the code from John Boxall at Tronixstuff to display the spectrum to Bi-color LED Matrix displays from jolliFactory.
