Design and implementation of mixed light effect based on the audio signal frequency spectrum analysis

Spectrum analysis can quickly extract signal features, and is widely used in digital signal processing (DSP). Fast Fourier Transform (FFT) is chosen in the application for audio signal frequency spectrum analysis. The paper is based on FFT, aiming at audio signal acquisition, do optimization of the reverse position and butterfly algorithm, and then utilize the optimized algorithm to do frequency spectrum analysis about the audio signal in different formats, then realize the dynamic effect of mixed colors of lights. In the concrete realization of the system, through the micro controller STC12C5A60S2 to read a variety of digital music signal in SD card or U disk and other physical media by using the SPI protocol, then use the audio decoder VS1003 to covert digital signal to analog signal for playing. when playing music, use the A/D converter to do analog signal acquisition, then use the optimized FFT algorithm to analyses and extract the features, then through the micro controller and PWM technology to produce different duty ratio of the pulse signal, and then drive LED in a variety of color to realize dynamic mixed light.