Ambitious 3D spectrum analyzer holds 1280 LEDs

We have seen many LED cube projects that can generate lots of great effects. Sometimes the problem is that in too large cubes inner layers are hardly visible. So what if to build a LED based rectangle with less layers of LEDs. Dooievriend have found great combination of 3D effect and visibility. He has built 16x16x5 rectangle configuration of blue LEDs that displays spectrum of music being played. The heart of this spectrum analyzer is PIC32 microcontroller running at 80MHz. It has enough power to sample sound and calculate DFT of the signal. It samples input signal at 14kHz and then calculates spectrum frequencies from range 20 – 7000Hz. It refreshes the spectrum graph at 80 FPS so it looks really live. Continue reading

A Simple Audio Spectrum Analyzer in a PIC32 Proto Board

Jean Baptiste Joseph Fourier once stated that a composite wave can be represented as the sum of simple sine and cosine waves and this became the basis of the Fast Fourier Transform that is used to chop down waves into its sine and cosine components in order to analyze and identify frequency components of a signal. A hundred years later – Andrei Mehiläinen demonstrated how to use a PIC32 proto board along with a 320×240 PX color LCD to build a simple audio spectrum analyzer. He used a 2048-point FFT (Fast Fourier Transform) algorithm to generate the frequency domain plot. The PIC’s ADC was configured to sample at 48kHz while two potentiometers are used to offset the input signal and to set the voltage reference. Firmware for the project was written using Microchip’s MPLAB C32 compiler. The audio spectrum analyzer can be connected to an unamplified signal source such as your computer’s sound card. Continue reading