This is a real time LED Audio Spectrum Analyzer. You can embed this unit in an audio system or use it as a stand-alone unit.
The LED Spectrum Analyzer can display a real-time bar-graph spectrogram on a 20 x 20 LED display in four different ways.
It produces very nice visual effects and simultaneously provides an effective observable way to inspect audio performance during playback, recording, or any tonal adjustment (bass, treble, mid-frequency adjustment, or adaptive equalization).
The hardware is based on a dsPIC Microcontroller.
Click to send a message to the Author: A.G
For the theory behind this project, please refer to the Digital, real time, Audio Frequency LED Spectrum Analyzer lesson.
Brief History
The first version of this Digital Audio Spectrum Analyzer appeared during 2007 at the "Microchip Embedded Control Design Contest" as the MT1750 project. It was initially published on Circuit Cellar's website. Soon, this project becomes a favourite one among electronic enthusiasts. This is because, it is not just a good project but it also uses a very clever method for digital signal processing and filtering. Later, the project was published on Circuit Cellar Magazine (issue 244, November 2010).
Many individuals across the globe tried to improve the prototype or to build their own version based on an AVR instead of a PIC microcontroller. Nowadays, there are so many versions but the concept behind all is the same: It is the unique digital filtering method, firstly introduced on MT1750.
This method has been further improved by the Author. Nothing changed on hardware, but the latest version of this Audio Spectrum Analyzer uses new concepts not published yet. The latest version has improved dynamic range characteristics and uses additional filtering for best display features.
Technical details
Display: LED Bar-graphs, 20 Bar-graphs, 20 LEDs/ Bar, 400 LEDs / total, RED Monochrome
Bands: 20 bands, 31, 63, 94, 126, 170, 230, 310, 420, 563, 760 Hz, and 1, 1.37, 1.87, 2.55, 3.4, 4.6, 6.15, 8.36, 11.2, 15 KHz.
Resolution: 1.5db
Dynamic range: 30db
Display modes: 4-user selected
Input audio filter: 5th order - flat-top anti-aliasing.
Sampling rate: Oversampling at 80KHz
Input sensitivity: 0-10V, adjustable threw potentiometer
Main Board Power Supply requirements: 5V / 100mA DC
Display Power Supply requirements: 5 - 12V/ 700-1200mA DC
For the theory behind this project, please refer to the Digital, real time, Audio Frequency LED Spectrum Analyzer lesson.
Downloads
Download the Audio Spectrum Analyzer article from Circuit Cellar
Audio Spectrum Analyzer circuit schematics
Audio Spectrum Analyzer latest firmware (machine-code hex file)
Download the Audio Spectrum Analyzer PCB-Artwork and the latest C source-code (paid-downloads)
