Useful modding  spectrums analyzer + watsh.
 
The general hobby of modding has not bypassed and me. Two lights-emitting diode matrixes 5*8 was completely becoming in a five-inch compartment of a computer - that I had seen decided to make it on basis of spectrums. 
This is idea of the device: the computer program should allocate a spectrum of a sound signal and through a serial port to transfer the data to the microcontroller which in a dynamic mode serves a light-emitting diode matrix. I have looking for information on decomposition of a sound and conclude, to make it with the help of special library for processing a sound bass.dll with distribution what include set of examples in different programming languages of high level.
The microcontroller ATMEL AT90S2313 is the heart of device, if the program to alternate it is possible to use and ATTINY2313. The controllers accepts the data from a serial port and with the help of conclusions of port B and the additional decoder 74145 is deduce a spectrum on the light-emitting diode screen are collected from two matrixes. The unit of the coordination of levels COM - TTL is collected on to transistor. Brightness of a matrix depends from resistors R4-R11.  
The device was collected on two printed-circuit-boards. Two light-emitting diode matrixes were established in the first, and other elements - in the second. The decorative overlay is cut out from an unused plastic of five-inch insert.
 The program of the microcontroller was written in BASCOM-AVR. The managing program from the part of a computer is written on VISUAL BASIC. The program was altered from, example of library for processing a sound bass.dll. Some fragments were added to it. One of its program to be breaks and averages the spectrum in to 16 sites, others to process buttons of management to organize the virtual light-emitting diode screen and to receive data in a serial port. After had earned spectrums analyzer, has added watch in to and casual inclusion - deenergizing of light-emitting diodes. Spectrums analyzer had two operating modes - columns and points. 

http://ledeffects.net/pages/?id=20
