Acoustic Audio Spectrum Analyzer Using AVR

An AVR ATmega8 microcontroller and an operational amplifier is used to build this spectrum analyzer which can improve the audio quality of an equipment.

A variety of displays are supported by the AVR acoustic spectrum analyzer and it uses the EEPROM memory to save the settings. A keyboard can also be fixed in order to change the display effect or its sensitivity as well as the brightness of the display. It can be used with an HD44780 compatible VFD or LCD although it only requires connecting with the audio signal to hear the desired sound. For fast and precise calibration, the audio signal connection can use any programmer.

Behind the display of the analyzer are two PCBs where one is for 8×2 connector displays and one for 16×1. Since there is no PCB for keyboard, the 5 buttons can be used and be connected all to the ground and a small keyboard can be connected to 5-pin connector. The AVR can be programmed with any programmer and the display version code depends on the size to be used. The fuse bits should be set as well as setting the external 16MHz crystal.

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