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Home made Graphic Equalizer Answered

I'm trying to make a Graphic Equalizer to go on my wall and will move to the output sound on my Computer, i have soldered all the LED's, but i'm having issues with the main board!?! i'm not fully sure how to make at and what i will need, plus i can't find the coding anywhere for the mircochips.

Please Help,

I will be posting a step by step guide once finished and tested.




um im not sure you are using the words "graphic equalizer " correctly i think you mean led vu meter (lights that move with the sound of the input source) (a graphic eq is for adjusting the volume of different audio frenquency bands) hope this helps

lol 2 years old, im wondering, have you completed this project?

Hi weeby-vuit!

I was just wondering if you have had any headway on this project.

If you've managed to work it out, a step by step would be amazing!


hey Weeby-Vuit, did you ever get the first board working, because I'd like to attempt the same project, can you help me out with it?

I'm afraid not Adam, i have recently moved jobs and house, Don't worry i will be continuing with it and i'll keep you posted.

Your other option is a crazy transistor based circuit but for 8 levels and ten Leds each you'd be talking 80 transistors

sorry 160 transistors, 20 leds a go... Maybe some kind of diode clipping could be used...


10 years ago

I believe you need any of the following:
1.Fast Fourier Transform (yucky advanced calculus)
FFT is often implemented in DSP chips. ***
2.Many audio filters, the ones controlled by an equalizer's knobs,
each connected to any kind of LED bar graph circuit.
3.Fake it with just one bar graph circuit connected to several
columns of LEDs, leaving out some volume levels in some bars.

***If you think you are up to the challenge of method 1,
here is documented code of an FFT on a Microchip PIC chip:

Viron, I think I have the Audio filters for number 2, and I think that was the one I was going to design, but do you know anywhere where I can find a circuit diagram and programming code for it???

Number 2 does not have any programming, it's analog.
(in Number 3 i gave a link to an example of a FFT program.)
I'd use the filters from an equalizer, as they are very mathy to
design and consist of lots of resistors and capacitors.
google led vu meter schematic

google twin t bandpass filter
You need a different frequency filter for each LED meter.

oops, the code link is not for #3(the fake method), it's for #1. And that code, the FFT, is almost equivalent to several digital bandpass filters with volume level outputs. FFT is how all MP3 player graphic equalizer visualizations work.

How many LEDs did you use, and did you multiplex them? What are you going to use for a uC? AVR or PIC?

it is using 20 Red and 20 Orange Spuerflux LED's for each bar and there are 8 bars to one board, I intend to have about 8-10 boards in total, but need to get the first one working.