# How to Make a LED Audio Spectrum Analyzer

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## Introduction: How to Make a LED Audio Spectrum Analyzer

LED Audio Spectrum Analyzer generates the beautiful lighting pattern according to the intensity of music.There are lots of DIY LED Music Spectrum kits available in the market, but here we are going to make a LED Audio Spectrum Analyzer using NeoPixel RGB LED Matrix and ARM microcontroller.

You can see this Colorful Music Spectrum in working in the Video below.

In this Instructable, we'll show you the whole working process of the LED Audio Spectrum Analyzer and also provide the complete circuit, PCB and code for the project.

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## Step 2: How to Make a LED SPECTRUM ANALYSER:

1. LED Connection

Connect two 16*16 RGB LED matrixes by connecting DOU interface of the first LED matrix to the DIN interface of the second one, that’s make a bigger 16*32 RGB LED Matrix.

2. Power Connection

The operating voltage of my LED is 5 V, so I would like to connect two LED power interfaces into an outlet of a 5V control power. Please take a note that the maximum current of a working LED is 18 A, so it is recommended to use an over 40 A control power and choose a thick enough wire to connect it.

## Step 3: How to Make a Control Panel:

A control panel is to receive audio signals which are processed by FFT and then transported to be shown by LED matrix display.

The controlled LED is a dot-matrix programmed by WS2812b, whose controlling signal frequency is 800KHZ. And the timing-controlling diagram is shown as above.

Each LED is controlled by 24-bit data with its structure of G7~G0+R7~R0+B7~B0. The data are sent by the principle of higher place first and in accordance with the sequence of GRB.

Constructed by LM358 using an analog circuit, an amplified circuit is displayed by the diagram above.

In the diagram, IN_CH is an audio access terminal of a computer and PC3 is the amplified output signal which has been further sent to STM 32. C13, R6 and R7 are grouped into a signal-strengthening circuit, which can raise the signal voltage and turn a negative voltage into a positive one. The circuit following R8 is signal-amplifying one, with its signal strength of PC 3 equal to R9/R8 times of the previous signal before R8. IN 1+ is the end to set the minimum voltage value output from OUT 1.

## Step 4: LED Audio Spectrum Analyzer Circuit and PCB

Here we use EasyEDA to design the control panel. EasyEDA is a simple and efficient online EDA designing software, by which you can draw a diagram or cut a pattern conveniently.

This link is my competed circuit diagram and PCB, where you can see it very clearly.

You can also register an account there so as to fork my circuit directly into your account.

## Step 5: Prototype Led Spectrum Analyzer PCB

After finish designing PCB, I have ordered some PCBs form EasyEDA. I am pretty happy with the boards I received, and the price was good.They all works well.

If you like it, you can use my PCB order this led spectrum analyzer.

## Step 6: Welding and Connecting

After components are welded the way the following screenshot is shown, a control panel is completed. It’s very simple.

Connect the computer audio cable into the beta version of the welded interface, and then open the computer music. It is possible that you may not hear any sound of the computer music after inserting the audio line. Under such circumstance, we can use a 1-turn-two connector to transform the computer audio output into two channels output. One channel is connected to the core-board while the other to a speaker.

In the diagram shown above, a core-board is powered by a computer USB and connected by an audio output interface. The other interface of the computer audio output is connected to an external speaker. It is feasible when the signal line of the lattice-control interface is connected with the ground wire and the dot- matrix DIN and GND.

Now you just need to upload the below given Program Code into STM32F103RBT6 ARM Microcontroller and you can see the colorful music spectrum.

So here we have built the Audio Spectrum Analyzer with RGB LEDs, hope you like it and you can also change the program to make the music spectrum more splendid.

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## 5 Discussions

Can we use the STM32F103 NUCLEO board to make this project?

Scope for other effects in the code as well.....

Thanks

Subroto

vividz is it posible to change it from 16x32 to 16x64 and if so were in the code would i need to change.

Would this design allow for the ability to make a much bigger display without changes to the circuit board.

Interesting. Although it is hard for me to read this (taken from lcd.h):

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本程序只供学习使用，未经作者许可，不得用于其它任何用途

This procedure is for study only and may not be used for any other purpose without the permission of the author

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Well that is precisely what I'll be using the code for: study it. Maybe I will make something similar to this too. Thanks for sharing!

Of course you can use the code for study, hope you can make it!

Good luck! :)