Arduino Based Mini Audio Spectrum Visualizer

Introduction

For our last project, we built a 3D Stereo Audio Spectrum Visualizer. We are delighted that it attracted quite a bit of interest with suggestions on how we could have built the display differently. Some argued that it is not a true 3D audio spectrum visualizer and we totally agree with them. We should have titled that project more appropriately. If you are interested, you may check out the project here.

Following that last project, we have made the stereo audio spectrum visualizer board into a basic DIY kit which is now available at jolliFactory's Tindie store.

This audio spectrum visualizer kit is also suitable for use in our other Arduino based Bi-color LED Matrix Audio Spectrum Visualizer project.

These two audio spectrum visualizer projects use SPI for connections to the more elaborate bi-color LED Matrix and 3D LED Matrix displays for visualization. For this instructable, we will be building yet another audio spectrum visualizer but we will be using a 0.96 inch 128x64 I2C OLED graphic display instead. This is quite a tiny display but that is all we have lying around. You may want to use a larger screen OLED display for your project. This is a much simpler project if you just like to experiment with audio spectrum visualizers and do not want to spend too much time and money on the display.

You may find the 0.96 inch I2C OLED display from Adafruit or as an add-on module with our JF Stereo Audio Spectrum Visualizer DIY kit.

You may view the following YouTube video to see what we are building.

 

Step 1: Building the Audio Spectrum Visualizer Board

You may wire up the audio spectrum visualizer board using perf-board yourself according to the wiring diagram above. We will not go into detail on how to wire them up here.

For this project, to save time from having to wire up the circuit, we will be using the JF Stereo Audio Spectrum Visualizer kit set available on Tindie. For this project, we assume you have some basic electronics and soldering skills and is familiar with using the Arduino board. The kit set is quite simple to complete. So, we will not be going into the detail on assembling the JF Stereo Audio Spectrum Visualizer board here.You will need to ensure the MSGEQ7 ICs and the Arduino Nano are placed in the correct orientation.

Our audio spectrum visualizer shall be driven by an Arduino Nano. We will basically be using two MSGEQ7 IC chips made by Mixed Signal Integration to separate the audio into bands. The MSGEQ7 IC is a single channel seven band Graphic Equalizer Display Filter. By feeding an audio signal to it, it will filter out seven frequency bands centered around 63Hz, 160Hz, 400Hz, 1,000Hz, 2,500Hz, 6,250Hz, and 16,000Hz. The seven frequencies are peak detected and multiplexed to the output to provide a DC representation of the amplitude of each band. All we need is to read these DC values with the microcontroller analog input and output the spectrum to the OLed display. We need two MSGEQ7 ICs here, one for the left and another for the right audio channel. 

 

Step 2: Wiring Connections

The main objective of this project is for experimentation on audio spectrum visualization. To keep it as simple as possible, we will be using an off-the-shelf mini 0.96 inch I2C OLED graphic display instead of building elaborate displays. This display requires only 2 signal lines and 5V DC for power. See the photos above on how the I2C OLED is connected to the JF Audio Spectrum Visualizer board.

The I2C OLED display is available at Adafruit or as an add-on part if you purchase the JF Stereo Audio Spectrum Visualizer kit which will be made available soon.

We have also connected a momentary push button switch to SW1 on the PCB board which is connected to D8 and GND of the Arduino board. This switch shall be used for selection of different display effects.

 

Step 3: Programming the Arduino Board

The Arduino board needs to be loaded with the Arduino sketch to drive the Audio Spectrum Visualizer.

Download jolliFactory_I2C_OLED_AudioSpectrumVisualizer.ino

You will need to install the support library for the OLED graphics display which is available for download below.

Download Adafruit SSD1306 Library
You will also need to install the Adafruit GFX library.

Download Adafruit GFX Library

You may need to change the I2C device address in the sketch for it to work with your OLED display. Our OLED display is using I2C address 0x3C by default.

If you are not sure what is your I2C device address, you can download an Arduino I2C scanner sketch to determine the address. Check out I2C Scanner page at Arduino playground for more information.

We have only designed three effects for the audio spectrum visualizer. Let your creative juice flow and enhance the program with more interesting effects.

 

Step 4: Testing the Audio Spectrum Visualizer

We will not delve into the details on how to test if our audio spectrum visualizer is performing correctly here. You may check out Step 4 in our last project to see how to conduct a similar test. 

 

Step 5: Building the Enclosure

If you are just building this project for experimentation, you may not want to invest time and money to build an enclosure for your visualizer.

However, we have some time on our hand while working on this project and so we decided to build a simple enclosure.

See the photos above for our enclosure. We will however not delve into the details on how we build it here.

 

Step 6: Let in the music and ENJOY

Though the OLED graphic display used for this project is small, it is still quite mesmerizing to watch the display dance to the music.

For this project, we have created 3 different display effects for visualizing the audio spectrum. You may create you own unique display effects for your audio spectrum visualizer project. You may also try out using different types and form of displays for audio visualization.

The JF Stereo Audio Spectrum Visualizer kit is also suitable for use in our Arduino based Bi-color LED Matrix Audio Spectrum Visualizer instructables project as well as the 3D Stereo Audio Spectrum Visualizer instructables project. You may check them out if you are interested.