ESP32 spectrum analyser VU meter using arduinoFFT and a FastLED matrix

I was struggling to understand the arduinoFFT library due to its lack of documentation, so I spent some time investigating and this is what I made. This might also work on an ESP8266, but you will have to reduce the sampling rate as it's not as fast as the ESP32.

The code is written using the Arduino IDE. It can have any number of bands, and comes with 5 preset patterns but it's easy enough to add your own providing you can work with FastLED.The image is displayed on a homemade LED matrix, using the FastLED library.

[theREALdilAndou]

Hey Scott. Keep up the good work man. I'm sorry to see how disgracefully G6EJD handled the whole copyright thing. Rip out his code and switch to audio_reactive.h from WLED (MIT licence) and remove all his credit. It's the least the guy deserves.

[mehmetaliertorer]

I have never seen a complicated topic explained so intuitively and straightforward. Such an amazing video

[Jessyplaysz]

Thanks for the video Scott. It told me just what I wanted to know.

This post is for the benefit of anyone considering using an ESP32-S3. Its A/D is not as fast as the ESP32. I ran the Sample Test sketch on a LilyGO T-Display-S3 and got the following rates
So I guess its good to around 8kHz audio which is the upper limit of what I need.

Conversion time: 60.12 uS
Max sampling frequency: 16633.61 Hz
Conversion time: 60.12 uS
Max sampling frequency: 16632.99 Hz

I then thought I could be clever and reduced the A/D resolution from 12 to 9 bits to get a higher conversion speed but alas no luck in Arduino IDE. It was identical.

[fragiggle]

Hey Scott, thanks for this fantastic starting point for my project. I made this powered by a DeWalt battery, mounted to a pole and had to heavily modify the code and hardware to get it to work in any volume level environment. I can't say how much longer this would have taken without this starting point, but I can say it would have been a lot longer.

I had the idea to do it 8 years ago and finally sat down to do it last January and found your project during the research phase. Finished it in August and took it to a music festival, people absolutely loved it.

Thanks again for the great work!

[acquireelectricity]

Hi. I built it! First I tried using my esp8266, but the latency was massive. Esp32 works amazing. Thank you Scott Marley for this tutorial.

[Hienix]

This is amazing. I've seen other videos and they aren't nearly as good as this explaning the math and logic behind.

[wclumiere]

@Scott Marley thanks for sharing, have to say it, this is so far the best video tutorial on how to use the arduinoFFT library I have seen. Keep it up. Great Job!

[javilarg]

Hi, I was about to make a 7-band audio spectrum visualizer with an Arduino Nano and a MSEQG7 chip, but searching YouTube I found this project, easier, more powerful and more impressive. Thank you.

[OmarVeiga]

Thank you so much for this project. I manages to recreate it using an 8*32 led SPI matrix and a teensy 4.0. This is an amazingly well made and explained project which I had a lot of fun with. Keep up the good work and wish you the very best :)

[dasphantom]

Hi, awesome work. I tried for so long to understand FFT and how to use it. You made it so clear. Thanks!

[azfilmarchive]

Thanks for a wonderful tutorial. My build went right to work 1st time and the different modes were a delightful surprise. My larger project is to use an IR distance sensor to track trombone slide movements and encode MIDI signals. Besides recording parallel audio and MIDI signals, I can also light 64 individual WS2801 led's in a spiral piano array. Additionally, the MIDI signal operates a silent mono synth that in turn runs your spectrum analyzer. Part an art piece and part a scientific search for patterns in microtonal music. Thanks for adding another dimension to my quest. GCH

[JohnSmith-iucj]

We need more videos of this vu meter it’s the best thing by far! Nothing else comes near!

[AnthonyHortin]

Love this! That is such a beautiful, clean and crisp Matrix that you've put together and looks fantastic with that spectrum analyser running on it. Well done! 👍

[franklincoellofranklin]

The best video I've ever seen related to FFT!

[Wellan_Qc]

Hey Scott. I know this is a massive shot in the dark but I've been having issues recreating your project because my ESP32 can apparently only read the analog pin at 14kHz. Could you share the exact board you are using or if maybe your ArduinoIDE setup is different if possible? Kinda scared to get into possible solutions like I2c. Great video by the way, got me into making stuff at home and not waiting for school projects to start being interesting.

[rgbcrafts]

ESP32 seems to be perfect for all kinds of pixelart. Your videos make me quite interested in making these projects myself.

[Edmundajw]

Great video. I have just put together a matrix using a string of WS2815 leds, rearnaged into 10 * strips of 16. I've yet to put together the code, so I'll find this very helpful, as I had intended to do something almost identical to your output. I enjoyed your explanation of the FFT, very scuccint. :)

[Marc_Miller]

Your videos are excellent Scott. Thank you for making and sharing.

[manoharmanu]

Well explained Scott, for a complete noob like me this is a life saver of a project . I'll try it out and let you know, keep doing cool stuff

[JohnSmith-iucj]

Yo you nailed it with this one I am going to try something Similar based on your code and I am super thankful for the code you provide! I was thinking about something like this for many years, even more so since studying fft and your video and the fft library are a big motivation to get going!