Help designing a music visualizer for a 12x12 LED screen

In summary, the conversation is about designing a LED interactive screen and the design of a music visualization system. The designer is new to this area and needs suggestions on how to continue the project, specifically in terms of using op-amps to filter the input signal. The conversation also touches upon different ways to digitize the signal, such as using FFT, and different display patterns, such as the spectrum or time domain. Suggestions are given for using FFT and designing a microprocessor-based system, as well as a suggestion to use Lissajous patterns for a fun visual display.
  • #1
AnnaP
4
0
I am working in a group for designing a LED interactive Screen. My part of the project is the design of the music visualization system. I am new in this area, but I know I need to use some op-amps to filter the input signal from the mp3 player.
Could anyone give me any suggestions on how to continue on the project? I know there are several ways to do it (there are multiple ways to digitize the signal eg. FFT ) but I’m not very sure which one to follow.

Any help would be appreciated!

Thank you in advance!
Anna:)
 
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  • #2
I'm not sure that I can help without giving you the whole design.
You would have to go digital early in the circuit to use FFT's.
What can you do with band-pass filters?
 
  • #3
You need to define what you want to visualize. Do you want the spectrum, or the time domain? Or, something else (like patterns based on frequency content)

If you want the spectrum you need to digitize and run the FFT. If you want time domain, you need to digitize and decide how to trigger.
You need to anti-alias filter before you digitize.

Look at winamp visualization plugins and decide EXACTLY what you want to display.
 
  • #4
meBigGuy said:
You need to define what you want to visualize. Do you want the spectrum, or the time domain? Or, something else (like patterns based on frequency content)

If you want the spectrum you need to digitize and run the FFT. If you want time domain, you need to digitize and decide how to trigger.
You need to anti-alias filter before you digitize.

Look at winamp visualization plugins and decide EXACTLY what you want to display.
Thank you for your reply! I have to display the frequency domain and when this is done I will try and do some other frequency related patterns as well.
I can't find enough information on how to do that though. Do you know any page that could be of help? Thanks!
 
  • #5
.Scott said:
I'm not sure that I can help without giving you the whole design.
You would have to go digital early in the circuit to use FFT's.
What can you do with band-pass filters?

I guess I will have to go the digital way to use FFT. I am currently researching about filters because it is the first time I will work in this field. If you have any design that could help or know where and how to search for it, it would be very appreciated. Thanks!
 
  • #6
Since you mentioned FFT and a 12x12 array of LEDs, I was thinking you wanted to show the amplitude of 12 spectral bands on a bar-chart type of display. But now I wonder if you really had any specific display pattern in mind.
The hardware design for pure digital would be some microprocessor with an A-to-D converter and 24 discrete outputs (DO). Once the wave form has been captured, you can drive the 12x12 array by clocking through each row with 12 DOs any using the other 12 DOs to select which LEDs in that row should be lit. What you code in the microprocessor would be whatever you want (FFT, etc).

The PIC24 series (below) may work for you - but there are many others. There's more than a trivial amount of design work to do.

http://ww1.microchip.com/downloads/en/DeviceDoc/00001032n.pdf

A more analog design might be simpler - but less flexible.
 
  • #7
.Scott said:
Since you mentioned FFT and a 12x12 array of LEDs, I was thinking you wanted to show the amplitude of 12 spectral bands on a bar-chart type of display. But now I wonder if you really had any specific display pattern in mind.
The hardware design for pure digital would be some microprocessor with an A-to-D converter and 24 discrete outputs (DO). Once the wave form has been captured, you can drive the 12x12 array by clocking through each row with 12 DOs any using the other 12 DOs to select which LEDs in that row should be lit. What you code in the microprocessor would be whatever you want (FFT, etc).

The PIC24 series (below) may work for you - but there are many others. There's more than a trivial amount of design work to do.

http://ww1.microchip.com/downloads/en/DeviceDoc/00001032n.pdf

A more analog design might be simpler - but less flexible.
Thank you!
 
  • #8
AnnaP said:
I am working in a group for designing a LED interactive Screen. My part of the project is the design of the music visualization system. I am new in this area, but I know I need to use some op-amps to filter the input signal from the mp3 player.
Could anyone give me any suggestions on how to continue on the project? I know there are several ways to do it (there are multiple ways to digitize the signal eg. FFT ) but I’m not very sure which one to follow.

Any help would be appreciated!

Thank you in advance!
Anna:)
Another option for having a fun visual display with music is to drive the display in an x-y fashion. If you put a continuous sine wave (say at 60 Hz) on the horizontal axis, and drive the music waveform on the vertical axis, you can get some really fun and cool Lissajous patterns. I used to do this with an old oscilloscope and rock music back in college. It was a very popular display.

You could even adjust the frequency of your horizontal sine wave to give you the best patterns for the particular song that is being played. I don't know if the resolution of a 12x12 display is enough to get good patterns, though.

https://mbhs.edu/~jeglick/Images/TV/Lissajous%20Curves.jpg
Lissajous%20Curves.jpg
 
  • #9
berkeman said:
Another option for having a fun visual display with music is to drive the display in an x-y fashion. If you put a continuous sine wave (say at 60 Hz) on the horizontal axis, and drive the music waveform on the vertical axis, you can get some really fun and cool Lissajous patterns. I used to do this with an old oscilloscope and rock music back in college. It was a very popular display.

A bit Offtopic, but ...
I set up a dual servo amplifier to drive the deflection coils of a TV. Equalized one channel's bass to get enough phase shift to look cool.
 

1. How do I select the right LED screen for my music visualizer?

When selecting an LED screen for your music visualizer, it is important to consider the screen resolution, size, and pixel pitch. The resolution determines the number of pixels on the screen, while the size will determine how large the visualizer can be displayed. The pixel pitch refers to the distance between each LED, which can affect the overall clarity and sharpness of the visualizer. It is recommended to choose a screen with a high resolution, large size, and small pixel pitch for the best results.

2. What software should I use to design my music visualizer?

There are many software options available for designing a music visualizer for an LED screen. Some popular options include Adobe After Effects, Resolume, and TouchDesigner. When selecting a software, consider your level of experience and the features you need for your specific visualizer design. It may also be helpful to do some research and read reviews to find the best fit for your project.

3. How do I synchronize the music and visuals on the LED screen?

Synchronizing the music and visuals on the LED screen can be achieved through various methods, including using a MIDI controller or using audio analysis software. These tools allow you to map specific parameters of your visualizer to the music, ensuring that the visuals are synchronized with the music in real-time. It may also be helpful to consult with a programmer or visual designer for assistance in this process.

4. What is the best way to program the LED screen for my music visualizer?

The programming process for an LED screen music visualizer can vary depending on the software and hardware used. However, some general tips include organizing your visual elements into layers, using keyframes to control movement and timing, and utilizing effects and transitions to enhance the overall visual experience. It may also be helpful to experiment with different programming techniques and get feedback from others to improve your design.

5. How can I make my music visualizer more interactive?

To make your music visualizer more interactive, you can incorporate motion sensors or other input devices that respond to audience movement or sound. This adds an element of surprise and engagement for the audience, making the visualizer more dynamic. You can also consider adding interactive elements to your visuals, such as clickable buttons or touch-sensitive areas, to allow viewers to control the visuals in real-time.

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