Interactive LED Music Visualizer

Any microcontroller with 3.3V and 5V pins will suffice. Any analog potentiometer and size momentary button should work. Depending on your intent, the trimpot and buttons may not be necessary.

• Trimpot – The trimpot is only used to adjust the brightness threshold, so, if you want maximum brightness, you don’t have to worry about incorporating it.
• Buttons – The three buttons cycle visualizations, color schemes, and shuffle mode respectively, so, if you want to do without those features (and just use shuffle mode all the time), that’s also a possibility.

If you’re compiling from the Arduino IDE or similar, you’ll want to snag the the NeoPixel Library since the code used is heavily based on it. The resistor and capacitor are not required, but they will help prevent possible damage to the LEDs. Any resistor between 300–500 Ω can be used.

It is also suggested that you use an Arduino and Breadboard Holder to simplify wiring and to mount the LED strip:

A small notch was cut in the Breadboard Holder to hold a piece of MDF, on which the LEDs are attached.

Recommended Reading

Before embarking upon this tutorial, you may find the following links useful:

• Arduino.cc
  • Arduino Sketch Tutorial
  • Arduino Reference
• How to Use a Breadboard
• Wikipedia: RGB Color Model
• WS2812 Breakout Hookup Guide
• Sound Detector Hookup Guide
• How to Power a Project

Since we’re using the NeoPixel library, it may also be a good idea to get familiar with the NeoPixel Documentation.

Assembly

Depending on your setup, the project may not require any soldering! The few exceptions will probably be soldering some pins to the sound detector, and, if you’ve cut a roll of addressable LEDs in the middle, you’ll have to solder some wires to the starting LED’s pins. If you’ve never soldered before, I highly suggest taking a look at this guide to solder.

Below is also a general chart for how the pin(s) on each component should be routed and an accompanying diagram. Before you begin, here are some things to keep in mind:

• Be conscious of the orientation you think would allow the sound detector to take optimal readings for your intentions. Bending the pins to hold the sound detector perpendicular to the breadboard is a recommended option.
• Electrolytic capacitors are polarized, so how they are oriented is important. Make sure to place the side with a white stripe and a negative symbol into a negative current (ground) and the other into positive current.
• Resistors and pushbuttons are not polarized.
• Trimpots are not polarized either, however their middle pin is the analog output, so don’t power that directly.

The pins used in the diagram and the code are in parentheses. If you use a different pin, don’t forget to change it in the code as well:

The circuit should look something like the diagrams below. If you just want the LEDs to react to sound using one visualizer and one color palette, you can build the simple circuit on the left. If you want to take advantage of all the visuals, palettes, and shuffle mode, you can build the full circuit on the right.

Simple Circuit	Full Circuit

Fritzing diagram for the circuit as described above. Click the images for a closer look.

After assembling the circuit, you should have something similar to the image below. Depending on your setup, you may have less components.

Sound Detector Notes: The microphone used is not a sophisticated, logarithmic sound receiver like your ear; it is only measuring compressional waves in the air. Consequently, the microphone is more likely to detect and/or prioritize lower-frequency sounds since they require more energy to propagat, and therefore oscillate the air more intensely. Also, a resistor can be placed in the “GAIN” slots to modify the gain. Standard gain should be sufficient for our purposes, but, for more info, visit this tutorial to modify the gain.

https://learn.sparkfun.com/tutorials/