This is a 6x6x6 RGB LED (Common Anodes) Cube controlled by a Bluetooth App using an Arduino Nano. The entire build is easily adaptable to a say 4x4x4 or 8x8x8 Cube. This project is inspired by GreatScott. I decided to go for a more sophisticated build using bigger leds (8mm), with less distance + adding Bluetooth communication which makes adding new functions so much easier and also adds the capability of building an app to control the cube. This also allows me to e.g. code a Snake Game (3rd showcase video at the end). On top of that I added an Audio Visualizer mode which allows the cube to visualize an AUX Input e.g. Music using an MSGEQ7( showcase video at the end). Additionally I wrote an AnimationCreator application in Java with an easy to use UI to create and tweak Animations, so that anyone can build custom animations very quick. So the Sketch + Bluetooth App provides a framework for any LED Cube configuration and with the Animation Creator you do not need to worry about implementing custom animations.

Project Overview

The "Cubo Volumetric Display" is a high-density 6x6x6 RGB LED matrix that serves as a 3D canvas for digital art and gaming. By soldering 216 RGB LEDs into a precision grid, the project creates a volumetric space where animations, audio visualizations, and even a 3D version of the classic game "Snake" can be played. Controlled via a custom-built Bluetooth App and a dedicated Java Animation Creator, this project demonstrates elite-level electronics engineering, from high-speed multiplexing to constant-current power management.

Technical Deep-Dive

• Constant Current Multiplexing (TLC5940 Chain):
  • The Driver Math: Driving 216 RGB LEDs requires controlling 648 individual cathodes. To manage this on an Arduino Nano, the project daisy-chains seven TLC5940 ICs. Each TLC5940 provides 16 channels of 12-bit PWM control with integrated Constant Current limiting. This ensures that every LED in the cube maintains identical brightness regardless of how many other LEDs are currently active.
  • Daisy Chaining: Data is clocked out from the Arduino via SPI. The 7 chips effectively act as one giant 112-channel shift register, allowing the Nano to set the color intensity for an entire layer in a single high-speed transmission.
• Volumetric Scanning & POV:
  • The cube doesn't light up all 216 LEDs at once. Instead, it uses Persistence of Vision (POV). It lights up one horizontal 6x6 layer at a time. By cycling through all 6 layers at a frequency higher than 60Hz, the human eye perceives a solid, flicker-free 3D image.
  • High-Side Switching: To handle the current of 36 RGB LEDs (up to 2.1 amps per layer), the system uses IRF9540 P-Channel MOSFETs. These act as high-speed gates, turning the power to each layer's common anodes on and off under Arduino control.
• Java-Based Animation Modeling:
  • The project includes a custom Animation Creator application. This software provides a 3D GUI where users can click individual "voxels" to set colors and frames. The software then compiles the 3D coordinates into a binary data stream optimized for the Bluetooth serial protocol.
• Audio and Game Logic:
  • MSGEQ7 Integration: In visualizer mode, the cube maps the 7 frequency bands from an MSGEQ7 chip to 3D "frequency bars" that grow from the floor of the cube.
  • 3D Snake: The game logic manages a coordinate array (x, y, z) for the snake's body. Collision detection is recalculated for every frame across the 216 potential voxel positions.

Engineering & Construction

• The Prototyping Jig: Precision is paramount. The author utilized a wooden jig with drilled holes to hold the 8mm LEDs in a perfect 6x6 grid during the assembly of each layer. This ensures the final cube is perfectly square and the internal "bus wires" (tinned copper) are straight.
• Ribbon Cable Management: To prevent a "nest" of 216 wires, 40-pin rainbow ribbon cables are used to connect the base board to the various layer MOSFETs and TLC5940 channel headers.
• Power Budgeting: A full-white cube could theoretically draw over 10 Amps ($216 \times 3 \text{ colors} \times 20\text{mA}$). However, because only one layer is active at a time, the peak current is reduced to approx 2.2A. A robust 5V 4A power supply is mandatory to prevent voltage brownouts during intense animations.
• Firmware State Management: The Arduino sketch acts as a passive renderer. It listens to the HC-05 Bluetooth module for new frame data and stores it in a volatile buffer. This decoupled architecture allows for infinite animation complexity, as the heavy "processing" is handled by the desktop app or smartphone.

Links to the Arduino Sketch and Bluetooth App:

RGBCube_Arduino Sketch (Github)+Animation Creator.jar

Cubo Bluetooth App (Github)

Parts list for the Cube:

• 216x RGB LED (Common Anode) (8mm)( AliExpress / Ebay)-> 6x6x6=216
• Ribbon Cable (1m 40Pin should be sufficient) ( AliExpress / Ebay / Amazon )
• Female and Male Headers (at least 4x40pin each) ( AliExpress / Ebay / Amazon )
• Tinned Copper/Silver Wire 0.8mm (~25Meter) ( AliExpress / [Ebay](https://www.ebay.com/itm/4m-Silver-Plated-Craft-Metal-Beading-Wire-Cord-0-8mm-HOT-S6U9-MT/283139378482?epid=2037339457&hash=item41ec6c0d32&enc=AQADAAAC8FjVrDbVsZ8oH%2F8PNHtt9VX4%2Fw7FZcmMuqsX8uaFEduVeiTAjVhui502iQeOTswOeM8dXuA6Tcwqevu50kZYBzTduUscP85%2FA3XLGYK4CkHnrWv92ja4kUQzF4m1VZyh2ito1HG97WFYYk7FZU6b%2BZ1%2FyZVxblVG0XtvN0n9M2Moig57BvuetcaR7cju3Merb6uyrCsIa6RJQ0DZ0fDXdhhO81NiJg8vLC4uWgcV9dnhvx3sAUkS3gpPWjKvEuNZ8g2QZ8EbGypOMfvkKz%2FZGucvUyTkCgP3g1u0SAYOkW8BpVYHqxVYYkkmKSs9hleXBVrzWtjsrGoEbvOHwxXuyqx9Ow9LBSMH6i2Oif2ALkmUOlhl7hje1oYJBXCqP302NEoN0ub%2Frdzb7Btz5%2BYQKdTNZ3DZculq%2FX%2FtcT%2B%2Fj8XVK8den5%2BSD6g4dUqwxIKyrKFHhnZR6b%2Fw8etrL1b%2BMyEFzooGzRptgAaCLo5ssz8Ceo%2FL4X6IFBsIG%2FnuLjWuLS9sVRDryMy6JtxgeQyyS1gzSmfYXJW8YD6u1%2BxMAgPgDFwt4nOXJ%2Fm%2BHy1mTC61CVT90zIj1TjwcJXWFqpJ%2BzUwj%2Bs8fKIlX%2BfABufV6XsJ9LK0ZSyDjwEnP%2BZu0P8TV%2BGmalqBva%2BcM3bCW9sMsTS0cG%2FDi11GoFH4tzVpzZeEanbrJS4Ec25Oq13Nax53tc9%2Ba5Hj0ZxU%2BYTgt2AjEohh021clWeZwmbp2DL9B8E5SCwPXHpxFFPdK3OSLZCPVbfZ%2B75LWnysyk2RODliq