Direct I/O Implementation

Direct I/O nxnxn Cube

This cube only requires a handful of discrete components a little bit of soldering to make the cube which fits on the breadboard.

See description here: https://github.com/MajicDesigns/MD_Cubo/issues/11

I/O mapping (Arduino Nano and 3x3x3 cube example)

3 transistors (A949 PNP BJT's) are used to open each layer circuit to ground.

• 5V from power rail to pin 1 on the three BJT's direct connection
• 1K ohm resistor on BJT pin 2 to cube layer 0 common cathode
• 1K ohm resistor on BJT pin 2 to cube layer 1 common cathode
• 1K ohm resistor on BJT pin 2 to cube layer 2 common cathode
• D13 on Arduino to a 100 ohm resistor to pin 3 on the layer 0 BJT
• D12 on Arduino to a 100 ohm resistor to pin 3 on the layer 1 BJT
• D11 on Arduino to a 100 ohm resistor to pin 3 on the layer 2 BJT

LEDs in the layer are numbered by column:

2  5  8
1  4  7
0  3  6

LED in each layer have a direct connection to Arduino digital I/O as follows:

LED  0   1   2   3   4   5   6   7   8
Pin  D4  D7  D10 D3  D6  D9  D2  D5  D8

The hardware architecture implemented shown in the schematic below.

Implementation Overview

Cube data is buffered in memory organized as vertical layers of 9 bits (1 word). At each refresh, the I/O for each LED in a layer (_LEDLayer) is set and the Arduino pin corresponding to that layer (_enableLayer) is set to ground (LOW) to enable the circuit for that layer.

The animate() call is used to scan the refresh of the cube. No interrupt timers are used in this implementation.

No intensity changes are implemented in this architecture.