Though building the layers of LED Matrix is time-consuming, it is not difficult to complete them.

Most entry level hobbyist may find difficulty building the electronic circuit to drive the LED Cube especially troubleshooting the circuit when things go wrong.

For our electronic circuit, we will basically be using the MAX7219 ICs to drive the cube. We checked out similar projects at Instructables but are unable to find any using this IC to drive LED Cubes. The MAX7219 IC is originally designed to drive 7-segment LED displays. By designing our LED Cube electronic circuit based on this IC, the number of components to drive each layer of LED Matrix is very minimal.

Each layer of the 8x8 LED Matrix will be driven by the electronic circuit using the following components;

a. 1 x MAX7219 IC

b. 1 x 10uF 16V electrolytic capacitor

c. 1 x 0.1uF ceramic capacitor

d. 1 x 12Kohms resistor (1/4W)

e. 1 x 24 pin DIP IC socket

So for our 8x8x8 LED Cube, we will need 8 sets of the above components. Note that you may need to choose a different resistor value to work with the LED you are using. This resistor is to limit the maximum current the MAX7219 IC will supply to the LEDs.

To help entry level hobbyist, we tried to simplify our electronic circuit design using modular design so each circuit shall be driving one layer of 8x8 LED Matrix. You may check out the circuit block diagram to see how our circuit is connected.

To reduce error and effort to wire up the electronic circuit, we have designed a PCB containing 4 of these circuits. So you need 2 of these PCBs to build a 8 layer 8x8 LED Matrix LED cube. All the components used are through-hole components.

Our design does not have any particular microcontroller embedded in our electronic circuit to drive the cube. It shall be driven externally by any micro-controller via SPI interface. For this project, we will be using the popular Arduino board (Nano) to drive our cube using just 3 signal wires (SPI) and 2 power wires (5 V DC). You may use the more commonly available Arduino Uno instead of the Nano as they are very similar except for the size factor. You may also adapt the program codes we will be using to work with any other microcontroller you wish to drive the LED cube.

Do note that all the components are to be soldered to the bottom of the PCB. Look out for the silk screen labels (BOTTOM) or (TOP) on the PCB. One of the photos above shows one of our PCBs with only one of the circuits populated with the required electronic components.

Each modular circuit is demarcated by the white silkscreen line running across the PCB. In order to connect the individual circuits together, we need to use jumper leads/wires to solder from one circuit to the adjacent circuit. The photo above shows the jumper leads we used. They are made from the cathode legs we trimmed off in Assembly Part 1 Step 6. We need 5 jumper leads to connect from one circuit to the adjacent circuit. So for each PCB, we need to solder 15 jumper leads. The photos above show the location of the jumper leads to be soldered on the first and second PCBs (highlighted in RED).

Most LED Cubes are built as a whole so if one LED were to fail in the middle it would be very difficult to access and fix it. For our LED Cube design, we used a 5-way angle female header soldered to the first PCB and a 5-way angle male header soldered to the second PCB. This is to enable the 2 PCBs complete with LED Matrix layers to be connected together to work as well as to separate them apart for ease of access for replacement of faulty LEDs around the middle of the LED cube if the need arises.