LED light cubes are a hugely popular and fun project and with the help of the Hobby Components kit you will have all the parts to build your very own. Building on the popular 8x8x8 cube kit (HCKITS0022), we decided to create a through-hole version for those of you who are better suited to this kind of soldering. The kits we sell include all the necessary components to build the driver base board and 64 3mm LEDs to build the 4 x 4 x 4 cube. The kit is offered in several colours.
Some familiarity with soldering is required to construct the kit.
So, let’s get started! The guide is split into two parts, the first covers creation of the base board, and the second covers the LED cube creation.
The first thing you need to do is check that all the components are enclosed in your kit. If you’ve purchased components elsewhere, be sure to check you’ve ordered the correct values for each component.
4 x 4 x 4 Cube Kit PCB
3 x 100nF Ceramic Capacitors
2 x 20pF Ceramic Capacitors
1 x 5 Pin Connector
4 x 5mm White LEDs
1 x Pin Header Strip
1 x 10K Resistor
16 x 100R Resistors
4 x 220 ohm Resistors
1 x Tact Switch
1 x ULN2803 8-Channel Darlington Driver
1 x ATMega328-PU
1 x 16MHz Crystal
64 x 3mm LEDs (Available in Blue, Green, Red and White)
Plus: A USB to serial interface cable that can be used to power and reprogram the completed cube*.
*Please see the diagram at the bottom of this guide for how to connect the cable to your cube.
In order to built the cube, you will need a few tools:
Soldering Iron (Ideally with a fine tip)
A piece of perspex or plywood which will be used as a jig for soldering the LEDs that make up the cube
3mm drill bit and drill
A pair of small long nose pliers
Part One – Building your LED Cube: PCB
Soldering tip: When soldering components to a circuit board it is always best to start with the smallest components first. This helps keep the board flat and stops access to pads from being restricted by larger components. The first step is to start by soldering the resistors and capacitors. In your kit these will be marked appropriately. The orientation of most of the components doesn’t matter. We will point out any components where the orientation does matter. In these cases it is important to make sure you have them inserted correctly.
Locate the following pads on the PCB and solder the appropriate resistors in place.
Pad R1 – Resistor Value: 10K (BROWN, BLACK, BLACK, RED)
Locate the X1 pad on the PCB and solder the crystal in place.
Locate the following pads on the PCB and solder the appropriate capacitors in place.
Pads C4 and C5 – Capacitor Value: 20pF
Pads C1, C2 and C3 – Capacitor Value: 100nF
Locate the following pads on the PCB and solder the switch in place. Note that the switch is a tight fit, but it does push through and sit correctly on the PCB. Note that the orientation of the switch is important – the legs of the switch should be on the left and right hand sides of the components as in the picture below.
Pad SW1 – 4 pin Tact Switch
Locate the following pads on the PCB and solder the appropriate IC in place. Note that the orientation of the IC’s is important – at one end of each IC you will notice a semi circle cut into the case. When the IC’s are inserted into the board these should be on the left as in the picture below.
Pad U1 – ATMega328-P IC
Pad U2 – ULN IC
Edit: If you have a version V1.1 PCB (marked V1.1 in low right hand corner) you can skip this next step and move on to the connector…
On the opposite side of the board (black side) use some solder to bridge pins 8 and 9 of IC U2. Reference the image below for the correct pins.
Locate the five holes shown in the image below on the lower edge of the PCB and solder the right-angled header pins in place. You can solder the connector on the top or bottom side of the board. It’s up to you!
5mm LEDs (Feet)
Locate the relevant pads and solder each of the four 5mm LEDs in place. Note that the orientation of the LED’s is important – the short leg of the LED (called the cathode) should be oriented to the outside of the PCB.
Pads D1, D2, D3 and D4 – 5mm LEDs
The LED connectors are each stripped from the enclosed male to female header strip. Carefully snap off each pin and solder to the black side of the PCB as shown below. There are a total of 20. Note that whilst creating our demonstration cube, we stripped off the black plastic from all headers (by lightly squeezing pliers around the plastic until it came away), this isn’t a requirement, it just gives a slightly better look to the finished PCB.
So, you’ve managed to complete all the electronics – Now time to move on to the cube part of the guide.
Part Two – Building your LED Cube: the Cube
After soldering LEDs for the 4x4x4 LED (all 64 of them!), this one was a doddle!
To build your LED cube you will need to solder the 64 LEDs supplied in your kit in to four sets of 4 x 4 grids. This will take a little time and so it is important that you understand how to construct these grids before starting.
Whilst with a little care you can construct the grids by hand, it is recommend that you first construct yourself a jig/template as this will allow you to construct the grids quicker and with more accuracy. To do this you will need a piece of perspex, plywood, or any stiff material you can drill holes into measuring at least 5cm x 5cm (in this example we just used a piece of thick cardboard). You will need to drill a set of 3mm holes arranged in a 4×4 grid. The centre of each hole can be marked easily by placing the PCB on top of your jig material and using a fine pen/pencil, or if using cardboard, pushing a pin through. The holes will then all be exactly where needed to create the jig.
Before you start…
Tip 1: Before you start soldering your LEDs together we strongly recommend testing each LED first. You can do this by using your newly built PCB as an LED tester! Simply power the PCB up by connecting the supplied USB cable. Connect the RED cable to the pin marked 5V on the PCB, and the black cable to the pin marked GND. No need to connect the green and white cables, they are just for if you want to reprogram your cube. Next check each LED by inserting it into the two sockets shown in the image below.
Testing the LEDs
Make sure to connect the LED to the two sockets shown in the image and with the shorter leg of the LED inserted into the outer socket. With the PCB powered the LED should randomly turn on and off as the cube runs through its demo.
Tip 2: When bending the legs of the LEDs we recommend using a pair of long nose pliers. This will help to avoid applying mechanical stress to the base of the LEDs when bending their legs.
Don’t worry if any of your LEDs don’t work or you make a mistake – we provide extra LEDs in the kit to help cover for any problems.
Insert one row of 4 LEDs into your template as shown in the image. Note the orientation of the LED legs with the short legs at the top and the long legs at the bottom. Carefully bend each long leg at a 90 degree angle at the base of the LED so that it points down.
Then carefully bend the short legs by 90 degrees near the base of the LED so that each short leg is touching the short leg of the LED to its left. Note that when bending the short leg, bend it a couple of millimetres higher than the long leg so that it can pass over the long leg of the LED to the left without touching it (see above left diagram).
Make sure these legs to not touch the longer legs of each LED and then apply a small amount of solder to hold them in place.
Repeat step 1 for the other 3 rows. The result should look like the image above with each short leg soldered to the short leg of the LED directly to its left and no short legs should touch a long leg.
You have now completed one 4 x 4 grid of LED’s. Carefully remove this grid from your template and set it aside. Now repeat steps 1 to 3 to create 3 more identical grids.
Your cube grids are now constructed. All the LEDs of each grid should be pointing in the same direction. Now insert each grid into the controller board. Please make sure you disconnect the controller board from your computer before proceeding. Be careful when inserting the legs of the LED’s into the sockets. They are a snug fit but don’t apply too much force otherwise you may bend the leg or break the socket. You will find it easier to insert the legs using a pair of long nose pliers.
Solder the remaining unconnected short legs of each of your 4×4 grids to the short legs of the grid directly to the right. Start with the top row of legs and work your way down. Before soldering make sure each 4×4 grid is evenly spaced so that the entire cube is square.
Repeat for each layer.
The final step is to connect the short legs of each horizontal 4×4 grid to the 4 additional row driver pins on the edge of the controller board. Reference the red lines in the above image for the order. Each of the 4 controller pins should be connected to one of the horizontal rows with a piece of wire. If the wire you are using isn’t insulated then you will need to make sure that it is slightly bowed out so that it doesn’t touch any of the LEDs it runs past.
At this stage the cube is complete! If you built one, well done! If you are thinking about building one, you now know how easy it is. Pop on over to Hobby Components and order your kit to get started. The order codes are HCKITS0041, HCKITS0042, HCKITS0043 and HCKITS0044.
Powering your cube with the supplied serial USB cable:
Supplied with the kit is a serial USB cable. To apply power to your cube connect the cable as shown in the above diagram.
The contents of this guide are copyright Hobby Components Ltd and may not be copied, reproduced, or reused elsewhere without permission.