3D LED RGB Matrix

The LED Cube is simply a matrix of LED’s cathodes are attached in columns and anodes in entire layers. The layers and columns are then connected to micro-controllers and using multiplexing the LED can be made to show visual patterns .

This project was a design failure because I did not follow a design process. The section below details what I would have done given my new design processes versus what I actually did.


The finished LED Matrix


Controlling the matrix via infrared RC

The first step of the design process is to define the problem. Identifying the problem was simple (in this case). The client, my teacher, needed a working LED matrix. But I did not sit down to seriously consider my stakeholders and the objectives and requirements. I should have realized that one primary stakeholder was myself as the assembler. A second stakeholder would be the micro-controller with limited and confined number of IO pins. A third stakeholder was my teacher who wanted a well-constructed, aesthetically pleasing LED matrix.

This would have led to the objectives of easy to assemble, compact and visually appealing. Instead I naively constructed and bent the pins of the LED in such a way that when the layers had to be put together, some pins would have be in the dead center and that would make them very difficult to reach. It also required wires jutting out of the bottom. I gave no thought to making the project look good. Finally, with respect to the micro-controller, I used 20 gauge wire and this lead to enormous problems later on when inserting 52 wires into a micro-controller. I eventually had to cut 30 cm or so off and solder 52 individual 8 gauge pieces to the ends of the 20 gauge wires.



My second biggest mistake was progressing without prior research. The LED matrix is a common project and there are a lot of online guides depicting proper procedures, any one of which I could have adopted. It turns out that there are specific, more efficient ways to bend the pins of the LED and it is far simpler to construct in columns as opposed to layers. These designs all had the capacity to be reference designs that could have been adapted for my needs.


Excerpt from: http://gemlit.com/howto/
A much better construction methodology

The second step is conceptualization which I effectively skipped. I applied the first and most naïve design: layer the LEDs , hold them on top of each other and solder stiff wires that would act as columns. The columns ended up being quite obstructing. Considering alternate designs right now, I could have used wire threads. In addition as to the overall layout, why did the columns have to extend into a base? The LEDs could have been made to hang. These are just some sample ideas. The next phase would have been to analyze and critique.

As stated above, I effectively skipped this step too. If I critiqued my design I would have realized all its shortcomings. From exposed wires, confined space and visually obstructing columns; all of these were problems.

The next step, Prototyping, had I done it, would have lead to the discovery of exactly how difficult the column pattern I used was. As stated above, the LED pins were bent in such a way that the inner LEDs were difficult to attach to columns. By the time I started attaching the columns, I had already bent and soldered the layers. I had invested too much. I could have used inexpensive, cheap LEDs and built a 2×2 model before working on the full 64 RGB LEDs. I cannot stress the importance of prototypes!

Finally there was no refinement. I did not do any detailed design investigations. In particular, I did not consider the gauges of the wire (as stated above) or anything else like the material of the base or its dimensions. You can see from the picture that the base ended up being too small to encompass the micro-controller and wires and thus I had to have a wire sticking out.

This project was a design failure because I did not follow a design process. The section below details what I would have done given my new design processes versus what I actually did.

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