Gradled Mini: Prototype Modular Discrete LED Display

This project came into being during my senior year of college at UW-Madison as a personal side venture. In May 2019, I complete my undergraduate schooling. It is not uncommon for students to decorate their graduation “hats” to personalize them and make them stand out in the crowd of graduates during the commencement ceremony. Typically, people create artwork related to the university they attended (i.e. UW-Madison) and use markers, glitter, little stickers, etc to create the decoration.

When it is my turn to partake in commencement, I also want to continue the hat-decorating tradition, but with a special twist: I want my hat to light-up and be able to show arbitrary artwork. Basically, I want to put an LED display on my head. I want a graduation LED hat. Thus, my Gradled project was born. (Pronounced: grad - led)

Project Requirements
After brainstorming what I wanted the end result to look like, I came up with a list of requirements for the project design phase:

Cheap as possible (I didn’t want to shell out ~$100s just for my hat customization)
Extendable to more than just graduation hat toppers (maybe wall art)
These generic requirements became specific requirements after more research:

Single color, discrete LED matrix
Tileable for arbitrary rectangular display configuration
One PCB design that can be populated / configured for various paneling arrangements
Low power consumption (i.e. powered from coin cell battery)”

Link