The display is made up of 18 LEDs organized into 9 segments where there is a blue and red LED in each segment. There is a single button that the player uses to control where they will place their mark. There is also a micro-USB port that is used to power the card.

I used an ATmega328P-AU in a TQFP package as the brains to control everything. It is bootloaded with the Arduino Uno bootloader since I found that to be the most convenient and low-cost way to program it (although there are other ways to do it).

I've posted the schematic and code in case you would like to make your own!


Part 2:

Part 1:

Next Steps

This is still a project in progress with some flaws from when I designed it in college will less engineering knowledge, so I plan to continue improving it! Some planned next steps are:

- Using charlieplexing on the LEDs to reduce the number of pins needed.

- Replacing the microUSB port with USB C or a coin cell battery for power

- Improving the tic-tac-toe algorithm to something more complex, like Min-Max

- Replacing the physical button with capacitive PCB pads