“A business card that can play the classic game of Tic Tac Toe.
With the internship application season in full swing, I decided to make some PCB business cards that I can give away to hopefully stand out from the crowd (well, as soon as the pandemic is over and in-person interviews are a thing again…). This card specifically plays the classic game of tic tac toe.
Like normal Tic-Tac-Toe, there is a grid with 9 positions that a player can place their mark. One player is Blue and the other player is Red instead of the traditional X and O. Your current position is marked by a blinking blue or red LED. Pressing the button quickly will move you to a new position. Once you are at the desired position, you press and hold the button to place their mark and the turn moves to the other player. The first player to get three marks in a row wins.
The card is set to 2-player mode, but there is also a single-player mode that the user can activate by pressing and holding the main button for more than 5 seconds. The display will show a “1” to indicate single-player mode. To switch back to 2-player mode, the user just has to press the main button again for 5 seconds. The display will then show a “2” to indicate 2-player mode.
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.
An ATmega328P-AU in a TQFP package is used 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 have attached the Schematics and Code in case you are curious about how it works and would like to make your own. It includes the fixes discussed in the video. However, I did not include the Board Design because I believe business cards should be unique and reflect your own style.”