My first personal circuit board project which I took on sort of like a hackathon to get done fast so I could show potential employers in the summer of 2019. Designed, ordered, assembled, programmed and debugged in the space of two weeks! Unfotunately I didn't get to show it off much given my limited number of interviews, but still proud of it.
I initially forgot to buy one SMD resistor, so had to use a through-hole one.
The design is pretty simple looking back, basically the heart of an Arduino Nano with four shift registers daisy-chained to control the LEDs on board. There are two buttons for user input and two rows of 16 LEDs each resulting in the games and UI/UX being pretty simplistic. Power was supplied through a 9V battery that hung off the board going through a linear regulator.
I made two versions of the design, and commited to having the second built and assembled.
By replicating the heart of an Arduino Nano on the board, I could program it just like one through the Arduino IDE. One however was that instead of using a USB-UART interface and the Optiboot bootloader to program the chip, I used the AVR-ISP interface using an Arduino Uno as an ISP.
My code organization was pretty simple and I tried to make it easily scalable. I decided early on that I would make a seperate file for each sort of "stage" the user was in, so mainmenu and one for each different game (e.g. stacker), as well as one for all the shared functions like updating the screen so they could be maintained easier. I now realize that what I had accidentally created was a Finite State Machine (FSM), and a project specific library.
The board was designed in EAGLE (based on release dates, probably v9.4.0). Code was written in the Arduino IDE v1.8.9.