Finished KineticBoard HAT Schematic

I spent a few hours finishing the schematic for the KineticBoard HAT, an extension board that allows the Pi Pico to control motors.

Additions

Rather than using a standard Li-Ion to power the Pico and a really small power bank to power the Pi, I decided to just use one: the Li-Ion. For this to happen, the PCB would need to convert 12V to 5V and expose this voltage through a USB-C connector. I decided to copy & paste my old buck converter schematic, but I had to pick different resistance values such that this formula V = 0.925 * (1 + R1/R2) yielded ~5.1V. This seems easy, but I wanted to use some resistors that I already had. I decided to make a C program that picked the most optimal values for this voltage divider. The program works by following a 2 pointer algorithm which adjusts the numerator and the denominator by shuffling through a sorted list of the resistance values, and finding the ones that are closest to the target voltage. I also expanded on my old buck converter by making the +3V3 net controlled by a switch, just so that no weird stuff happens if I connect both the PC and battery to the board at the same time. Lastly, I added the 6-pin JST connectors, the motor driver, and a few status LEDs. I put everything in the PCB editor in the end, and I’m honestly terrified of routing this thing, but that’s a problem for later lol.