Tic-Tac-Toe Pico Card

Spent just a little time fixing some bugs cuz I accidentally swapped the order of the LEDs pin assignemnt and the NEXT button so it glitched during the gameplay
Anyway I also cleaned up the repo and ready to ship!!

Added the AI feature!!! THIS IS SOOOOO COOL
i implemented the Minimax algorithm (which is a recursive algorithm for choosing the next move mostly in two-player) game from this github repo
But I also faced some issues like the AI program would occupy the entire MCU’s thread and it took a very long time and halted the waiting animation i was trying to add
But then i discvoered the alpha beta pruning which was meant to optimize the algorithm, and it really sped up the entire process alot especially how it reduced lots of workload and steps

OOOOOOO FINALLY FINISHED REFLOWING ANOTHER BOARD!!!
This time it works perfectly well, both the game and the NFC
Now ive confirmed the hardware runs perfectly, i will start focusing on the software
To be added:

• Little tic tac toe AI
• Optimize the code by removing all global variables (bruh i sucked at coding

Spent 2 hours reflowing the entire board!! It almost works 100% but i messed up the USB port……I think I migth have accidentally melted the plastic contact in the port when hot airing it
I thought the shield pins should be soldered using soldering iron, till i realized how most people used solder paste, but it’s already too late cuz its nearly impossible to melt my high temp solder

Another huge breakthrough!! my NFC works flawlessly on my iphone 14 and another android phone!!!
But idk why my mom’s iphone 15 doesnt respond at all (i think it might be her problem lol)
Anyway i really thought reflowing it without stencils would be tough but acc it was not at all lol

Alr just created the bom file and added everything to the cart
Btw I also decided to include all color LEDs just in case lol
On top of that, I also sorted all the parts for my RP2040 custom devboard

3 hours!? DAMNN lapse was kinda tripping when I was working and I thouht it was only 45 minutes……..(no wonder why it felt like forever :)
Anyways here’s what I did

• Reread the document for the NFC chip and realized that a 220nF cap is required
• Polished the PCB layout. including replacing 0.1uF with 1uF for 3V3 and 1V1
• Updated Readme and Created new release
• Re-rendered the new front layer pcb
• Ordered PCB

AHHHHHHH this is getting kinda frustrating……….
Now I have two options for the charging IC

• MCP73831 (fits better but then I gotta deal with unwanted dicharging and battery protection)
• MCP73871 (very overkill, very unnecessary)

Selected the battery and its associated parts:

• MCP73831 (the charging IC)
• LIR2450 (the battery)
• Keystone 3008 (battery holder)
  *** Still looking for battery protection IC

the image in the previous devlog is not showing, but it’s fine after doing some tuning and modification to the NFC here’s the beautiful result
*** IDK why the images in the last devlog aren’t showing

Added some design to the front silkscreen!! And I also rendered the board in blender

I spent an hour fixing the NFC and I finally found out the reason!! I FORGOT TO CONNECT THE OTHER ROUTE, that’s simply why lol

GUESS WHAT I began to build V2!!!
This is what im gonna be focusing on

• Fix NFC feature
• Add coin cell battery
• Better Design on both front and back
  btw I spent an hour doing research on how to add battery and learning figma lol

V1 finally done, just spent some time updating my repo and posting the first release!
I also planned out the V2:

• Fix NFC feature, probly redraw the antenna ig
• Add a reset button
• Add a battery
• Add silkscreen, mask design with all my information just like a proper business card
  Just one last glance at my beautiful MCU :)

FINALLY DONE!!!!! I finished the game logic and flashing animation when either of the player won or a tie happened!!

Instruction

• Player 1 is orange, and player 2 is red
• Press left to move to the next grid
• Press right to select the grid
• Just like any tic-tac-toe rules

For the past two hours I finally made the control system work!!!!

• Press left button for next
• Press right button to select
• The pointer will automatically skip the selected grid
• The pointer will go back to the first grid if it reaches the last grid

HUGE SUCCESS, I finally got the board and everything except the NFC seems to be working perfectly!!!

• Tested out all the LEDs
• Installed Micropython
• Installed Thonny
• Coded left and right buttons
• Watched Micropython Tutorials

Here’s what I did for the past two hours:

• Excluded NFC from the copper pour
• Redesigned NFC Antenna
• Chose all the parts and edited BOM file, I repackaged everything thrice
• Triple-checked the 3D viewer
• Tried my best to replaced extended components with basic

PS: it’s 70 USD (89 CAD when I checked my bank account)!!!! SO I SPENT SO MUCH TIME ON CHECKING TO MAKE SURE EVERYTHING GOES RIGHT

For the past two hours I was trying to add NFC feature to this card!!!

For the past hour I was cleaning up everything, including:

• Swapping 1V1 capacitors with 3V3 (I mean the position) cuz 1V1 is crucial for chip logic supply and more delicate I suppose
• Adding more GND vias
• Rerouting a couple wires to the LEDs to allocate more space for NFC
• Cleaning up references
• Cleaning up DRC warnings and 2 errors

Finished routing everything!!!

• Rearranged the pins
• Added tons of GND vias as usual
• Aligned USB socket with the edge

Almost done wiring the IC components!!! YAYYY
PS: I deleted to capacitors as there are two pairs of 3V3 pins very close to each other

• Finished tic-tac-toe grid positioning
• Replaced 0402 with 0805
• Researching alternative flash storage (the original one is too big)

Roughly positioned the components, mainly searching parts on JLCPCB cuz extended parts are too expensive…….

Completed the schematic and footprints!!!
Part Selections:

• 0402 Capacitors
• 0402 Resistors
• 0402 LEDs
• RP2040
• ABM8-272-T3 12MHZ Crystal (recommended by the official)
• W25Q128JVS Flash Storage
• USB-C