Human 1, AI 0 - 40 minutes of debugging and my PICO tool projects microSD card as USB thumb drive to PC

CARTINTERFACE - TOOL TO MOUNT MINI 2315 CARTRIDGE ON PC VIA USB

The Virtual 2315 Cartridge Facility (V2315CF) employs microSD cards to hold a disk volume with a file that is a virtual image of a 2315 disk cartridge. These cards are mounted on a small circular PCB that is the top of a mini cartridge, looking like a tiny version of the 2315 cartridge, with a 2x4 header that plugs into the V2315CF main box so that the disk image can be accessed by the IBM 1130 system. 

The PCB has a microSD card socket on board and is wired so that the V2315CF can access it via Serial Peripheral Interface (SPI) over the header pins. The card socket and other components are on the underside of the small PCB. The mini cartridge has a 3D printed shell glued under the PCB, forming a 2315 cartridge shape. 

For convenience, I wanted a tool that allowed me to plug the mini cartridge into a socket and have the file on the microSD card appear on a PC as a virtual disk drive, just as a USB thumb drive appears. I whipped up a small box with a Raspberry Pi Pico, a 2x4 socket and some pullup resistors as an interface box, which I call CartInterface. 

The mini cartridge is plugged into the 2x4 socket and the USB cable from the PICO is plugged into a PC in order to open the microSD card FAT file system as a virtual drive on the PC. The file on the card can be accessed (or replaced on the PC to update the mini cartridge).

WORKED WITH AI TOOLS TO BUILD THE PROJECT

Since this would use a number of libraries that I was not familiar with, plus be a first time I tried to project a mass storage (disk) device over USB, I looked for advice from four AI systems - Gemini, Copilot, Claude and Grok. They all identified the two examples of the same functionality that were published on the internet - one using the Arduino development environment and the Adafruit TinyUSB library, the other using the No-FS-FatFS-SD-SDIO-SPI-Rpi-PICO library from Carl J Kugler III in his carlk3 github repository. 

Each of the AI systems burned through eight hours, offering code and setup instructions and then bumbling through build errors, toolchain configuration changes and then fruitless debugging. I tried both methods - the library from carlk3 which had an example inside that was almost exactly what I wanted to achieve, and the Arduino IDE version, alternating which method I used with the next AI tool.

STOPPED USING THE AI TOOLS AND DID IT MYSELF

Since the AI systems appeared to simply be conducting web searches and scanning posts and documents they found, but failing to understand what was occurring enough to properly advise or debug, I dropped the tools and did my own searches. 

I decided to work on the Arduino version leveraging Adafruit TinyUSB. It did involve looking into library code in a few places but I quickly zoomed in on what was going wrong. Within 40 minutes, which included web searches and reading of code, I had the CartInterface working properly. 

ENCLOSING CARTINTERFACE IN A PROJECT BOX AND UPDATING MY V2315CF GITHUB

I have a small plastic project box into which I installed the CartInterface board, exposing the 2x4 header socket on the face and routing the USB cable through a hole. It is now complete and ready for productive use whenever I want to transfer 2315 cartridge images between the physical IBM 1130 with its V2315CF and an IBM 1130 simulator running on a PC. 

I added the code and instructions to the V2315CF repository on github thus others who build this in order to use virtual cartridges with an IBM 1130 computer have this convenience tool.