PitaRFID

Software

Linux OS (Raspbian in my case)
Python 3
tcpser
sio2bsd
PitaRFID disk driver
Bobterm

Hardware

1x 3 1/2 floppy disk drive
1x Raspberry Pi 2B+ or better (even things like a Zero W count as better)
1x (minimum three channels) 3.3-5V bidirectional logic level shifter
1x 1N5817 or 1N4004 diode
1x RC522-NFC tag reader
1x PCB for SIO port
13x pins
1x MicroUSB male to USB-C female adapter
Asst. M2/M3 screws
Asst. wire
Several 3 1/2 inch floppy disks
Several NFC NTAG 213 stickers

3d Prints

1x Bottom of case (Pitarfid.scad)
1x Top of case
1x Front of case
1x SIO port bracket
1x SIO port

PitaRFID at a glance

This is a project that aims to extend the useful lifespan of the Atari 800XL computer by creating a non-destructive custom peripheral that can emulate a floppy drive or Hayes-compatible serial modem.

This is accomplished via the GPIO pins on a Raspberry Pi with a WiFi dongle with a 3d-printed SIO port, along with the use of the sio2bsd and tcpser programs.

The system is controlled via a custom Python “driver” program that uses an RC522 NFC module to read the UIDs of NFC-tagged “floppy disks” (either original disks or 3d-printed replicas) when they’re inserted into a casing designed to look like a scale-model Atari 1050 disk drive.

Current Status (February 3, 2024)

Hardware

Trying to decide on adding a rocker switch to the front where the drive’s original power toggle would be. Tempted to put in a momentary two-state rocker switch and then have one side be “restart the process, as something has gone wrong” and the other be “signal the Pi to do a graceful shutdown”.

I also still need to wire an LED in behind the LED window on the disk drive, so it can give the status of the “drive”.

Software

Tracked down the unfortunate glitch that was freezing the serial modem emulation. In the process of doing so, I massively overhauled debugging (as in, it has it now) and signal handling code (as in, it has it now). The code is subtantially more (okay, ‘at all’) stable now. I’m going to spend the next couple hours doing some very enjoyable refactoring. Yes. Yes, I am a nerd, yes.

Infrastructure

I need to rejig the internal components by moving the Pi about a centimeter over to the right. Once that’s done I need to design, and then print, the front faceplate prototype, then I can print the final design in the cream-white plastic for the main body and print the faceplate in black while I agonize over the idea of buying a dark brown for “proper” printing.