A ROM hack, and matching controller, to add rotary controls to the Neo Geo game Puzzle Bobble

The ROM hack is complete. It...

• gives rotary controls to all gameplay
• rotary input on high score name entry screen
• how to play screen has a spinner instead of a joystick
• each player can hold start for about 1.5 seconds to toggle between joystick and rotary controls. Useful if say playing a two player game and only have one rotary controller.

The complete patch is at src/patches/rotary-bobble.json

I have built a rough, but working, prototype using an Arduino Nano.

It uses transistors to control RLDU, B, C and D. It has normal push buttons for A, Select, Start.

I also had a prototype using a Raspberry Pi Pico, but always had a little bit of noise in the Pico's analog readings, causing a bit of jitter during gameplay. The Nano has no jitter and provides perfect controls.

For more info, check the src/pico and src/arduino folders.

IPS patches are available in releases

1. unzip pbobblen.zip
2. patch d96-02.c5 with pbobblen.d96-02.c5.ips using an IPS patcher
3. patch d96-03.c6 with pbobblen.d96-03.c6.ips using an IPS patcher
4. patch d96-07.ep1 with pbobblen.d96-07.ep1.ips using an IPS patcher
5. Make sure the three patched files keep the original name of the file they patched (overwrite it)
6. zip the files back up into pbobblen.zip

NOTE: MAME will notice the ROM is different and not launch it from the UI. You must launch it from the command line if using MAME

• Controller

  • build a working prototype
  • circuit can likely be improved, just winged it...
  • resolve the potentiometer noise issue, possibly with an LM4040?
  • Simple input mode to handle things like NeoSD's menu
  • Figure out a good power solution for the Arduino
  • Instructions on how to create a controller

• ROM Hack

  • single player rotary controls during main gameplay
  • High score entry using rotary controls
  • Allow player two to use rotary controls during a single player game (ie start a game with p2 instead of p1)
  • Rotary controls for both players during a two player match (versus)
  • Add a tagline to the title screen to indicate this is the rotary version
  • Allow toggling rotary by holding start for a couple seconds
  • Change the how to play to show rotary controls
  • maybe a website that easily allows applying the hack?

The 68k assember, clownassembler, was copied into clownassembler/ from https://github.com/Clownacy/clownassembler, it needs to be built with cd clownassembler && make. This is needed for creating patches.

only tested on x64 Ubuntu 22. You will need a recent version of Node, I am using 18.18.2

Set the env variable MAME_ROM_DIR to where you store your roms for MAME.

• yarn install
• copy an untouched pbobblen.zip, that is intended for MAME, into the root directory of the repo
  • all zips are in gitignore, so the rom won't end up in the repo
• run ts-node src/patchRom/main.ts src/patches/rotary-bobble.json

rotary-bobble.json is the main patch, and applies all changes. The patches in patches/individual can be applied instead to just do parts. They should be self explanatory from the file name and the description at the top of each patch.

Once patched, it will run in MAME if you start it on the command line. You can also run yarn to-neosd to create a .neo file. This requires neosdconv. I would prefer to use TerraOnion's NeoBuilder, but I've not gotten it to work properly.