hnr26-badge-nfc

monorepo related to development/experimentation on the hack and roll nfc badge reader~

project ideas

• bus card info reader
• maimai card info reader..?! it has wifi after all... (but depends on their api hhh)
• pure c graphics manipulation on the screen per-pixel? see: https://youtu.be/xNX9H_ZkfNE

project experiments

• hello world test
• counter programme (impl. original code for UI)
• nfc reader reimplementation
• image UI
• spotify websocket thing

dumped file structure

esp32c3-dump
|- fs/             # copy of device's root dir
|- full_flash.bin  # complete copy of flash

environment setup (for interacting with device)

access micropython REPL using mpremote

uv tool install mpremote

to enter REPL on the serial device:

mpremote repl

• then CTRL + C to enter device's REPL prompt. (ends running programme and exits into REPL)
• CTRL + D to re-run previously ended programme (by soft-rebooting micropython interpreter)
• CTRL + X to exit prompt

alternatively using screen

screen /dev/ttyACM0

• then CTRL + C to enter REPL
• use CTRL + A, then K, then Y to exit screen

dumping files

using mpremote, use:

mpremote connect /dev/ttyACM0 fs cp :<file_to_dump> ./<location_in_cwd>

in this specific micropython environment, because the environment is either outdated or too minimal, the ls and cp -r commands don't work on mpremote as they rely on ilistdir() which isn't implemented.

therefore, use:

mpremote run copytree.py

then manually copy the output files one-by-one into the correct directories using the earlier cp command (yeah is scuffed)

dumping flash

put esp into bootloader mode:

• hold BOOT
• press and release RESET
• release BOOT

install esptool:

uv tool install esptool

check connection:

esptool --chip esp32c3 chip_id

find flash size (for dumping):

esptool flash_id

dump entire flash:

esptool.py read_flash 0x000000 0x400000 full_flash.bin