CardputerZero IR-Chat

Runtime-only infrared chat for M5Stack CardputerZero.

Features

• Send and receive messages with a compact custom 38 kHz raw IR protocol
• Keep up to 64 messages in memory for the current session only
• Accept messages up to 23 printable ASCII bytes
• Discover receiver and transmitter nodes by LIRC capability instead of device number
• Use a loopback mock backend for SDL desktop development

IR requires line of sight. This protocol is specific to IR Chat and is not an infrared remote-control protocol.

Dependencies

Fetch lvgl, spdlog, and smooth_ui_toolkit into dependencies/:

./bootstrap.sh

Device builds use the Linux kernel LIRC character-device API directly and do not require a userspace LIRC library. The receiver must support LIRC_CAN_REC_MODE2, and the transmitter must support LIRC_CAN_SEND_PULSE.

Build

SDL desktop build:

cmake -S . -B build/sdl -DIR_CHAT_USE_SDL=ON
cmake --build build/sdl -j8
IR_CHAT_SDL_ZOOM=2 ./dist/M5CardputerZero-IR-Chat

CardputerZero cross-build from x86 Linux:

cmake -S . -B build/cp0 \
  -DIR_CHAT_USE_SDL=OFF \
  -DCMAKE_TOOLCHAIN_FILE=cmake/aarch64-linux-gnu.cmake
cmake --build build/cp0 -j8

The output binary is dist/M5CardputerZero-IR-Chat.

Usage

• Z/C or Left/Right: switch between Messages and IR Info
• F/X or Up/Down: scroll messages
• Enter or a printable key: open the message editor
• Enter: send; Esc: cancel, go back, or exit
• Backspace/Delete and Left/Right: edit the draft
• R or Enter on IR Info: retry initialization after an error

Hardware

By default, the device build scans rc-core/LIRC nodes and selects RX and TX by capability. These strict overrides are available when automatic discovery is not appropriate:

• IR_CHAT_LIRC_RX_DEVICE: receiver /dev/lirc* path
• IR_CHAT_LIRC_TX_DEVICE: transmitter /dev/lirc* path
• IR_CHAT_LIRC_RX_RC: receiver /sys/class/rc/rc* path
• IR_CHAT_LIRC_TX_RC: transmitter /sys/class/rc/rc* path

An override fails initialization when its node is missing or does not advertise the required capability.

Package

Build the CardputerZero arm64 APPLaunch package natively or with the GNU AArch64 cross-toolchain:

./packaging/deb/package_deb.sh

The generated package is written to dist/:

dist/m5cardputerzero-ir-chat_<version>_m5stack1_arm64.deb