M5Stack CardKB2 Keyboard Unit

The M5Stack Unit CardKB2 is a compact, card-sized keyboard module designed for portable input and embedded applications.

It features 42 keys in a lightweight form factor, making it suitable for on-the-go use or integration into custom hardware projects. The unit is powered by an ESP32-C61HF4 microcontroller with built-in 2.4GHz Wi-Fi 6, enabling both wired and wireless communication options.

Pre-installed firmware supports four communication modes - I2C, UART, BLE HID, and ESP-NOW - allowing it to be used in a wide range of setups, from direct microcontroller input to wireless control interfaces. The board includes an HY2.0-4P expansion connector for easy integration with compatible systems, along with a USB-C port for power and firmware updates.

Additional features include an RGB LED for status indication, dedicated Reset and Boot buttons, and built-in input overvoltage protection to help safeguard the device during use.

Features

• Powered by ESP32-C61HF4 with Wi-Fi 6 / BLE wireless communication support
• Full keyboard input with support for multiple key combinations (single press, Sym, Fn)
• Onboard RGB LED (XL-1615RGBC-RF) for keyboard status indication
• Power Supply:
  • USB Type-C
  • DC 5V

Specifications

SoC	ESP32-C61HF4 @ RISC-V 32-bit single-core, 120 MHz
Flash	4MB
Wi-Fi	2.4 GHz Wi-Fi 6
Keys	42-key keyboard, 1x Reset button, 1x Boot button
USB Type-C	Power supply / firmware flashing, default firmware log output: 115200bps @ 8N1
RGB LED	1x RGB LED
Expansion Interface	1x HY2.0-4P
Standby Power	[email protected] (under Grove interface power supply conditions)
Product Size	84.7 x 54.3 x 1.0mm
Product Weight	22.4g

Resources

• Product Documentation

Package Contents

• 1x M5Stack CardKB2 Keyboard Unit (ESP32-C61)
• 1x HY2.0-4P Grove Cable (20cm)