Resources:
Documents
50-Key QWERTY I2C Keyboard Unit with ATmega8A and RGB Status LED
The M5Stack U035-B Unit CardKB v1.1 is a compact, card-sized QWERTY keyboard designed to add full text and command input to M5Stack controllers and embedded projects. It uses an ATmega8A microcontroller to scan and encode the 50-key PCB matrix and sends key values to the host through an I2C interface. Its compact 88 × 54 mm form factor makes it suitable for portable terminals, command interfaces, text-entry devices, and interactive IoT applications.
The keyboard supports standard single-key input along with Shift, Sym, and Fn combinations for uppercase characters, symbols, and customizable functions. Shift and Sym modes can also be locked by double-clicking the corresponding key. An onboard RGB LED provides keyboard-status indication, while the HY2.0-4P Grove interface supplies power and I2C connectivity through a single cable. CardKB v1.1 supports UIFlow1, UiFlow2, and Arduino development for integration with compatible M5Stack controllers.
Key Features
- ATmega8A keyboard-encoding microcontroller
- 50-key QWERTY PCB matrix keyboard
- Card-sized compact design
- I2C communication interface
- Default I2C address: 0x5F
- Supports standard lowercase character input
- Shift + key for uppercase characters
- Sym + key for secondary symbols
- Fn + key for customizable third-level functions
- Shift lock supported through double-click
- Sym lock supported through double-click
- 1 × onboard RGB status LED
- HY2.0-4P Grove interface
- 5V power through Grove connection
- Suitable as a keyboard peripheral for M5Stack controllers
- Supports UiFlow1, UiFlow2, and Arduino development
Applications
- M5Stack keyboard peripheral
- Portable text-entry terminals
- IoT control interfaces
- Embedded command consoles
- DIY handheld devices
- Menu-navigation systems
- Smart home controllers
- Educational programming projects
- Embedded data-entry applications
- Custom user-interface projects
- Microcontroller input systems
- Portable control panels
Model Size
Package Includes:
- 1 x Unit CardKB v1.1
- 1 x HY2.0-4P Grove connection cable (20cm)
