Chain Key

SKU:U206

Description

Chain Key is a single-button input node in the M5Stack Chain series. The button adopts a hot-swappable mechanical keyboard design with a blue tactile switch and integrates a programmable RGB LED. It is suitable for human-machine interaction and smart home control scenarios.

Chain Key integrates an STM32G031G8U6 core MCU and uses a UART serial cascading communication protocol. Through two HY2.0-4P expansion interfaces, it can connect more Chain series devices, enabling more complex and interactive applications.

Features

M5Stack Chain series
Single button input
STM32G031G8U6 core MCU
Hot-swappable mechanical keyboard blue switch
2x RGB LED
Uses UART cascading communication protocol
2x HY2.0-4P expansion interfaces to extend Chain series devices

Includes

1 x Chain Key
1 x Chain Bridge
1 x Keycap Sticker

Applications

Smart home control
Human-machine interaction

Specifications

Specification	Parameter
MCU	STM32G031G8U6
Input Power	DC 5V
Communication Method	UART 115200bps@8N1
Interface Spec	2x HY2.0-4P
RGB LED	2x WS2812B
Working Power Consumption	28.24mA
Working Temperature	0 ~ 40°C
Product Size	23.9 x 23.9 x 34.4mm
Product Weight	9.1g
Package Size	138.0 x 93.0 x 26.0mm
Gross Weight	14.4g

Learn

Use the Chain Bridge connector to connect the main controller Chain DualKey and various Chain series input devices. Pay attention to the direction when connecting — the triangle arrow should point outward from the main controller Chain DualKey, as shown below:

Schematics

Chain Key Schematics PDF

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PinMap

RGB LED

STM32G031	PA8
WS2812C	RGB

Button

STM32G031	PB0
Button	Input

UART

STM32G031	PB6	PB7	PA2	PA3
UART1	TXD1	RXD1
UART2			TXD2	RXD2

Model Size

Chain Key Model Size PDF