Chain Dual Key with ESP32-S3

The M5Stack Chain Dual Key is a dual-key ESP32-S3 board with hot-swappable switches, RGB LEDs, USB/BLE HID support and expansion ports — ideal for macro keyboards, smart home control and custom input projects.

The M5Stack Chain Dual Key is a programmable dual-key input development board built around the ESP32-S3FN8 main controller. It features two hot-swappable blue-switch mechanical keys and two programmable RGB LEDs on the front, giving responsive tactile and visual feedback. A built-in 350mAh lithium battery, paired with a low-power design, provides solid battery life. The board ships with Chain macro keyboard firmware and supports both USB and BLE connections, allowing it to function as a HID input device. After powering it on, you can connect to its AP hotspot and use the built-in web interface to configure HID mappings for the device itself or for expansion nodes, enabling a wide range of custom control functions. As part of the M5Stack Chain series, the Dual Key includes two HY2.0-4P expansion ports, supporting lateral expansion with additional sensors or modules. With the ESP32-S3’s built-in USB-OTG capability, it’s well suited for smart home control, keyboard peripherals, macro keyboards and other interactive projects.

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Features

* ESP32-S3FN8 main control chip

* Built-in 350mAh lithium battery

* 2 programmable RGB LEDs

* 2 hot-swappable blue switch keys

* M5Stack Chain series expandable design

* LEGO-compatible holes on the back

* Lanyard design

Specifications

SoC ESP32-S3FN8 @ Dual-core Xtensa LX7 processor, with a main frequency up to 240MHz

Flash 8MB

Power Input USB: DC 5V

Battery 350mAh lithium battery

RGB LED 2x WS2812B

Operating Temp 0 ~ 40°C

Standby Current Power-off mode (VBAT): DC 4.2V@8.97uA Deep sleep mode (VBAT): DC 4.2V@107.64uA USB 5V power (no battery): DC 5V@41.7mA

Product Size 47.9 x 34.3 x 23.9mm

Product Weight 23.7g

Resources

* Documents and schematics

Package Contents

* 1x Chain Dual Key

* 1x Keycap Sticker