DFRobot Beetle CM-32U4
Ultra-compact Arduino Leonardo-compatible microcontroller board with ATmega32U4, integrated lithium battery charging, and native USB in a tiny 22x20.5mm form factor.
$8.90
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Specifications
Components
Microchip ATmega32U4 running at 16MHz with 32KB flash, 2.5KB SRAM, 1KB EEPROM, native USB 2.0 Full-speed device, 12-channel 10-bit ADC, and JTAG debug interface.
Linear lithium battery charger with programmable charge current of 200-600mA and thermal regulation for safe LiPo charging.
Bus Interfaces
GPIO Map
Overview
The DFRobot Beetle CM-32U4 is an upgraded version of the original Beetle board, packing an ATmega32U4 microcontroller with integrated lithium battery charge management into a remarkably small 22x20.5mm footprint. Fully compatible with Arduino Leonardo, it can be programmed directly from the Arduino IDE without any additional drivers or board packages.
Despite its tiny size, the Beetle CM-32U4 exposes the most commonly used communication interfaces including I2C, SPI, UART, two analog inputs, and two digital I/O pins. The onboard TP4056X charging IC supports 200-600mA charge current for LiPo batteries, making it ideal for battery-powered portable projects.
The board's coin-sized form factor and native USB capability make it particularly well-suited for e-textiles, wearable electronics, USB HID devices like custom keyboards and macro pads, and any project where space is at a premium. Three flexible power options — USB, battery pack via BAT pin, or 5V external via VIN — give builders maximum flexibility for deployment in tight spaces.
Use Cases
4USB HID Device
Implementing a USB Human Interface Device such as a keyboard, mouse, game controller, or MIDI device using native USB support.
E-Textiles
Electronic textiles integrate circuits and microcontrollers into fabric for smart clothing, wearable sensors, and interactive garments.
Compact IoT Node
Ultra-small microcontroller boards for embedding into tight spaces in IoT projects, props, cosplay, and miniature builds.
Wearable
Body-worn computing devices including smartwatches, fitness bands, and health monitors.
Resources
Where to Buy
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