The Adafruit Feather 32u4 Bluefruit packs Arduino compatibility, Bluetooth® Low Energy, USB, and battery charging into a slim, portable board—perfect for phone-controlled and wireless projects.
Feather is Adafruit’s lightweight development board platform, designed to be thin, portable, and ideal for battery-powered projects. The Adafruit Feather 32u4 Bluefruit combines an Arduino-compatible microcontroller with Bluetooth® Low Energy, built-in USB support, and battery charging—all on a single board that’s ready to go.
At its core is the ATmega32u4, running at 8 MHz with 3.3 V logic, the same proven setup used on the Flora. The chip includes 32 KB of flash, 2 KB of RAM, and native USB, allowing it to act not only as a USB-to-serial device but also as a USB keyboard, mouse, or MIDI device—with no external FTDI chip required. Full support is provided through the Arduino IDE.
Wireless connectivity is handled by Adafruit’s Bluefruit LE module, based on the Nordic nRF51822 chipset. Bluetooth Low Energy operates in the 2.4 GHz band and is fully supported by iOS, Android, macOS, and Windows 8+, making it an excellent choice for portable projects controlled by phones or tablets. Among Adafruit’s range of BLE-capable Feather boards, this model offers a solid balance of simplicity and flexibility.
For power, the Feather 32u4 Bluefruit includes a 3.7 V LiPo battery connector with onboard charging. The board can run directly from the micro-USB connection, automatically switching to USB power when available while charging the battery. Battery voltage is also connected through a resistor divider to an analogue pin, allowing easy monitoring of charge level. The remaining board space is used to add the Bluefruit module and two status indicator LEDs.
The Power of Bluefruit LE
Out of the box, most users will use the Nordic UART RX/TX profile, which turns the BLE link into a transparent data pipe between the Feather and an iOS or Android device. Adafruit’s Bluefruit mobile apps make it easy to get started, offering tools such as a colour picker, motion and orientation data (accelerometer, gyro, magnetometer), GPS location, and an 8-button control pad. All of this data can be sent over BLE and processed directly by the ATmega32u4.
For more advanced use, the module supports a powerful AT command set, giving you control over advertising behaviour, custom GATT services and characteristics, and access to diagnostic data such as temperature, battery voltage, RSSI, and MAC address. The Bluefruit module also supports over-the-air firmware updates, allowing new wireless features to be added without touching the main microcontroller firmware.
Additional BLE roles are supported too:
BLE HID keyboard
BLE heart rate monitor (with external pulse hardware)
UriBeacon for broadcasting URLs
Each Feather 32u4 Bluefruit comes fully assembled and tested, with headers included for soldering and breadboard use. LiPo battery and micro-USB cable are not included.
Features
ATmega32u4 @ 8MHz with 3.3V logic/power
3.3V regulator with 500mA peak current output
USB native support, comes with USB bootloader and serial port debugging
You also get tons of pins - 20 GPIO pins
Hardware Serial, hardware I2C, hardware SPI support
7 x PWM pins
10 x analogue inputs
Built in 100mA lipoly charger with charging status indicator LED
Pin #13 red LED for general purpose blinking
Power/enable pin
4 mounting holes
Reset button
Specifications
Measurements: 51mm x 23mm x 8mm without headers
Weight - 5.7 grams
Revision History
As of July 9th, 2024 – We've updated this PCB with Adafruit Pinguin to make a lovely and legible silkscreen - you may get the new PCB or the older version with vector fonts - both are identical other than the fancy silkscreen.
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