Circuit Playground Bluefruit

Overview

The Circuit Playground Bluefruit is Adafruit's most feature-packed entry-level learning board, combining a rich onboard sensor suite with Bluetooth Low Energy wireless connectivity in a circular form factor designed for beginners and educators. Built around the Nordic nRF52840 ARM Cortex-M4F running at 64MHz, it provides 1MB of Flash and 256KB of RAM alongside a dedicated 2MB SPI Flash chip for program and file storage.

The board's circular design places all components and I/O pads around the perimeter, making it instantly recognizable and easy to use with alligator clips. Ten mini NeoPixel RGB LEDs form a ring around the edge and are individually addressable. Eight large alligator-clip pads provide GPIO, analog input, PWM, I2C, and UART access without requiring soldering. A built-in MEMS microphone, phototransistor light sensor (capable of color and pulse sensing), LIS3DH triple-axis accelerometer, and thermistor round out the sensor suite.

Bluetooth Low Energy via the nRF52840's built-in radio enables wireless communication with smartphones, computers, and other BLE devices using Adafruit's Bluefruit libraries. A mini Class-D speaker amplifier drives the on-board 7.5mm speaker for tones, beeps, and simple audio. Power options include Micro-USB, a 3×AAA battery pack connector, or a LiPo battery.

The board is fully supported by CircuitPython, Microsoft MakeCode for Circuit Playground, and the Arduino IDE with the nRF52 board package. It ships with the UF2 bootloader pre-loaded, enabling drag-and-drop firmware updates without any special tools.