XIAO nRF52840 Sense Pre-Soldered Bluetooth 5.4 TinyML Board 64MHz Cortex-M4F 6-Axis IMU PDM Mic NFC 1MB Flash

XIAO nRF52840 Sense Pre-Soldered TinyML Development Board

The XIAO nRF52840 Sense is a compact, low-power wireless microcontroller development board built around the Nordic nRF52840 SoC. It combines a 64MHz Arm Cortex-M4 processor with FPU, Bluetooth Low Energy 5.4, Bluetooth Mesh, NFC, a six-axis IMU and a PDM digital microphone. Pre-soldered headers and a 21 × 17.8mm footprint make it suitable for wearable electronics, motion detection, audio recognition, TinyML and battery-powered IoT applications.

Technical Specifications

• Product model: XIAO nRF52840 Sense
• Version: Pre-soldered
• Microcontroller: Nordic nRF52840 SoC
• Processor architecture: 32-bit Arm Cortex-M4 with FPU
• Maximum clock frequency: 64MHz
• Internal Flash memory: 1MB
• RAM: 256KB
• Additional onboard memory: 2MB QSPI Flash
• Wireless connectivity: Bluetooth Low Energy 5.4
• Mesh connectivity: Bluetooth Mesh
• Wireless antenna: Onboard 2.4GHz antenna
• NFC: Supported through dedicated NFC pins
• Motion sensor: LSM6DS3TR-C six-axis IMU
• IMU functions: Three-axis accelerometer and three-axis gyroscope
• Audio sensor: Onboard PDM digital microphone
• UART interfaces: 1
• I²C interfaces: 1
• SPI interfaces: 1
• NFC interfaces: 1
• Debug interface: SWD
• Digital I/O: 11 PWM-capable GPIOs
• Analog inputs: 6 ADC channels
• USB connector: USB Type-C
• Onboard control: RESET button
• Onboard indicators: Three-in-one user LED and charging LED
• Logic voltage: 3.3V
• USB/VIN input: 5V DC
• Battery input: Compatible single-cell 3.7V lithium battery
• Battery-charging IC: BQ25101
• Selectable charging current: 50mA or 100mA
• Standby consumption: Less than 5μA under specified conditions
• Programming compatibility: Arduino, CircuitPython and MicroPython
• Dimensions: 21 × 17.8mm
• Header configuration: Pre-soldered
• Component layout: Single-sided surface-mount design

Nordic nRF52840 Processing

The Nordic nRF52840 integrates a 32-bit Arm Cortex-M4 processor operating at up to 64MHz. Its floating-point unit, 1MB internal Flash and 256KB RAM provide resources for Bluetooth protocol stacks, sensor processing, embedded control and compact machine-learning models.

Six-Axis Motion Sensing

The onboard LSM6DS3TR-C IMU combines a three-axis accelerometer and three-axis gyroscope. It can collect movement and orientation data for gesture recognition, activity tracking, equipment monitoring, wearable controllers and TinyML classification applications.

PDM Digital Microphone

The integrated PDM digital microphone captures audio data without requiring an external microphone module. It supports sound detection, voice-triggered controls, audio classification and other embedded machine-learning experiments.

Bluetooth LE, Bluetooth Mesh and NFC

Bluetooth Low Energy connectivity and the onboard 2.4GHz antenna support communication with smartphones, computers, gateways and compatible peripherals. Bluetooth Mesh enables distributed wireless networks, while dedicated NFC pins support connection to a compatible external NFC antenna.

GPIO and Peripheral Expansion

The board provides 11 PWM-capable GPIOs, six ADC channels, UART, I²C and SPI interfaces for external sensors, displays, actuators and communication hardware. The SWD interface supports compatible programming and hardware-debugging equipment.

Low-Power Battery Operation

The board accepts 5V power through USB Type-C or can operate from a compatible single-cell rechargeable lithium battery. Its BQ25101 charging circuit provides selectable 50mA or 100mA charging, while standby consumption below 5μA under specified conditions supports intermittently active portable devices.

Compact Pre-Soldered Construction

The 21 × 17.8mm board is supplied with pre-installed headers for immediate breadboard and jumper-wire connection. Its compact footprint and single-sided component layout simplify integration into wearable electronics, miniature sensor nodes and custom carrier boards.

Typical Applications

• TinyML motion and audio classification
• Gesture-recognition devices
• Voice-activated embedded controls
• Wearable electronics and activity trackers
• Bluetooth Low Energy sensors
• Bluetooth Mesh networks
• NFC-enabled embedded devices
• Battery-powered IoT nodes
• Robotics and motion monitoring
• Electronics education and rapid prototyping