XIAO nRF52840 Sense Data Logger

Languages: English | 日本語

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🚀 Overview

A dual-component sensor data logging system for XIAO nRF52840 Sense microcontroller that collects IMU (accelerometer/gyroscope) and PDM microphone data, providing real-time web oscilloscope visualization or CSV data export over BLE and USB Serial.

System Architecture

• Sender: C++/Arduino firmware running on XIAO nRF52840 Sense
• Receiver: Python BLE client with web oscilloscope interface and CSV export

📦 Components

Sender (Firmware)

• Hardware: XIAO nRF52840 Sense with LSM6DS3 IMU and PDM microphone
• Framework: Arduino + PlatformIO
• Output: CSV data via BLE Nordic UART Service and USB Serial
• Data Rate: ~100Hz via Serial, ~25Hz via BLE

Receiver (Python Tool)

• Platform: Python 3.12+ with uv package manager
• Default Mode: Interactive web oscilloscope with real-time sensor plots
• CSV Mode: Command-line data export with filtering options
• Dependencies: bleak (BLE), dash (web UI), plotly (visualization), pandas (data)

🚀 Quick Start

Prerequisites

• Hardware: XIAO nRF52840 Sense board
• Software:
  • PlatformIO Core (firmware development)
  • Python 3.12+ with uv (data reception)
  • Bluetooth adapter (for BLE reception)

1. Firmware Setup

Navigate to sender directory:

cd sender/

Build firmware:

pio run

Upload firmware

pio run -t upload

Monitor serial output:

pio device monitor -b 115200

2. Data Reception

Web Oscilloscope (Default)

Navigate to receiver directory:

cd receiver/

Install dependencies:

uv sync

Start web interface:

uv run xiao-nrf52840-sense-receiver

📊 Access the oscilloscope: Open http://localhost:8050 in your web browser

The web interface provides:

• Real-time sensor plots: Accelerometer, gyroscope, temperature, and audio data
• Interactive controls: Pan, zoom, autoscale, and plot visibility toggles
• Recording functionality: Capture data sessions with timestamps
• Connection status: Live monitoring of BLE connection health

CSV Export Mode

Enable CSV output mode:

uv run xiao-nrf52840-sense-receiver --csv --no-header --drop-missing-audio

📊 Data Format

CSV output with 9 fields:

millis,ax,ay,az,gx,gy,gz,tempC,audioRMS

• millis: Timestamp (milliseconds since boot)
• ax,ay,az: Accelerometer (g)
• gx,gy,gz: Gyroscope (dps)
• tempC: Temperature (°C)
• audioRMS: Audio RMS value (10ms window, -1.0 for missing data)

🔧 Development

Firmware Development

See sender/README.md for detailed firmware development instructions.

Python Tool Development

See receiver/README.md for Python development guidelines and API documentation.

🎯 Use Cases

Real-time Monitoring

• Live Oscilloscope: Interactive web interface for real-time sensor visualization
• Motion Analysis: IMU data monitoring for robotics and movement studies
• Audio Monitoring: Ambient sound level tracking with accelerometer context

Data Collection & Analysis

• CSV Data Export: Long-term data logging with filtering and export options
• IoT Prototyping: Wireless sensor data collection with BLE connectivity
• Educational Projects: Sensor data analysis and signal processing studies

🛠 System Requirements

Hardware

• XIAO nRF52840 Sense board
• USB-C cable for programming and serial communication
• Computer with Bluetooth Low Energy support

Software

• Firmware: PlatformIO Core, Git
• Data Reception: Python 3.12+, uv package manager
• OS Support: Windows, macOS, Linux (BLE stack dependent)

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.