Nordic nRF52840 BLE Core Module

What is the RAK3401 WisBlock Core BLE Module?

The WisBlock RAK3401 BLE module is built around the Nordic nRF52840 for applications that need Bluetooth Low Energy connectivity without built-in LoRa® or LoRaWAN®. As a BLE-focused alternative to the RAK4631, it is well suited for battery- and solar-powered IoT devices where low power consumption and reliable wireless performance matter.

Powered by the ARM Cortex-M4F-based nRF52840, the RAK3401 balances processing capability with energy efficiency for remote sensors, BLE end nodes, and other embedded IoT designs. It also includes a temperature-controlled crystal oscillator for stable timing and provides interfaces such as UART, I2C, SPI, ADC, USB, and GPIO for easy integration with WisBlock modules, sensors, and expansion boards. For designs that need external LoRa capability, the RAK3401 can also be used with the RAK13302 1W transceiver module on the RAK19007 Base Board. Development is supported in Arduino IDE and PlatformIO for VS Code using our Arduino BSP, helping speed up prototyping and development. 

Notes: This module only supports Bluetooth Low Energy connectivity. If you need LoRa or LoRaWAN communication, please check our RAK4631 WisBlock Core module. It combines the nRF52840 MCU with a Semtech SX1262 transceiver module based on LoRa technology.

Who Is the RAK3401 BLE Core Module Designed For?

The RAK3401 BLE Core Module is designed for engineers, system integrators, and product teams building Bluetooth Low Energy IoT nodes. It suits developers who need a compact MCU for sensor data collection, local wireless communication, and low-power operation. The module fits projects that rely on modular hardware expansion through the WisBlock ecosystem and require predictable behavior in long-term deployments. 

It is also well-suited for teams that need a reusable hardware platform where sensor, power, and interface modules can be standardized across multiple BLE products using the WisBlock ecosystem. This makes it a reliable BLE IoT node with nRF52840 for modular deployments. Typical use cases include modular BLE IoT nodes with nRF52840 used in agriculture, industrial monitoring, and environmental sensing.

Why You Need RAK3401 WisBlock BLE Module?

The nRF52840 BLE Core Module delivers reliable BLE connectivity and flexible integration, providing outcomes such as extended battery life and adaptable sensor expansion for IoT deployments.

Why it's useful

• Energy Efficiency: Reduces power consumption for long-term field deployment.
• Flexible Integration: Connects easily with multiple sensor types for versatile applications.
• Remote Monitoring: Supports data collection in locations without wired connectivity.
• Scalable Prototyping: Allows rapid testing and iteration for development projects.

Key Features of the WisBlock Nordic nRF52840 BLE Core Module

• Processor Architecture: ARM Cortex-M4F
• Memory: 1MB Flash / 348KB SRAM
• I/O Interfaces: UART, I2C, SPI, ADC, GPIO

Comparison: RAK3401 vs Other nRF52840 BLE Modules

Compared with generic Nordic BLE development modules, the RAK3401 focuses on deployment-ready modularity rather than evaluation-only use.

Use Case Examples for BLE IoT Applications 

This module provides precise BLE communication for IoT projects, enabling data collection and sensor integration across remote or distributed environments.

Use Case #1: Smart Agriculture Soil Monitoring

A distributed soil monitoring system deployed BLE 5.0 sensors using the RAK3401 nRF52840 module across 120 nodes per field. Each node advertised data every 10 seconds at 0 dBm, then entered deep sleep. Nodes ran on AA lithium batteries supplemented by small solar panels, achieving 6–9 months of operation.

Use Case #2: Industrial Asset Tracking

Battery-powered asset tags built on the RAK3401 WisBlock BLE module transmitted beacons at 5-second advertising intervals using BLE extended advertising. The system supported 200+ nodes per zone, with RSSI-based filtering validated during peak activity to maintain reliable updates.

WisBlock Ecosystem Compatibility & Expansion

The RAK3401 is not a standalone BLE module. It is designed as part of the WisBlock modular hardware ecosystem. Unlike generic nRF52840 modules that require custom carrier boards and wiring, the RAK3401 interfaces directly with WisBlock Base Boards that standardize power distribution, signal routing, and mechanical mounting.

WisBlock expansion modules cover sensors, power management, interfaces, and connectivity, allowing engineers to assemble complete BLE IoT nodes without redesigning hardware for each use case. Sensor modules can be swapped or added without modifying hardware interfaces, while power modules support battery, and solar-assisted designs using the same core module.

This ecosystem approach reduces integration risk, shortens development cycles, and enables hardware reuse across multiple product variants. Compared to adapter-based ecosystems, WisBlock provides a production-oriented modular architecture suitable for both prototyping and deployment.

Why the WisBlock Ecosystem Matters for BLE IoT Design?

Many BLE platforms are built mainly for prototyping, often relying on add-on boards or cables that are not ideal for long-term deployment. The WisBlock ecosystem is different. It uses a modular, stackable design with consistent electrical and mechanical interfaces, making it more practical for scalable BLE IoT products.

With WisBlock:

• The RAK3401 core module handles processing
• Base Boards manage power, charging, and mounting
• Sensor and interface modules connect through standardized connectors

• Designers can avoid jumper wires, custom PCBs, and repeated hardware redesign

This modular approach helps support:

• Scalable node designs
• Higher-density deployments
• More consistent manufacturing results

• Faster transition from prototype to production

Why Choose the RAK3401 WisBlock BLE Core Module?

The RAK3401 is a BLE-only variant of RAK4631. It serves as a BLE-only variant of the RAK4631 WisBlock Core for projects that prioritize power efficiency over long-range RF. This BLE-only nRF52840 core module is designed for low-power, long-term IoT deployments where LoRa connectivity is not required. It offers the same MCU foundation as the RAK4631 but removes the integrated LoRa transceiver to reduce power consumption and system complexity.

With a TCXO for stable timing, multiple digital interfaces, and full compatibility with the WisBlock modular ecosystem, it enables developers to build battery and/or solar-powered BLE sensor nodes that can be easily expanded or adapted as requirements change. This BLE MCU module with TCXO stability ensures reliable timing for synchronized sensing and wireless communication.

Compared to development boards or bare OEM modules, the RAK3401 balances production readiness, modularity, and developer accessibility.

What’s in the Box

• 1 pc RAK3401 WisBlock Core module
• 1 pc WiFi/BLE PCB antenna (MHF1 Connector)
• 1 set Screw

How to Get Started with RAK3401

• Overview of RAK3401 WisBlock BLE Module
• Quick Start Guide of RAK3401 WisBlock BLE Module
• Datasheet of RAK3401 WisBlock BLE Module