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RAK4631 WisBlock Build Guide

Overview

The RAK WisBlock system is a modular hardware platform built around small snap-together modules. For LoRa mesh applications, the core build consists of:

  • RAK4631 Core Module —- Contains a Nordic Semiconductor nRF52840 microcontroller and a Semtech SX1262 LoRa radio on a compact daughter board.
  • RAK19007 Base Board —- The main carrier board with USB, battery connector, sensor slots, and IO headers. The RAK4631 plugs into the core slot.

Optional expansion modules (GPS, sensors, displays) plug into the modular slots on the base board without soldering.

Why Choose RAK WisBlock Over ESP32-Based Boards?

The nRF52840 microcontroller used in the RAK4631 has dramatically lower power consumption than the ESP32:

  • nRF52840 active current: 8–8 - 12 mA (typical mesh node operation)
  • ESP32 active current: 40–40 - 80 mA (typical mesh node operation)
  • nRF52840 sleep current: ~3 µA

This difference makes the RAK4631 the preferred choice for:

  • Solar-powered remote repeaters where power budget is tight
  • Battery-only deployments requiring multi-week operation
  • Installations where charging infrastructure is unavailable or unreliable

The trade-off is that RAK WisBlock is more expensive than Heltec or T-Beam, and the modular ecosystem can be initially confusing.

Bill of Materials

  • RAK19007 Base Board (or RAK5005-O for older builds)
  • RAK4631 Core Module (nRF52840 + SX1262)
  • RAK1910 GPS Module —- optional, plugs into Slot A on the base board; uses u-blox MAX-7Q GPS
  • LiPo battery with appropriate connector (RAK19007 uses JST 1.25mm or 2.0mm depending on version —- check your specific board)
  • SMA antenna matched to your frequency band (868 or 915 MHz)
  • Optional: RAKBox-B2 weatherproof enclosure, or any IP65+ electronics enclosure

Build Assembly

One of the significant advantages of WisBlock is that a basic build requires no soldering:

  1. Align the RAK4631 core module with the core slot on the RAK19007 base board (the slot is keyed —- it only fits one way).
  2. Press down firmly until the module clicks into place. The board-to-board connectors are friction-fit.
  3. If using the RAK1910 GPS module, slot it into Slot A (the larger expansion slot) on the base board in the same way.
  4. Connect the antenna to the SMA or IPEX connector on the RAK4631. For permanent outdoor installs, use an SMA pigtail routed to an external bulkhead connector.
  5. Connect the LiPo battery to the battery connector on the RAK19007.

The board is now physically assembled and ready for firmware flashing.

Flashing Firmware

Meshtastic

The RAK4631 is supported by the Meshtastic web flasher:

  1. Connect the RAK19007 base board via USB to a computer running Chrome or Edge.
  2. Navigate to flasher.meshtastic.org.
  3. Select RAK WisBlock RAK4631 from the device list.
  4. Click Flash and wait for completion.

MeshCore

MeshCore firmware for RAK4631 is available as a UF2 file for drag-and-drop flashing:

  1. Download the latest RAK4631 firmware from github.com/meshcore-dev/MeshCore/releases. Select the correct UF2 file for your role (Repeater, Client, etc.).
  2. Double-press the reset button on the RAK4631 to enter bootloader mode. The board will appear as a USB mass storage device named RAK4631 (or similar).
  3. Drag and drop the UF2 file onto the mounted drive. The board will flash and reboot automatically.
  4. Alternatively, flash using the Arduino IDE with the appropriate BSP (Board Support Package) for nRF52840.

Power & Battery Notes

  • The RAK19007 includes an onboard LiPo charger suitable for standard Li-ion/LiPo cells.
  • For LiFePO4 batteries (preferred for outdoor/solar installs due to better temperature performance and cycle life), the charge voltage must be adjusted. The RAK5005-O base board allows charge voltage configuration via a solder jumper or register; consult the RAK documentation for your specific base board version before connecting LiFePO4 cells.
  • The nRF52840 supports aggressive sleep modes. Ensure your firmware is configured to use deep sleep between transmit/receive windows for maximum battery life.

Enclosure Options

  • RAKBox-B2 —- RAK's own weatherproof enclosure, designed to fit the WisBlock base boards with mounting points. Available with and without a solar panel lid option. Rated IP67.
  • Any IP65 or better electronics enclosure that fits your base board dimensions. The RAK19007 is approximately 30×60mm (the core module adds some height), so a 100×68×40mm or larger box works comfortably.
  • Cable management is simpler than ESP32 boards due to the lower current draw —- thinner wiring and smaller connectors are sufficient.
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