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The First RNode Design

This is an archived page detailing the original, first version of the RNode design. For the latest version, please see the RNode page.

An RNode is an integrated, long-range data-radio that uses raw LoRa modulation in a variety of frequency bands. You can think of it as a general-purpose LoRa-based network card for your computer or mobile device. It connects to a host via USB, UART serial, Bluetooth or WiFi. It can also be programmed for independent operation. In short: A swiss army-knife of a LoRa-based communication device.

You can turn different kinds of LoRa development boards into an RNode, build one yourself, or buy a ready-to-use version from my shop. Self-built versions, and RNodes repurposed from other LoRa dev boards will be functionally identical, but may come in many different shapes and sizes, and have different pin layouts. Most of the details on this page concern the original RNode design, but will also be applicable to any other type of RNode.

An RNode can functions as a:

RNode is controlled by a powerful ATmega1284p MCU, and is fully Arduino compatible. You can use the included firmware, or it can be programmed any way you like, either from the Arduino IDE, or using any of the available tools for AVR development. The included firmware can also be edited and compiled directly from the Arduino IDE.

For adding RNode to your Arduino environment, please see this post. For configuring an RNode, please have a look at the RNode Config Utility.


Frequency Bands

RNode can operate in the following two frequency bands:

Custom made or RNodes made from repurposed boards may be able to utilise other frquency bands depending on their transceiver setups.

Operating Modes

RNode can operate in two modes, host-controlled (default) and TNC mode:

Resources and Downloads

Examples and Learning Resources

If you want some inspiration to get started with RNode, have a look at the following examples. Most of them contain step-by-step instructions on how to do them yourself.

Pinout and Overview

Programming Interface

Using the included libraries, it's easy to use RNode in your software. Here's a Python example:

from RNode import RNodeInterface

def gotPacket(data, rnode):
    print "Received a packet: "+data

rnode = RNodeInterface(
    callback = gotPacket,
    name = "My RNode",
    port = "/dev/ttyUSB0",
    frequency = 868000000,
    bandwidth = 125000,
    txpower = 2,
    sf = 7,
    cr = 5,
    loglevel = RNodeInterface.LOG_DEBUG)

rnode.send("Hello World!")

USB and Serial Protocol

You can communicate with RNode either via the on-board USB connector, or using the serial pins on the board (labeled RX0 and TX0). RNode uses a standard FTDI USB chip, so it works out of the box without additional drivers in most operating systems.

All communications to and from the board uses KISS framing with a custom command set. RNode also does not use HDLC ports in the command byte, and as such uses the full 8 bits of the command byte is available for the actual command. Please see table below for supported commands.

Command Byte Description
Data frame 0x00 A data packet to or from the device
Frequency 0x01 Sets or queries the frequency
Bandwidth 0x02 Sets or queries the bandwidth
TX Power 0x03 Sets or queries the TX power
Spreading Factor 0x04 Sets or queries the spreading factor
Coding Rate 0x05 Sets or queries the coding rate
Radio State 0x06 Sets or queries radio state
Radio Lock 0x07 Sets or queries the radio lock
Device Detect 0x08 Probe command for device detection
Promiscuous 0x0E Sets or queries promiscuous mode
Ready 0x0F Flow control command indicating ready for TX
RX Stats 0x21 Queries received bytes
TX Stats 0x22 Queries transmitted bytes
Last RSSI 0x23 Indicates RSSI of last packet received
Blink 0x30 Blinks LEDs
Random 0x40 Queries for a random number
Firmware Version 0x50 Queries for installed firmware version
ROM Read 0x51 Read EEPROM byte
ROM Write 0x52 Write EEPROM byte
TNC Mode 0x53 Enables TNC mode
Normal Mode 0x54 Enables host-controlled mode
ROM Erase 0x59 Completely erases EEPROM
Error 0x90 Indicates an error

A few notes on the EEPROM

As a completely open device, RNode does not block you from modifying the EEPROM contents, which specifies things like radio parameters, serial number, manufacture date and similar. But please be aware that doing so might render the device inoperable or burn out the radio. Before making any modifications, please make sure to create a backup of the EEPROM.

RNode includes a cryptographic signature of the EEPROM contents, which validates all the information stored within it. You will not be able to re-create a valid signature if you erase it! Without this signature, the board will still function, but warranty will be void. If you upload your own programs or alternative firmwares to RNode, you should make sure that they don't write to the last 200 bytes of EEPROM. You can back up your EEPROM with the config utility.

How do I get it?

You can buy one from my shop, or make it yourself. Using the circuit design files, it is possible to build a fully functional RNode on a breadboard. See the following articles for more info on how to easily make your own RNodes from common boards:

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Unless otherwise noted, everything here is put into the world under a CC BY-NC-SA 4.0 license.
Feel free to share and remix, just remember the attribution.