unsigned.io

What is it?

RNode is an integrated, long-range data-radio that uses raw LoRa modulation in a variety of frequency bands. It connects to a host via USB or serial, or can be directly programmed for independent operation.

Or in short: A swiss army-knife of a LoRa-based communication device.

RNode can functions as a:

• LoRa interface for your computer (or any device with a USB or serial port)
• Packet sniffer for LoRa networks
• LoRa development board
• A LoRa-based KISS-compatible TNC
• Network adapter for RNS
• A flexible platform for experiementing with LoRa technology
• LoRaWAN support is coming in a future firmware update

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.

RNodes are now shipping, get yours from my shop

Specifications

• High-quality LoRa module with genuine Semtech SX1276 chip
• Powered by an ATmega1284p MCU clocked at 16 MHz
• 128 kilobytes of flash
• 16 kilobytes of RAM
• Large payloads with a packet MTU of 500 bytes
• Up to 17 dBm continuous TX output in 820-1020 MHz
• Up to 14 dBm continuous TX output in 410-525 MHz
• Sensitivity down to -139 dBm
• Data rates ranging from 20 bps to 21.88 kbps
• Mini-USB connector
• SMA antenna connector
• Fully programmable
• Arduino compatible
• Open source firmware and config util
• 15 general purpose IO ports available
  • All ports can be used as digital inputs or outputs
  • 5 ports can be used as analog inputs
  • An extra UART serial port is available on two of the pins
  • I2C port
  • Two PWM outputs are available
  • JTAG port available
• Operating range: -20°C to 60°C (non-condensing)
• 23.3 mA idle power consumption

Frequency Bands

RNode can operate in the following two frequency bands:

• 410 – 525 MHz
• 820 – 1020 MHz

Operating Modes

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

• When RNode is in host-controlled mode, it will stay in standby when powered on, until the host specifies frequency, bandwidth, transmit power and other required parameters. In host-controlled mode, promiscuous mode can be activated to sniff any LoRa frames.
• When RNode is in TNC mode, it will configure itself on powerup and enable the radio immediately. This mode can be enabled by using the configuration utility (the utility will guide you through the settings if you don’t specify them directly).

Resources and Downloads

• User manual
• Configuration utility
• Firmware downloads and source code
• LoRa packet sniffer program for RNode
• Programming examples
• Schematics and design files
• Adding RNode to the Arduino IDE

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.

• Super long distance SSH link
• RNode as wireless network card
• APRS over LoRa
• LoRa packet sniffing

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.