README.md

@mschaeffler/node-red-lora

Five nodes to send and receive LoRaWan messages via a gateway via the Semtech UDP protocol.

Install

$ npm install @mschaeffler/node-red-lora

Usage

By combining this five nodes, you can receive and send LoRaWan messages via a compatible gateway.

lora server

This node is a UDP server to communicate with LoRa gateways via the SEMTECH protocol.

Input

msg.	type	description
payload	object	encoded txpk object generated py lora encoder.

Outputs

tx

msg.	type	description
payload	object	received message to be processed by lora decoder.
mac	string	mac of the gateway.

stat

msg.	type	description
payload	object	statistical data from gateway.
mac	string	mac of the gateway.

Parameters

config	type	description
UDP Port	number	port at which the server receives messages from the gateway.

lora decoder

This node decodes a LoraWan message received by lora server. It also generates messages to be sent to the end node in case of

• confirmed messages: the corresponding acknowledgment
• a message for this node from the send queue (s. lora send).

By this the downlink messages can be timed to be sent in the RX1 receive window of the LoRa end node.

Input

msg.	type	description
payload	object	lora message received by lora server.

Outputs

decoded payload

msg.	type	description
topic	string	name of the end node from lora keys.
payload	object	decoded message to be further processed by lora check FC.
timeout	number	timeout, if present in lora keys for this node.

{
    "rxpk": {                    // data from lora server
        "tmst": 501680883,
        "chan": 0,
        "rfch": 1,
        "freq": 868.1,
        "stat": 1,
        "modu": "LORA",
        "datr": "SF7BW125",
        "codr": "4/5",
        "lsnr": 10.3,
        "rssi": -67,
        "size": 23,
        "data": "...",
        "time": 1643556838991
    },
    "device_address": "123456ab",
    "frame_count": 4592,
    "port": 10,
    "mtype": "Confirmed Data Up",
    "confirmed": true,           // confirmed uplink?
    "type": "FooType",           // type of the lora node from lorawan-keys
    "name": "FooBar",            // name of the lora node from lorawan-keys
    "data": [ 0, 0 ]             // payload of the lora message
}

unknown sender

msg.	type	description
payload	object	messages from unkown end nodes.

send message for encoder

msg.	type	description
payload	object	message from send queue to be encoded by lora encoder.

Parameters

config	type	description
LoRa Keys	lorawan-keys	configuration node to define the end nodes.
TX-delay	number	delay in µs for a downlink message (RECEIVE_DELAY1 in LoRa); possibly needs some tweaking.

lora encoder

This node encodes a LoraWan message.

A local filesystem context store called storeInFile is needed to store the internal data.

Input

msg.	type	description
payload	object	lora message to be sent; normally from lora decoder, send message for encoder.
framecounter	number	set frame counter default value from versions <2.0.0; this default value wil be active until Node-RED will be restarted.
framecounter	object	set frame counters with value from persistent memory.

Outputs

encoded payload

msg.	type	description
payload	object	encoded message for lora sender.

frame counters for persistence

msg.	type	description
payload	number	frame counters for the different lora nodes for persistent storage.

Parameters

config	type	description
LoRa Keys	lorawan-keys	configuration node to define the end nodes.
TX-Power	number	transmit power for the gateway.

lora check FC

This node checks the frame counter (FC) of a LoraWan message.

It recognizes this situations:

• first message received: ok
• FC 0: ok, startup of end node
• FC increased by one: ok
• FC rollover: ok
• FC increased by more then one: ok + error message missing frame
• FC the same as last valid one: duplicate message
• anything else: error merssage, LoRa message is discared

Input

msg.	type	description
topic	string	name of the end node from lora keys.
payload	object	lora message decoded by lora decoder.

Outputs

checked lora message

msg.	type	description
topic	string	name of the end node from lora keys.
payload	object	checked ok message ready for node specific payload decoder.

duplicate message

msg.	type	description
topic	string	name of the end node from lora keys.
payload	object	message in case of a reuse of the last valid farme counter value.

error message

msg.	type	description
topic	string	subject of the error message.
payload	string	error message for logging.
lora	object	lora msg that caused the error message.

counters

msg.	type	description
payload.ok	number	Number of ok messages.
payload.nok	number	Number of error messages.
payload.dup	number	Number of duplicate messages.
payload.mis	number	Number of missing messages.

lora send

This node puts a LoraWan message into the send queue. The send queue is stored in the flow context sendqueue.

Input

msg.	type	description
payload	byte array	lora payload to be sent; as an array of bytes or as a Buffer.
topic	string	name of the LoRa end node as in LoRa Keys.

Parameters

config	type	description
LoRa Keys	lorawan-keys	configuration node to define the end nodes.

lora keys

This configuration node stores data about the LoRa end nodes.

Parameters

config	type	description
LoRa-Keys	object	config data about the end nodes.

{
    <device address in lowercase hex>: {
        "nsw": "<LoRa NwkSKey>",
        "asw": "<LoRa AppSKey>",
        "type": "<Type of the node for further processing>",
        "name": "<Name of the node>",
        "timeout": <Timeout value for further processing, optional>;
    },
    "123456ab": {
        "nsw": "0123456789abcdef0123456789abcdef",
        "asw": "0123456789abcdef0123456789abcdef",
        "type": "FooType",
        "name": "FooBar",
        "timeout": 3600
    },
    ...
}

Example Flow

example flow

Author

Mathias Schäffler

License

LGPL-2.1