Node-RED function to decode Axioma water meter payloads.

decodeAxioma.js

/* jshint esversion:6, bitwise:false, node:true, strict:true */
/* globals msg */
"use strict";
/**
 * Node-RED function to decode Axioma water meter payloads.
 * Example assuming that msg.req.body contains an HTTP POST callback from The Things Networks.
 */

function statusAxiomaShort(s) {
	const messages = [];
	switch(s) {
		case 0x00: messages.push('OK'); break;
		case 0x04: messages.push('Low battery'); break;
		case 0x08: messages.push('Permanent error'); break;
		case 0x10: messages.push('Dry'); break;
		case 0x70: messages.push('Backflow'); break;
		case 0xD0: messages.push('Manipulation'); break;
		case 0xB0: messages.push('Burst'); break;
		case 0x30: messages.push('Leakage'); break;
		case 0x90: messages.push('Low temperature'); break;
	}
	return messages;
}

function decodeAxiomaShort(raw64) {
	const b = Buffer.from(raw64, 'base64');
	let epoch, state, volume, pastPeriod;
	let pastVolumes = [];
	let i = 0;
	let error;

	try {
		epoch = b.readUInt32LE(i); i += 4;
		state = b.readUInt8(i); i += 1;
		volume = b.readUInt32LE(i); i += 4;
		while (i + 8 <= b.length) {
			pastVolumes.push(b.readUInt32LE(i)); i += 4;
		}
		pastPeriod = b.readUInt32LE(i); i += 4;
	} catch (ex) {
		error = true;
	}

	return {
		date: state == 0 ? (new Date(epoch * 1000)).toISOString() : undefined,
		state: state,
		stateMessages: statusAxiomaShort(state),
		volume: state == 0 && volume ? volume / 1000.0 : undefined,
		pastVolumes: state == 0 && pastVolumes.length > 0 ? pastVolumes.map(v => v / 1000.0) : undefined,
		pastPeriod: state == 0 && pastPeriod ? pastPeriod : undefined,
		error: error ? error : undefined,
	};
}

function statusAxiomaExtended(s) {
	const messages = [];
	if (s === 0x00) {
		messages.push('OK');	//No error; Normal work; normal
	} else {
		if (s & 0x04) messages.push('Low battery');	//Power low
		if (s & 0x08) messages.push('Permanent error');	//Hardware error; tamper; manipulation
		if (s & 0x10) messages.push('Temporary error');	//Dry; Empty spool; negative flow; leakage; burst; freeze
		if (s === 0x10) messages.push('Dry');	//Empty spool;
		if ((s & 0x60) === 0x60) messages.push('Backflow');	//Negative flow
		if ((s & 0xA0) === 0xA0) messages.push('Burst');
		if ((s & 0x20) && !(s & 0x40) && !(s & 0x80)) messages.push('Leakage');	//Leak
		if ((s & 0x80) && !(s & 0x20)) messages.push('Low temperature');	//Freeze
	}
	return messages;
}

function decodeAxiomaExtended(raw64) {
	const b = Buffer.from(raw64, 'base64');
	let epoch, state, volume, logEpoch, logVolume;
	let deltaVolumes = [];
	let i = 0;
	let error;

	try {
		epoch = b.readUInt32LE(i); i += 4;
		state = b.readUInt8(i); i += 1;
		volume = b.readUInt32LE(i); i += 4;
		logEpoch = b.readUInt32LE(i); i += 4;
		logVolume = b.readUInt32LE(i); i += 4;
		while (i + 2 <= b.length) {
			deltaVolumes.push(b.readUInt16LE(i)); i += 2;
		}
	} catch (ex) {
		error = true;
	}

	return {
		date: state == 0 ? (new Date(epoch * 1000)).toISOString() : undefined,
		state: state,
		stateMessages: statusAxiomaExtended(state),
		volume: state == 0 && volume ? volume / 1000.0 : undefined,
		logDate: state == 0 && logEpoch ? (new Date(logEpoch * 1000)).toISOString() : undefined,
		logVolume: state == 0 && logVolume ? logVolume / 1000.0 : undefined,
		deltaVolumes: state == 0 && deltaVolumes.length > 0 ? deltaVolumes.map(v => v / 1000.0) : undefined,
		error: error ? error : undefined,
	};
}

function autoDecode(raw64, body) {
	if (body.port == 101) {
		//Configuration frame
		return {};
	}
	//TODO: Adjust here if there is a good way to discriminate "Short" or "Extended" payloads,
	//for instance if all your sensors are of one type, or have different naming conventions.
	let rawLength;
	try {
		rawLength = Buffer.from(raw64, 'base64').length;
	} catch (ex) {
		rawLength = 0;
	}
	if (rawLength > 42) {
		return decodeAxiomaExtended(raw64);
	} else if (rawLength <= 9) {
		return decodeAxiomaShort(raw64);
	} else {
		//Might be a short or extended payload, so perform more sniffing on some fields to guess
		let snifAxiomaExtended;
		try {
			snifAxiomaExtended = decodeAxiomaExtended(raw64);

			//Test valid date difference in extended payload
			const maxValidDateDifferenceMs = 1000 * 86400 * 15;
			const date1 = new Date(snifAxiomaExtended.date);
			const date2 = new Date(snifAxiomaExtended.logDate);
			if (Math.abs(date1.getTime() - date2.getTime()) > maxValidDateDifferenceMs) {
				return decodeAxiomaShort(raw64);
			}
		} catch (ex) {
			return decodeAxiomaShort(raw64);
		}
		//Fallback to extended payload
		return snifAxiomaExtended;
	}
}

const result = {};

try {
	if (msg.req && msg.req.body) {
		result.decoded = autoDecode(msg.req.body.payload_raw, msg.req.body);
	} else {
		result.decoded = autoDecode(msg.payload, {});
	}
} catch (ex) {
	result.error = ex.message;
}

if (typeof msg.payload !== 'object') {
	msg.payload = {
		input: msg.payload,
	};
}

Object.assign(msg.payload, result);
return msg;

Grate job, thanks for sharing!

Looks awesome but... how did you capture the packet in the first place?
What HW are you using?

@PovilasID This is the payload sent over LoRaWAN (in my case, tested with The Things Network)

@PovilasID This is the payload sent over LoRaWAN (in my case, tested with The Things Network)

I am trying to capture Lora packet in transit using Software defined radio or aka usb stick with an antena. Manufacturer said that they do not encrypt the packets, so I should be able to just read them and use your scrip to decode them.
So in The Things Network you are not using your own gateway? Just using existing gateways to capture and then get access to the packets via API over the Internet?

Own gateway yes, but the important part is to control the application, as LoRa packets are natively encrypted

See https://nordiciot.dk/byg-dit-eget-intelligente-vandmalersystem-guide/ (in Danish, but figures and an automated translation should be sufficient)

@Mono-Co This decoder is never providing an output with something like {"Time":..., "Water"} as you got, so it is probably something else that was used. Compare with https://gist.github.com/Alkarex/4b5d1fef2ff84d483e2793ed009ef607#file-decodeaxioma-js-L92-L101

@Alkarex

Apologies, I'm using this decoder.. any suggestions ? https://pastebin.com/raw/35Mif5nk

No, it is unrelated to the work here