rroemhild/ruuvitag-lorawan

Publish RuuviTag sensor data with LoRaWAN

Publish RuuviTag sensor data with LoRaWAN

This repository contains the up to date snippets for the Publish RuuviTag sensor data on The Things Network tutorial.

This PoC uses settings specifically for connecting to LoRaWAN networks within the European 868 MHz region. For other regions usage, please see the settings.py and lib/lorawan.py file for relevant sections that need to be changed.

Data Format

For each RuuviTag we send 8 bytes. The RuuviTag ID is the index from the mac address in the settings.py list. We match this later in the decoder.

Offset	Description
0	Tag ID (8bit)
1-2	Temperature in 0.005 degrees (16bit signed)
3-4	Humidity in 0.0025% (16bit unsigned)
5-6	Batter voltage + 1600 (16bit unsigned)
7-8	RSSI * -1 (8bit)

In example for 2 RuuviTags the following payload will be send:

b'\x00\x05$\x8e\xf8\x04\x8f[\x01\x11d/@\x05\rB'

ID	Temp	Humid	Voltage	RSSI	ID	Temp	Humid	Voltage	RSSI
00	0524	8EF8	048F	5B	01	1164	2F40	050D	42

Read more about the data format used in this project in the Ruuvi Sensor Data Format 5 Protocol Specification.

Payload Format Decoder

Example payload format decoder for the The Things Network Console. The var map is used to identify each Ruuvitag by name. The oder must match the order in the RUUVITAG list in the settings.py.

var map = ["outdoor", "livingroom"];

function Decoder(bytes, port) {
  var ruuvitags = {};
  var tags = bytes.length / 8;

  for (i=0;i<tags;i+=1) {
    var temperature = (bytes[1] << 8) | bytes[2];
    var humidity = (bytes[3] << 8) | bytes[4];
    var battery = (bytes[5] << 8) | bytes[6];
    var rssi = bytes[7];

    var name = map[bytes[0]];
    ruuvitags[name] = {
        "humidity": parseFloat((humidity * 0.0025).toFixed(2)),
        "temperature": parseFloat((temperature * 0.005).toFixed(2)),
        "battery": battery + 1600,
        "rssi": rssi * -1
    };

    bytes.splice(0, 8);
  }

  return ruuvitags;
}

// TTNv3
function decodeUplink(input) {
  return {
    data: Decoder(input.bytes, input.fPort),
    warnings: [],
    errors: []
  };
}