Finally… Beware that you might need to upgrade Node-RED. The “App” field should be a dropdown, and it needs to show a pencil icon to the right. Older versions might show just a text field, but it does not suffice to just enter some text in the “App” field.
The above screenshots are no longer valid for later releases of the TTN’s Node-RED library. Read on!
Thanks Arjan, I now have meta data in node-red. Next step is making a function that combines the specific metadata and pay load fields to a twitter message.
Thanks for the other info too. I will have a look into ttnmapper.org and will register my SODAQ device and fill in some blank spots.
Solution:
“ttn message” (node block)
“function” block with return “msg.metadata”
“debug” block with for instance “msg.frequency”
This show the ‘frequency’ meta data in the debug window
1/30/2017, 10:33:55 PMnode: df2f9ca1.3092d
msg.frequency : number
868.1
useful tip. thank you
Note that you’d get multiple gateways in your meta data if the node’s packets were received by multiple.
You can also use the function block to return the data just as you want it. Like:
// Just a helper variable to use below
var gateways = msg.metadata.gateways;
return {
// Assuming the TTN Payload Functions decode some bytes from the node
// into a "location" in the output:
mylocation: msg.payload_fields.location,
// Some fields from the metadata
freq: msg.metadata.frequency,
cr: msg.metadata.cr,
dr: msg.metadata.dr,
// Combine RSSI and SNR of all gateways into two arrays:
rssi: gateways.map(gw => gw.rssi),
snr: gateways.map(gw => gw.snr),
// ...or: get an array with an object for each gateway:
gateways: gateways.map(gw => {
return {
location: {
lat: gw.latitude,
lng: gw.longitude
},
rssi: gw.rssi,
snr: gw.snr
}
})
};
When printing “complete msg object” in a debug node, you’d then get something like:
{
"mylocation": {
"lat": -33.8688,
"lng": 151.2092
},
"freq": 868.1,
"rssi": [-36, -45],
"snr": [9, 9],
"gateways": [
{
"id": "eui-b827ebffff5fe05c",
"location": {
"lat": 52.12345,
"lng": 4.12345
},
"rssi": -36,
"snr": 9
},
{
"id": "eui-5ccf7ff42f1970ec",
"location": {
"lat": 52.54321,
"lng": 4.54321
},
"rssi": -45,
"snr": 9
}
]
}
Or to get a msg.payload for a Node-RED Twitter input:
var gateways = msg.metadata.gateways;
msg.payload = "Received by "
+ gateways.length
+ " gateway(s), with RSSIs "
+ gateways.map(gw => gw.rssi).join(", ")
+ " and SNRs "
+ gateways.map(gw => gw.snr).join(", ")
;
return msg;
…to get
Received by 2 gateway(s), with RSSIs -38, -44 and SNRs 9, 9Works great, see below !
Thanks for making the story complete.
brandevoort IoT @brandevoort_eu 24s25 seconds ago
More
Received by 1 gateway(s), with RSSIs -49 and SNRs 7.8
Nice. If you want to get rid of the plural thing when not needed, then:
// Just some helpers
var gateways = msg.metadata.gateways;
var count = gateways.length;
var s = count === 1 ? "" : "s";
var rssi = gateways.map(gw => gw.rssi).join(", ");
var snr = gateways.map(gw => gw.snr).join(", ");
msg.payload =
"Received by " + count + " gateway" + s +
", with RSSI" + s + " " + rssi +
" and SNR" + s + " " + snr;
msg.payload =
`Received by ${count} gateway${s}, with RSSI${s} ${rssi} and SNR${s} ${snr}`;This is gold-plating but good for learning 
I end up with the following twitter message :
brandevoort IoT @brandevoort_eu 34s34 seconds ago
Object position : 51.4571686 , 5.6171753
Gateway ID : eui-b827ebfffe517647
RSSI=-48 SNR=9.8
I still have to catch a second gateway to see what it looks like in “plural” mode
Hi @arjanvanb and @mvbakel,
I have been reading through this post and the node-red quick start as well.
I finally made the flow as shown below.
But when I inject the time stamp, it shows
22/08/2017, 19:40:32node: function
msg : Object
object
_msgid: "8cd2f01e.744d4"
topic: ""
payload: 1494689048489
Can you please let me know what I am doing wrong.
Regards,
Sid
My flow is :
[{“id”:“f2a8dc4b.63b01”,“type”:“ttn message”,“z”:“ba1baf4e.520de”,“name”:"",“app”:“9a11302e.19f89”,“dev_id”:“sidsfirstdevice”,“field”:"",“x”:256,“y”:212,“wires”:[[“9f122e7e.f7cfc”]]},{“id”:“a86ec9a1.145318”,“type”:“debug”,“z”:“ba1baf4e.520de”,“name”:“device”,“active”:true,“console”:“false”,“complete”:“true”,“x”:511,“y”:124,“wires”:[]},{“id”:“d53d0a4b.c61a18”,“type”:“ttn send”,“z”:“ba1baf4e.520de”,“name”:"",“app”:“9a11302e.19f89”,“dev_id”:“sidsfirstdevice”,“port”:“1”,“x”:550,“y”:386,“wires”:[]},{“id”:“b62e1981.26e528”,“type”:“ttn device”,“z”:“ba1baf4e.520de”,“name”:"",“app”:“9a11302e.19f89”,“dev_id”:“sidsfirstdevice”,“event”:“activations”,“x”:249,“y”:124,“wires”:[[“a86ec9a1.145318”]]},{“id”:“9f122e7e.f7cfc”,“type”:“debug”,“z”:“ba1baf4e.520de”,“name”:“message”,“active”:true,“console”:“false”,“complete”:“true”,“x”:507,“y”:218,“wires”:[]},{“id”:“f3454569.753e38”,“type”:“debug”,“z”:“ba1baf4e.520de”,“name”:“function”,“active”:true,“console”:“false”,“complete”:“true”,“x”:551,“y”:303,“wires”:[]},{“id”:“4549c7c1.fa3508”,“type”:“inject”,“z”:“ba1baf4e.520de”,“name”:"",“topic”:"",“payload”:"",“payloadType”:“date”,“repeat”:"",“crontab”:"",“once”:false,“x”:188,“y”:324,“wires”:[[“d53d0a4b.c61a18”,“f3454569.753e38”]]},{“id”:“9a11302e.19f89”,“type”:“ttn app”,“z”:“ba1baf4e.520de”,“appId”:“sidsfirstapplication”,“region”:“se”,“accessKey”:“ttn-account-v2.R7yqoOfazcI7IWHgMCVmeOM8tXI9mC7QwcE6H2VYCtg”}]
I am loging the messages from my ttn node running the cayenneLPP sketch to a local file on my desktop computer using NodeRed. This works using the following NodeRed flow:
I would like to have the timestamp out of the metadate which i obtained with the following code in the function node:
return {
//Some fields from the metadata
time: msg.metadata.time };
to be logged with the payload. How can I convert the time metadata to be a payload type and combine it so that I get one line log entries with timestamp first followed by the payload. Everything I tried was not successful…
Can somebody give me a hint?
Yes, thanks, but SPLIT only works on the payload part of the message and my extracted time from metadata is not payload… I do not see how split and join would help eafter looking at the example but I am a nodered newbie
deleted…
@BoRRoZ Thanks… I have followed the guide, i deleted the previous node-re nodes and added the new event and uplink ones and I do have added discovery info… but nevertheless no luck and no error message in the console.
Its only the OTAA part which does not work…
Because it was running with 2.0.2 I did only install the new ttn nodes and did not reinstall node-red or node.js. Maybe i would have to reinstall everything?
problem solved after reinstall…
Just to say I checked my node-red TTN nodes and they are both connecting and working OK with an LMIC OTAA node (Heltec).
Did you leave the region field empty? - just check that you really did type “eu” in there (and it is not “greyed”)
Try this code in your function ?
var msg2= msg
msg2.payload.time = msg.metadata.time;
return msg2;
@CurlyWurly Did you leave the region field empty?
hmm… there is no region field. Probably in the old version but in the 2.0.4 version there is this discovery thing…with the old version everything was working ok.
and i will try your code as soon as I get connected again of course. Thanks…
I tried the code in one of the connecting nodes and it is not giving the time but the payload
