Hi everyone,
I am teacher in agriculture and I want to form students to the use of TTN to connect sensors in the fields. For that, I have a Raspberry pi and I installed on it influxdb, grafana and NodeRED.
I want the students to create an app on TTN, then send their API keys in order to parameter a node “MQTT IN” in Node Red, then store the info in influx.
I was just wondering if ther is a limit of MQTT IN node ? Is it a problem if I have 50 MQTT IN nodes, each one configured for each of the 50 app in TTN ?
This is more a question on if Node-Red can have 50 MQTT end points configured, if I understand your question it correctly.
I have never attempted that many, can’t see that Node-Red will have such a limitation. You limiting factor will be more likely the PI processing power.
Once the scripts have been compiled/assembled/interpreted, a Pi should be able to cope with devices operating at FUP - 50 devices, uplinks every 3 minutes (FUP minima), that’s one every 3.6 seconds, easy.
However the interesting bit will be the students hacking around the Node-RED web interface whilst setting up their flow.
Is there a reason why you are creating 50 separate apps on TTN? You may find things much simpler and easy to maintain if you have a single TTN app with 50 devices. That way you only need one API key, and your NodeRED becomes much easier to understand.
yeah, maybe …but why - what is the benefit? I can’t imagine why I would do it that way in “real” life because it creates a big maintenance overhead. I believe you’d gain more as a student by being a collaborator in the same app, especially given you want to feed the data into the same influx/grafana dashboard.
I don’t think the OP wants to do that - in a workshop they would create their own app and then do their own Node-RED setup / integration - all working independently from each other - just taxing the poor Pi whilst they do their setup.