I have a network of ESP32 based devices which monitor the moisture levels in my Houseplants. Each device identifies itself to NodeRed via an MQTT message with the IP Address of the device as the Topic. I want to be able to know if any device has stopped working and am therefore storing the last time…

It certainly doesn't give a very pretty result. A work-around might be flow.set(ip.replace(/\./g, '_'),currentTime);

The reason that is happening is because we are allowed to specify a javascript object description as the id. For example, one could write flow.set("a.b", 42) and the a.b would be treated as meaning property b of object a. So by using "192.120.1.23" you are creating a multi-dimensional array named …

This seems to work flow.set(`"${ip}"`,currentTime) By the way, you don't generally need semi-colons on the line ends in javascript any more.

Thanks for the suggestions. My own workaround was to just use the last segment of the ip address and concatenate that to "IP". All my addresses are on the local network so I think that will work as well. I'm 76 years old and started off life 52 years ago as a COBOL programmer where the semi-colon …

Incidentally you can achieve an alert when one of your ESPs goes offline by using a single trigger node, no code at all. :laughing: Each ESP is using a unique msg.topic , it's IP address. Send all the messages to a trigger node set to send nothing, wait for a certain time and then send the last me…

Um, Why not use the LWT of MQTT? LWT is sent if a device goes offline. So you have a MQTT-IN node and it listens to the LWT topic. Then if one of the devices goes offline, you get a message and it (the message) will tell you which device it is - bonus. :wink: I know this is an older version of…

Thank you for that suggestion I will give it a try. Although often I like to use tried and tested methods that are independent of the platform I'm using. Because my moisture sensors are battery powered I'm putting them into deep sleep between samples and the sample interval is 30 minutes. When the d…

I'm not sure whether this is relevant as I am not using the NodeRed MQTT broker but thank you for your suggestion and please correct me if I'm wrong. You might also like to read my response to @jbudd 's suggestion above

Yeah, he and I replied at about the same time. His way is also nice and does work with given nodes. You set the LWT on the device. Not the broker. I showed you my config to save me typing.

It seems that lots of folks use Node-red primarily as an environment for writing and running snippets of javascript and indeed it is very approachable for that (I have no idea how to write or run javascript outside of Node-red!) Don't neglect all the other nodes though, it is very a capable languag…

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Is this a bug - flow.set()

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system Closed 20 January 2025 09:12 13

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Is this a bug - flow.set()

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