What's the interface to use between a cellular Arduino and openHAB?

I’ve built a device to monitor my cabin that doesn’t have internet, using a cellular shield and a Hologram SIM. I guess this question is really open to ANY remote Arduino or other IoT device.

  • The device is monitoring temperature (freezing water) and power (loss of monitoring and no heat lamp running in water cubby)
  • I would prefer to not open any ports at home and host a service like MQTT here.
  • Hologram does have Hologram Cloud and Data Routing but there doesn’t appear to be any services that openHAB can connect to.

I suspect that the answer is probably self-hosted MQTT or some sort of cloud service that has MQTT.

Is there something to accomplish this?

So, no personal data… humm…
Why not use one of those public mqtt servers??
Loads of people use them, they are, well, public, so you don’t need to open any ports, and if you’re only dumping temperature and power data, I wouldn’t be too overly fussy about that kind of data.

It would be just like having a secondary mqtt broker, that you hook up to openHAB, and listen in a specific topic.

Seems to be a simple and pretty decent fix.

I have a feeling that’s the way I’m going to end up going.
Looking at MyQtthub.com and sub/pub to that.

The only additional note is throw in there is, the power data could be hypothetically be used to find out whether or not someone is at home to plan a physical attack.
Not sure if this is something that you’d be at risk of… but yeah. Something else to consider.

ahh… even that, nobody knows what this is powering

Humm… point. But, knowing that no power is being used, one could assume that no one is at home. That was what I was referring to. But it’s up to you to decide whether or not it is relevant :slight_smile:

Edit: this might be overkill, but there’s this also:

CloudMQTT offers a $5 a month plan that would support an encrypted connection. You could also get a low powered VPS to host your own MQTT broker, though be careful to lock it down.

Hologram appears to support a REST API so the HTTP binding might be used to access the data through Hologram Cloud.

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WAY overkill, especially since I don’t have internet up there. That means that I would have to convert this to an RPi project and would also have more cell traffic $$$$.

Edit: Also, the power is just whether the Arduino (cabin/heat lamp) is still receiving power, it’s not looking at usage or anything like that.

MyQttHub is free, as best I can tell private, and it even allows for encrypted traffic. However, even though the MQTT functions built into the modified Adafruit cellular library allow for me to set the port, I haven’t figured out how to add a cert and would probably have to build my own, not to mention it will increase the traffic. $$$$

Either way, it seems like MQTT is the way to go. Thanks for the input, I knew you’d have some Rich.

You may be able to setup the “Data Router” in Hologram to send a webhooked message to the openHAB cloud connector and your instance of openHAB at home.

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