Permanent temperature probe remote sensor

Ah, getting more for your money. Also a good idea!

Thanks for confirming that this could work. Almost certainly the cheap and easy option.

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IMHO I would wire these locations with Type K thermocouples for long term reliability. The only way I am aware of to do is to use an Arduino with Hubitat Hubduino software/driver.

I realize it will be more work to get started, but will have superior reliability. You could even run dual thermocouples to each location and use one as a backup in case the device was damaged by some external occurrence (falling limb , hail, etc)

In addition, a thermocouple does not have any temperature limits in such a location. They will easily withstand the hottest hot and the coolest cold.

Just a note, the above discussions focus on battery life, not device failure. Folks have posted both good and bad results putting a Z-Wave or Zigbee device outdoors. Although I'm not sure what type of environment a roof void is.

I feel like i post pretty similar replies to most queries. But.... nodemcu with a ds18b20 (or a dht22) temp probe. I use loads of them.

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I used zooz 4 in 1 sensors for my attic and basement with hard-wired for power. Been working for a few years with no issue. I just wanted to monitor the temp but throw on humidity and lux as a bonus.

a DS18b20 probe with a Qubino module.
This QUBINO Flush ZMNHBD3 Z-Wave 2 relays - the smallest double relay switch - - Amazon.com or similar.

The Qubino module will operate from a 24V power supply.

If you can crimp connectors yourself, a probe with 1.5m cable costs almost noting.

This confirms what I suspect! I like the idea of just a Type K thermocouple (or a few of them) in the inaccessible area. Almost nothing to go wrong there. The things that might need attention - the electronics and power source - can be located in an accessible place.
The question is, what's the best strategy in terms of effort/expertise required!
The next response, re nodemcu, I like... but it would be a learning curve!

Researching this a bit, it sounds ideal. Cheap to roll out, I could install loads of them. But whilst I'm very practical, good with soldering, fairly technical... I have not dipped my toe in the programming modules water.
Honestly, how much of a learning curve is it? I appreciate that once mastered, I could do all sorts of things, but I don't really want to get into heavy programming. I would rather pay a little bit more to buy a module that is ready to connect to Hubitat, and have a probe wired to it. Is there an half way house like that?

Yes, I could crimp or solder no problem. They look pretty good - the relay switches also have thermocouple inputs, yes? So it just sends data back to Hubitat? Sounds good, but they are moderately pricey. I'm in UK, and they're £25 a piece. Given that I would like to roll out maybe half a dozen, it adds up.

@Bagpuss

I can't program whatsoever. Check out the konnected software. Doddle. Feel free to shoot me a pm if you like, but it's easy.

If you prefer, I'm UK based too and not adverse to a call.

The fact that I wanted so many meant that scalability and low cost was important. And ease of replacement in event of equipment fault.

All this is off the shelf components. And cheap ad chips.

I've asked about your desire to crimp connectors because of this:

or similar.

When you plug them in a Qubino module, Hubitat will report the temperature.

Since you are unlikely to be using the relays, it is kinda wasteful but all things considered,
this is the best combo I could find.

For extra 1-2 of your money :), you could have probes with 2m (or longer) cables; bury the probe but have the module easily accessible.

The node MCU route is more technical but you would not be blazing new territory.

I suggest you investigate the combination of:

  • Hubduino Firmware
  • NodeMCU
  • T/C to SPI board Be sure you get a board with the components circled. They are for filtering and protection of the MAX31855. Without them the MAX31855 is more at risk from various induced voltage spikes.

I don't know if Hubduino supports the MAX31855 so you should contact @ogiewon (the Hubduino author) to see if Hubduino will "read" the MAX31855. If so all the software is available and all you have to do is wire the thermocouples, Max31855 board and NodeMCU.

PS I've used the MAX31855 with a regular Arduino and have had good luck.

If you have any questions regarding the Thermocouple wiring please let me know.

Good luck,

John

Thank you for all the input. I think I've made myself some homework! Whilst more work, I know deep down that learning to do it with the basic components is the right way to go.

I'll do some research and shopping, and come back as and when I get stuck.

Thank you, that's most kind. I'll get some supplies in, have a play, and maybe a chat on the blower would help me make some leaps of progress.

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Just an added thought.... you cannot solder thermocouples.

For connections you can use small crimps or special connector mates from ebay. Type K connectors

Yes, HubDuino already has support for the MAX31855 thermocouple board.

Great!
Can he do multiple 31855's on one NodeMCU?

What did you end up doing? I have a very similar set of requirements for a temperature sensor in the attic.

Ah, yes, you’ve got me.
I followed all the good and helpful advice above, bought all the components, and then… life got in the way.
Also, as a relatively quick solution that met some of my needs, I bought a SwitchBot temperature sensor and hub.
This has the benefit of working out of the box, and storing records, graphing them nicely. Ticks lot of boxes, if I’m honest.

It’s a shame it doesn’t integrate with Hubitat, but maybe one day somebody will write some nice code for it.

It’s running on batteries at present, and when they die, I’ll probably do a trip into the loft space and hard wire it in.

I’d still like to get the above project working, for other applications. When I get a moment, I’ll work on that. Just need to build the extension first. :wink: