freezer thermometer with remote access

[Allan]

Am looking for a freezer thermometer that can be read (& receive alerts?) remotely.

My sister has a freezer in a weekend cottage with a load of food in it, and it would be a shame to loose it. There are occasional outages (which are bearable) and sometimes just one circuit on the RCD trips (which we may or may not know about)

We have hive for heating (but they don't appear to have any thermometers of any sort), and a couple of webcams, so we know if the power goes off in the whole house or on certain circuits, but it would be nice to get some warning if the freezer gets too warm (there is a friendly neighbour who will go in and flick a breaker switch as necessary)

Any recommendations/thoughts?

TIA

[Martin Brown]

You have internet connection. My suggestion would be to put a smart lamp on the same circuit as the freezer and check that it is controllable once a day with a script. You might get the odd false positive where the lamp has just gone AWOL for reasons of its own.

Most freezers can stand 48 hours without power provided you don't open the freezer door. Alternatively you could use a webcam with audio to listen for the freezers own audible alarm (assuming it has one).

[Brian Gaff]

Many burglar alarms can ring a certain number silently I believe, so maybe the interruption of the voltage is the best thing to detect and then be informed by phone. Brian

[Tim Watts]

ZWave has temperature sensors with probes on wires and the ZWave signal can generally manage from a house to a shed, if your walls aren't foil lined or mentally thick.

Needs 12V. Try Qubino too - they might have a mains one, you'll need to pop in a plastic box and run the probe out.

The harder part is to choose a sensible Hub - but it can be done with a Pi and

The benefit is that you can pop on a flood sensor or two, room temperature sensor to alert to freezing conditions and turn a couple of lights on and off for anti burglar reasons.

[Theo]

There are thermometers with wireless sensors, like this:

of similar things across ebay and amazon)

and some are network accessible:

I'd probably want one where the sensors speaks wirelessly to some kind of external box. The sensor itself is thus very low power (small battery) and doesn't emit any heat to disturb the freezer, while the external box might take a few watts.

I'd guess the first kind speak basic 433MHz or something similar, and wouldn't be surprised if someone has reverse engineered the protocol.

Theo