Will SmartSense Temp/Humidity Sensor work from inside a fridge

Hi all!

I’ve done a lot of reading recently on setting up a fridge for dry aging meat at home and I’d like to put a humidity/temperature sensor inside the fridge so I can be alerted right away if something goes wrong.

Does anyone know if the sensor will be strong enough to transmit from inside the fridge? Also, I’m thinking of using IFTTT to start a log going. Anyone have any experience with that? Suggestions?

Thanks!

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Short answer: it may work inside the fridge in terms of recognizing events, but it may not be able to transmit to the hub. (edited to add Several people report this is working for them, so it’s worth trying. It may just depend on your particular refrigerator model, in particular the gasket design.*)

If the regular sensor can’t get a signal through, there are other things you can try. Different people use different approaches for this. The best in terms of energy use and fridge integrity is what commercial kitchens do–get a device with a wired probe. The probe goes inside the refrigerator, the door closes on the cable (which is thin), and the transmitter goes outside the fridge.

These are easy to find, although I don’t know if anyone’s integrated one with smartthings yet. You might be able to use one of the flood detectors or plant sensors which also work with a probe and measure temperature, just check the specs to see their operational temperature ranges and look for one with the thinnest probe.

Hi @maniac1181, I’m doing something similar with Philio Tech’s older PSM01 zwave sensors and Grovestreams GroveStreams SmartThings QuickStart for logging a couple refrigerators (temp, open/close).

While these devices don’t monitor humidity, they are inside the frig and still report temp readings just fine whenever it changes. I would imagine the SmartSense device would work depending upon the distance from the hub, and/or if you have any other AC powered zigbee devices around to act as repeaters.

I couldn’t find specs for the SmartSense device and what temp range they’re suppose to work in, so double check that.

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What model refrigerators? I’m astonished, honestly, if a zwave or zigbee device can transmit from inside unless there’s a plastic part somewhere.

There were some refrigerators made with in-door icemakers that had plastic shielding instead of metal in some sections, but there was definitely heat loss in that area and most manufacturers changed back to all metal.

Classic spy stuff–put your mobile phone in the refrigerator and no one can find your geolocation. :wink:

http://thelede.blogs.nytimes.com/2013/06/25/why-snowdens-visitors-put-their-phones-in-the-fridge/?_r=0

Hi @JDRoberts. One frig is a new Kitchen Aid side-by-side stainless with freezer on the bottom. The sensor is at the bottom of the door, close to the edge so the magnet on the other door would trip the contact sensor. The frig is about 30 feet from the hub through a couple walls.

The other is a GE Profile side-by-side frig/freezer. The sensor on that is 1/2 way down and mounted on the center vertical divider separating the frig/freezer about 3 or 4 inches in from the edge so that a magnet mounted on one of the door trays can trip it and closing the door doesn’t hit it when closing. The frig is in the garage about 30 feet away from the hub, through a steel garage door, and a couple walls.

I was concerned about transmitting, but these devices have been excellent. Considering the amount of plastic, steel, and magnetic rubber seals, these devices have never failed.

I have a freezer that I plan on using one of these in:

http://www.philio-tech.com/products/PAT02-B.pdf

Here are their other sensors:

http://www.philio-tech.com/products_sensors.htm

FYI the SmartSense multisensors, and the Open/close+temp, and Temp+Humidity sensors have all been able to regularly update my hub from inside the fridge and freezer though several house walls for many months now. Typical wood frame and drywall construction. For my usual multisensor in the freezer, the battery is holding up amazingly well, reading from “new/88%” to 77% in the last 5 months. The hub is straight line about 35 feet away.

Typical fridge, foam, metal sheathing, top freezer.

I wouldn’t run a wire though either the door seal or the case - too much heat leakage and risk.
EDIT - deleted old link sorry - here is a clip, the fridge still works:

Hey, if it works for you, great! No harm in trying if the sensor can handle the conditions.

I’d be looking for heat leaks, though. But that’s just me.

I’ve had a Multi in our fridge for over a year. I wasn’t sure it would connect, but it works fine. I have it set to ping me when the door is left ajar for more than 2mins, and when the temperature gets too high. Because it is a side-by-side, it is tall and narrow, and the temp reading varies more than 5 degrees from top to bottom. So where the multi is in relation to your meat could significantly affect the accuracy of your readings.

(I haven’t tried it in the freezer due to the extreme cold. I figured the battery would die out too quickly.)

Snowden’s fridge-as-faraday doesn’t actually work, by the way. We put a phone in a fridge and called it. There are YouTube videos. But it was probably the best insulator Snowden had at the time, and even if the mic were remotely activated, the audio would still be muffled. Apparently, better tradecraft would have involved a cocktail shaker, but I’ve read Snowden doesn’t drink.

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Pinging when the door is left open is a completely different use case since, well, the door is open. :wink:

Are you getting regular temperature reporting while the door is closed?

While not a z-wave device connected to ST, I am using a $8 tower sensor connected to my Acurite (My Backyard) weather station. Given these are designed for the outdoors the cold freezer temp has no effect. It has been in the freezer since the first of March and during this period I have received 2 reports that connection was lost. In each case, this connection was restored within minutes. Overall, the signal strength between the tower and receiver is pretty strong.

Wow guys!

Thanks a lot for all the responses! I’ve ordered the sensor and will start doing some reception tests as soon as I get it. If all works well, I should have some aged ribeye by mid June!

I’ll re-update this with my findings!

@johnconstantelo, thanks for the grovesteams info! Seems much easier than getting things to work with IFTTT.

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Talked to a friend who teaches college engineering and has done a lot of tests on this, since it’s a great classroom demo for weakest link design. He says the gasket design of the refrigerator makes a big difference. Put aluminum foil ropes around the gasket, and the phone usually stops ringing. :wink: You still have a good heat seal from the rubber, but it’s not signal proof.

That’s cool – Science!

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I have had a SmartThings Multi in my freezer in the garage for almost a year. I use it to report temperature and if someone leaves the door open too long. It has worked pretty well! It actually saved me once when the thermostat stuck closed after I had defrosted the freezer and the compressor was running non-stop. The Multi reported temperatures well below zero and I was able to quickly diagnose the problem before it became a major malfunction. I have found that I needed to make an adjustment to the reported temperature, probably because I have the sensor near the top of the freezer, just inside the door gasket. Occasionally I note a delay in reporting, but other than that it has been one of my favorite and most beneficial placements. It is located about 40 feet from the hub, through several walls and rooms.

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ST Multi working for open/close, movement, temp in a SubZ fridge.

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I have a ST Multi in my deep freezer. It has been working flawlessly for the past month or so. It has no problem transmitting the temperature (generally between -7F and 15F…frost free) when the door is closed.

Never again will the wife or kid ruin another freezer full of meat!

I generally find it safer to always blame the kid, even if you know it was the wife. I’m just sayin’…

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You will be stuck with broccoli thru out the week… :wink: and plus cold beer is a must with summer approaching… What next hue inside the fridge?

It’s funny you say that because I did blame the kid first. I was not pleased. Cow blood from frozen livers everywhere. It didn’t need to be upright because it was frozen! The wife admitted it was her, so I had to apologize to the kid.

If the fridge light changed color from green to red as the alcohol supply dwindled…

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