Temperature and humidity meter

[Orchidtinkerer]

Hello everyone,
I wanted to start a topic on temperature and humidity meters. I think it is an under-reported subject. I know when it comes to sensors you can get manual and digital ones. Then you can get high precision and budget ones.
I've seen some people say that budget ones are not worth it - maybe but I think this century sensors have become better than they used to be and cheaper. The high precision ones will always be very expensive.

I started as probably many did with a thermopro monitor like this one Amazon.com

but after owning it and comparing it to others I have decided it is the slowest to react to changes and the most inaccurate sensor I have.

I have tried these Amazon.com

they are very good value and accurate but they are rather small and don't have a max -min storage

the best one I have tried and wanted to share with you today is this one Amazon.com

It has max-min values, a very sharp display, seems accurate and responsive to changes, my favourite budget monitor I have tried so far.

I'm not affiliated with any of these, I just thought I'd share my findings since I know lots trust the number 1 best seller which to me is the most inaccurate one and it is hard to know out of the other 1000's of chinese brands which ones to trust.

I cannot comment on how they would last with water or very high humidity. I've heard people break theirs if they get them wet too much which I suppose can be an issue with any sensor and maybe a manual one would be better suited.

The manual ones can be more reliable than the digital ones and don't use any batteries so there is plenty of good choices but also plenty of bad ones out there.

I recently tried a weather station that had all unnneeded additional features, barometer, alarm, usb phone charger and an animated screen but the sensors were rubbish which to me is the most important, some people just want something nice to look at since it only had glowing reviews.

Hope this helps someone.

Happy growing.

[SouthPark]

I haven't used temperature and/or humidity sensors for my plants before. But I do like to tinker with sensors. I ordered some HCZ-H8-B humidity sensors just a moment ago, after reading your post ----- and planning to see how these perform ----- as in see how long they just keep working for.

For temperature measurements ----- the waterproof version of the ds18b20 might be ok. The ones housed in a cylindrical metal can thing.

[Ray]

Orchidtinkerer, your choice looks like a decent one, assuming they're reasonably accurate.

Last June I bought this one from Govee, also through Amazon, at another grower's recommendation, and it seems pretty solid, too.

For remote monitoring that I can monitor from my phone, I am a big fan of the Sensorpush line, although they are a lot more expensive.

[WaterWitchin]

Interesting. I have two of the very first one you showed OrchidTinkerer. Had for years. I think perhaps I'll get the third one you show, or Ray's latest and give one a whirl. I used to use them mainly for the humidity reading because I wasn't worried about temperature that much.

In my new grow space, low temps are a concern if my heater goes out. (Formerly were in basement, which never got cold enough to actually kill anything even if heater went on the fritz.) I like the idea on Ray's of being notified on my cell if it goes outside a preset range.

[Orchidtinkerer]

Ray yours looks amazing and so cheap.

From what I have gathered there seem to be two different kind of humidity sensors, the old fashioned type had a +-5% discrepancy and the new ones have a +-3% accuracy. They seem to be faster to pick up changes than 5% accurate ones too.

I will see if I can find a govee here. Good find

[Ray]

When I first got out of school, we did a lot of investigation around how ambient conditions can affect a molten ceramic at 2000C, so knowing the water content of the air was pertinent.

Back then, the humidity was best measured with a sling psychrometer (probably still is), but a certified gauge was a reasonable substitute, and the sensor consisted of human hair that would shrink or elongate with the RH.

Nowadays, there are capacitive (metal oxide between metal electrodes; the capacitance changes with RH), resistive (similar mechanical setup, using a salt in between metal electrodes; conductivity of the salt changes) and thermal, where the conductivity of two identical pieces of metal are compared, one being in dry nitrogen.

My guess is that all of the less-expensive ones we get are the salt conductivity type, as they are cheap and don’t require the constant recalibration of the capacitive ones.

[Orchidtinkerer]

right I got myself a govee too and I am happy with the responsiveness, screen is just average, ie in the wrong light it is hard to read but that is minor.

What I am abit annoyed about trying to set it up is that they want to know my location, my phone number and my email address before I can set up the home app. This was not mentioned anywhere and why do they need all my info?
Is this correct? The app I downloaded and all I could find was only downloaded 200 times so something doesn't seem right...

I was going to post a side by side comparrison after letting them set for an hour but I want to know if I have downloaded the right app now so here is a quick picture of what you can expect after 10 minutes. Note these will not be accurate measurements as the meters need to adjust first but it gives you a good idea, most are withn +-5% - now look at the thermopro (the white one on the right). More than 20% off on humidity and it takes over an hour to change by like 10%

[camille1585]

Originally Posted by Orchidtinkerer

What I am abit annoyed about trying to set it up is that they want to know my location, my phone number and my email address before I can set up the home app. This was not mentioned anywhere and why do they need all my info?
Is this correct? The app I downloaded and all I could find was only downloaded 200 times so something doesn't seem right...

Try getting to the app directly from the website. That way you are sure to have the brand's app, and not some knockoff. I'm paranoid and usually do that when I need the app for a product. I just tried it for govee, and they have one app for all their products called govee home, with 500k+ downloads...(Android version)

[Orchidtinkerer]

Final results after settling for one hour

[SADE2020]

Originally Posted by Orchidtinkerer

right I got myself a govee too and I am happy with the responsiveness, screen is just average, ie in the wrong light it is hard to read but that is minor.

What I am abit annoyed about trying to set it up is that they want to know my location, my phone number and my email address before I can set up the home app. This was not mentioned anywhere and why do they need all my info?
Is this correct? The app I downloaded and all I could find was only downloaded 200 times so something doesn't seem right...

I was going to post a side by side comparrison after letting them set for an hour but I want to know if I have downloaded the right app now so here is a quick picture of what you can expect after 10 minutes. Note these will not be accurate measurements as the meters need to adjust first but it gives you a good idea, most are withn +-5% - now look at the thermopro (the white one on the right). More than 20% off on humidity and it takes over an hour to change by like 10%

I have a few models myself, 4 units are the same as yours; the one in the left. My discrepancy is about 5% un humidity in between one brand and the other, the Temp seams fine, but I have adjust my growing in winter to the base of those meters..meaning that is my point of reference. You have 3 out of 4 with similar data, that is a POR (point of reference)
Great chat though i think we all struggle with Temp/Hum/Light measurements.

Thanks for sharing!