High quality hygrometers


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Have posted this in  a couple other places....looking for as much feedback as I can get. 

 

Hey guys! I have been using cheapo hygrometers for years, but recently am getting annoyed that they keep breaking and that even after so called "calibrating" they tend to drift so quickly. I have been looking a some more updated hygrometer technology and wonder if any of you all have any experience with these, or similar hygrometers. I'm open to recommendations.

Ive been looking at these NIST certified ones that come precalibrated and seem nice. 

http://***.theweatherstore.com/nicewihyth.html

NIST Certified Wireless Hygrometer Thermometer 4380

Another option that I saw was this, I dont know if they are precalibrated, but I don't really see any option for calibrating.....this would simplify seeing the humidity in all my humidors and in different places in the humidors without having to open them. 

https://***.amazon.com/gp/product/B0...2&tag=tcbse-20

SensorPush Wireless Thermometer / Hygrometer for iPhone / Android - Humidity & Temperature Smart Sensor with Alerts

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I don't know, if after reading the information on one of these sites, that you are really getting certified instruments here. You are getting NIST traceability for their instruments!

The fact is that a NICT certification calibration is typically one or more points. NIST certs (calibrations) are often $100 or more per instrument. They indicate the certification traceability of the instrument used and then the actual points tested on 'your' instrument and the error. I have several around here and I went looking for one to post but I got most of mine before I started scanning everything for record keeping. If I cannot lay my hands on it in 5 minutes, I am afraid it is out of reach.

I think what you may be asking is "Where can I get NIST CERTIFIED CALIBRATED instruments?" Frankly, that is not what you are seeing advertised here.

You can get any instrument calibrated by a certified instrument calibrator. I have done this, but typically get the sensor maker to provide the NIST calibration for me. That way if the sensor fails they pull a new one out and certify that one.

There are of corse other aspects to be considered and that is the calibration of the instrument reading the sensor as well as the sensor itself.

I now run a measurable calibration signal through my controllers first to see what they are reading and what the display errors are. They are typically within about 0.2% and I trim that out at the 60rH mark and the 70F mark as displayed on the instrument. That way the multipoint errors are lessened by the combination of the two instruments together. Most would not notice the difference.

Then again, the certification means little if the certified instrument is not really accurate. Many certification houses only are certified to 1 or 1.5 percent. The cert is not that tight. So if the cert instrument is off by 0.9 it still qualifies and if the instrument that is calibrated is sold to be within 2% you could still be certified and calibrated and off 2.9%... This begins to become a really iffy game!

Here is a sensor that I pulled out of the shop. It has since expired (the calibration). However the sensor is not used much except in certain circumstances that I need to verify something. The error readings were on the calibration and I copied them onto the instrument for ease of use.

In looking over one the instruments that you had on the list (above) their accuracy was typically 2C (going from memory). That 2C could make for huge errors on the rH side as your instrument will reflect the temperature error in relative humidity. It is therefore important that the rH calibration, for example be done at a known calibrated temperature. This locks the relationship together.

You are not looking at a calibrated instruments here (MHO). You are looking at instruments where the manufacturing tolerances are NIST traceable, and that is not the same!

In this world of comparative instruments, I too get lost sometimes. I believe that it is more important to have precision and repeatability than accuracy. Accuracy helps you correlate two humidors, but taste and other human sensory data actually verify your settings, whatever they appear to be on instruments. JMHO!

59ad997834ca6_2017-09-0409_51_05.thumb.jpg.bd3416d773ede0a5669942a49cd6059c.jpg59ad996d8e4b4_2017-09-0409_51_26.thumb.jpg.2531b4cf3589c0ec6a37531334446c26.jpg

-Ray

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Correct me if I am wrong......so from my understanding I could essentially buy any"maybe not any" thermometer/hygrometer and send it to the NIST and have it certified by them (for a hefty fee) and that would be good for a certain period of time before needing to be re calibrated.... I could then us that thermometer/hygrometer to calibrate the rest of my instruments, which would in effect make them NIST traceable. So what I am looking at is an instrument that has been calibrated against an NIST calibrated instrument, and with each calibration down the step ladder one instrument to the next there is an increase in error ( all however NIST traceable) . I guess there is really no such thing as getting an instrument that would no longer need to be calibrated due to its profound accuracy with in a certain range. You obviously have a significantly higher understanding of this than I do, but want to make sure I'm understanding it correctly. I really appreciate the detailed, and thought out response. Cheers!

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To add to what Ray said, there is absolutely no avail for you to have a NIST calibrated or traceable (which essentially is the same, and you won't want to pay for fix-point calibrations)) instrument for: It's not for eternity! Understand that these devices just tend to drift over time, Sensors are aging, electronics is aging and instable. And finally, the resulting calibration curve will be temp.-dependent (but most calibs are done for a particular temp only), so how will the curve provided by an accreditation lab translate to your particular environment?

There is only one way and that is (as has come up in couple of threads meanwhile), regularly recalibrating yourself. There simply is no other way to get away with it.

The thing is, most electronic devices come with the same sensing core. So, my recommendation is, get the cheapest you can get (several of, that is, go redundant), and recalib. under your working temperatures about once year. That should more than do the job.

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12 minutes ago, Benzopyrene said:

I guess there is really no such thing as getting an instrument that would no longer need to be calibrated due to its profound accuracy with in a certain range

Exactly! Metrology is all about errors and uncertainties. There is no such thing as a "profound eternal accuracy". It is all a matter of scales and time. In science e.g. for certain tasks and parameters, sometimes you have to do calibrations each single working day.

Forget NIST (and NIST isn't doing the calibrations for you anyway, NIST is the national standard, like PTB or UKAS. They accredit labs that do the street work), all you need, is some simple instruments and a salt chamber or e.g. some decent boveda calibration kit.

 

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1 hour ago, Fugu said:

To add to what Ray said, there is absolutely no avail for you to have a NIST calibrated or traceable (which essentially is the same, and you won't want to pay for fix-point calibrations)) instrument for: It's not for eternity! Understand that these devices just tend to drift over time, Sensors are aging, electronics is aging and instable. And finally, the resulting calibration curve will be temp.-dependent (but most calibs are done for a particular temp only), so how will the curve provided by an accreditation lab translate to your particular environment?

I would say that this largely echo my sentiments. Getting a really accurate instrument is short-lived and an iffy proposition. Some form of self test appears to be a good idea, but unlike Paul, I don't have much faith in Boveda products. I say this because after reading white papers for their products, most have been 'bastardized' when viewed from the perspective as accurate 'instrument' for calibrations as far as I am concerned. I say this due to the fact that they are mostly blended, commercial friendly products that have dependence on thermal stability like many hygroscopic products. True aqueous salt calibration and testing needs to be done with pure salts in order to really provide the benefits of aqueous salt calibration. If you are going to follow this route, simply obtain the correct salts from a supplier and you will likely get better results.

As I have said time and time again. We all settle. Perhaps one day for the sheer sake of amusement I will purchase more accurate chilled mirror hygrometer test instrument. But in the real world for the cigar smoker, and that incudes one such as myself that is so hung up on cigar climatology; how could I rationalize the purchase of such an instrument when I could use that money to provide a decades worth of potentially fantastic smoking experiences, based on using my current storage methods? When the two are viewed as a one or another scenario, it makes no sense at all to pursue such folly... That dose not mean that I won't do it ... -LOL Just not today!

Cheers all! -Piggy

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17 minutes ago, PigFish said:

If you are going to follow this route, simply obtain the correct salts from a supplier and you will likely get better results.

I concur! There is also a flaw due to geometrical / boundary effects with boveda for calibration purposes (they are not strictly following the requirements for a salt chamber). But for ease of use, they might be the best or most practical way to go for most.

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43 minutes ago, PigFish said:

I . True aqueous salt calibration and testing needs to be done with pure salts in order to really provide the benefits of aqueous salt calibration. If you are going to follow this route, simply obtain the correct salts from a supplier and you will likely get better results.

 

Where can one obtain this?

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I use the Xikor system on Amazon. The system comes with the wireless remote sensors that are rated for - + 2% but you always want to check for yourself. I have 2 that are -2% and 1 that is -1%. So I add those numbers to the rh level I want which is 69%.

Hope this helps.

Tim

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Calibration has nothing to do with the ability of any sensing device to resist drifting. It simply is used to verify the accuracy of the of the process measurement. You could have 99.9 % accuracy for calibration, but still drift to say 90% accuracy a year later.

 

When I would use gas analyzers for coal power plant emissions, I would have to recalibrate every single morning for CO, O2, NOx, etc... using cal gases. These analyzers were worth thousands of dollars. For the gas analyzers I use now, and manometers, recalibration is required on an annual basis. With a store bought instrument, you're not going to get lab quality measurements.

 

I chose to simply buy a hygrometer that could take readings from several remote units. That way, I could monitor RH readings on every cooler without opening them. I would recommend recalibration for every unit on an annual basis if you are super anal, and note the bias. I am able to enter in a bias on the main receiver unit that I have, corresponding to the reading on each satellite unit. I honestly haven't recalibrated them in years. I simply go by feel and touch to verify proper water content. We are just storing cigars, not trying to grow microorganisms.

 

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I don't now much about cigars, but do know a bit about accuracy of electronic "things". As was mentioned, repeatability and precision are most important.

I only have one coolerdor right now, but use a raspberri pi to track temp and humidity with its own sensor. I also have two digital hygrometers from amazon in there that I monitor using a camera on the Pi. That way I can make sure all three sensors are reporting the same info, and I'll know when one of them needs calibrating, etc. the three sensors also report info from different "zones" of the coolerdor.

if I add another coolerdor, I will add more sensors to that same Pi so it can keep track of all conditions from all coolerdors.

i personally think it's best to add more average sensors than to go for one expensive one.

ps. If the Pi senses something wrong with the environment, it will send me a text. :)

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Personally, given that we are only storing/aging cigars, I honestly do not see a problem with 1 or 2 degrees inaccuracy, so long as I don't see many fluctuations and I am getting readings between 60 and 65, I am a happy camper.  If my Hygrometer is telling me 60, when it is actually 62, who cares?

 

I was using Calibre Hygrometers, retailing at £25 each, but now use multiple £6 cheapos from Amazon which look almost identical, other than cant be calibrated.  They are not as accurate, but a sticker with the variation written on does the trick.

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I use the sensorpush from Amazon. They are not pre calibrated but you calibrate them easily through the app. I replaced most of my hygrometers with them and haven't had any issues at all. I did have issues with the wireless gateway they sell. They sent me 3 different ones and none worked with a note 4, galaxy s8+, or a nexus 6p.

 

I did find that all of them were nearly spot on on the temp, and a +/- 1-3% on rh

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On 9/4/2017 at 11:47 PM, OB1 said:

I don't now much about cigars, but do know a bit about accuracy of electronic "things". As was mentioned, repeatability and precision are most important.

I only have one coolerdor right now, but use a raspberri pi to track temp and humidity with its own sensor. I also have two digital hygrometers from amazon in there that I monitor using a camera on the Pi. That way I can make sure all three sensors are reporting the same info, and I'll know when one of them needs calibrating, etc. the three sensors also report info from different "zones" of the coolerdor.

if I add another coolerdor, I will add more sensors to that same Pi so it can keep track of all conditions from all coolerdors.

i personally think it's best to add more average sensors than to go for one expensive one.

ps. If the Pi senses something wrong with the environment, it will send me a text. :)

I'm intrigued at this system you built.  Can you provide any more info?

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10 hours ago, Head83 said:

I'm intrigued at this system you built.  Can you provide any more info?

Sure. I used the following components added to a coleman cooler. The Pi and the relay are on the outside so they don't heat up the cooler. I started adding temperature control but it got complicated so there's no temperature regulation right now.

The Pi: https://www.amazon.com/gp/product/B01C6EQNNK/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Storage: https://www.amazon.com/gp/product/B010Q57SEE/ref=od_aui_detailpages00?ie=UTF8&psc=1

Power supply: https://www.amazon.com/gp/product/B019Q3U72M/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

Humidity+temp sensor: https://www.amazon.com/gp/product/B019MGIC3Y/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Fan: https://www.amazon.com/gp/product/B002KTVFTE/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1 (next time I'm going to get a higher speed fan)

Camera: https://www.amazon.com/gp/product/B013JWEGJQ/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Lights (used as flash for camera): https://www.amazon.com/gp/product/B00HSF65MC/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

Relay for turning on lights and fan: https://www.amazon.com/gp/product/B00E0NTPP4/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

There's also 65% boveda packs and a couple of digital hygrometers.

The Pi runs two routines:

1. monitor the temp/humidity and record them every minute. if something goes wacky, send me a text. At midnight, it emails me the days high/low temp and humidity.

2. Run a web server to show the temp/humidity graphs and take pictures. See attached picture. The spikes in the graph is when the fan turns on for 1 minute every hour.

The web server is accessible from the internet so I can take pictures all day at work. :)

 

Screen Shot 2017-09-08 at 7.36.54 PM.jpg

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