TEMPer Hum USB Hygrometer and Thermometer

I’ve had the opportunity to play with quite a few wacky USB devices in the past few years via my other website The Gadgeteer. Everything from a USB refrigerator and a USB drum kit, to a USB letter opener. The latest interesting USB gadget to show up on my door step is the USB Hygro-Thermometer fromBrando. This flash drive sized device can measure both temperature and humidity.

I actually asked Brando to send me this device for review because I am concerned about my small but growing collection of ukuleles. As we know, these small wooden instruments are sensitive to humidity levels. Several weeks ago I noticed that one of my ukuleles had developed a nasty split on the back. This is something that I’ve never had happen in all the years that I’ve had guitars, banjos and dulcimers in my house. I already keep a small inexpensive hygrometer in each of my uke’s cases. Typically, for wooden instruments, you do not want the humidity levels to drop below 45%. Whenever I check the hygrometers in the cases, they usually read in the 50-55% range, so I thought I was fine. Then the crack appeared on the back of my Koa Pili Koko uke, even with the hygrometer showing that the humidity level in the case was 60%. Grrrrrrr. It was time for a digital hygrometer…

The TEMPer Hum from Brando is a regular USB flash drive sized device that has several small holes drilled in the sides and top to allow it to measure temperature and humidity.

Here is the TEMPer Hum next to one of the inexpensive non-digital hygrometers that I keep in each instrument case. As you can see by the reading on the non-digital hygrometer, the humidity is approximately 56%. To see what Brando’s digital version measures, you first have to install a small Windows application that is included on a mini CD. Unfortunately for me, there isn’t a Mac version of the app. You also have to download and install .Net framework from Microsoft’s site before you can start viewing measurements.

Click thumbnail to see full-size image

Once the application is installed, just plug in the USB TEMPer Hum and click the Start button to start recording data. You can view it in Celsius or Fahrenheit.

Right away I was totally confused by the temperature and humidity readings that this device was displaying. It showed that the temperature down in my basement office (where I keep my ukuleles) was 86 degrees. Ummm, there was no way it was that warm in the basement. It also said that the humidity was only 33.55%. That was wildly different than the 58% reading from the other hygrometer. At first I thought maybe the problem was the fact that I plugged the TEMPer Hum into a USB slot on the back of the notebook computer. Maybe it was reading heat from inside the computer… So I used the included USB extension cable. Unfortunately, that had no noticeable effect. So which device was correct? The TEMPer Hum or the analog meter?

To find out, I decided to go to Radio Shack and buy yet another digital Thermometer/Hygrometer device, so I could have a third ‘opinion’. I plunked down $20 for a model #63-1032 that you see in the image above. I also brought down another thermometer to add to the mix of measurements. Here’s what they measured:

TEMPer Hum: 33.86% / 86.01F
Analog hygrometer: 48% / (doesn’t measure temperature)
Radio Shack thermometer/hygrometer: 43% / 73.6F
Oregon Scientific Thermometer: (doesn’t measure humidity) / 72.3F

As you will notice, the humidity readings are considerably varied… so much so, that I have absolutely no idea which one (if any) is measuring correctly. I’m not sure I really trust the Radio Shack device since it has both indoor and outdoor temperature sensors and both are in the exact same room and both are showing different results. Go figure.

So the conclusion to this review is that I really can’t recommend the TEMPer Hum USB Hygrometer / Temperature sensor. I know for a fact that it doesn’t measure temperature correctly, and that leads me to guess that it doesn’t measure humidity correctly either. In the mean time, I will hope that Radio Shack and analog hygrometers are accurate enough to trust. As long as one or the other doesn’t drop below 45% for any length of time, I’ll hope that humidity levels are safe enough to protect my wooden instruments from cracking.

What do all of you use to measure humidity for your instruments?

14 Responses to “TEMPer Hum USB Hygrometer and Thermometer”

  1. I’m surprised that the Koa Pili Koko cracked. It was supposedly built in a humidity controlled factory in China.

    Anyway, for humidity reading, most of my cases have a cheap “Springfield” thermometer/hygrometer I bought at Wal-Mart for like $7 each. The humidity reading between them seem to vary by about 10-15%. I also have a couple of thermo/hygrometers specifically made for instruments and a couple that comes with the Ameritage case. All of these return different humidity measurements, but they are more or less within 10-15% of each other, so I get a general idea of the humidity in my cases. I don’t think the instrument-specific hygrometers are any more accurate than the cheapos.

    I think the best you can hope for is to get a rough idea of the humidity and put plenty of humidifiers in the cases during the winter. Hope that helps.

  2. I’m thinking that the crack in the uke was due to a weak place in the wood, and not humidity…

  3. Sorry to hear it cracked; that can be heart breaking.

  4. There was a happy ending though… MusicGuyMic allowed me to ship him the cracked uke and he sent me a brand new one in its place. They have a 1yr warranty. 🙂

  5. Hi again, Julie,

    Too bad about the TEMPer Hum and thanks for keeping me from buying one. Clearly, that’s WAY off but I think your experience with your other instruments is pretty typical. I’ve found that thermometers are usually pretty close but hygrometers vary widely. My experience has been like Georges, a 10% 0r 15% variation is pretty typical, sometimes more. A couple of years ago I bought three hygrometers for my ukulele cases, ones that are intended for cigars. All three read ~20% low. Before I retired I took one of my “good” hygrometers, a Honeywell, to work and had our aerospace gage lab calibrate it. They couldn’t actually adjust it but they did tell me it’s off by 5% at 50% RH. Assuming it has stayed constant over time (maybe not a good assumption), I can at least factor in that 5% and know what the actual RH is in my “ukulele” (nee dining room) room.

    However, I think there are two things going one here. One is that it’s a Good Thing to keep the RH where your ukes live reasonably constant. It’s not so much the RH itself but wide swings that will crack the wood. That said, the other factor is how different your mean RH is than the place where the ukulele was glued up. If George is right and your Koa Pili was built built in a humidity controlled factory in China it shouldn’t have cracked (unless the wood wasn’t properly dried in the first place). Like you though, I had one nice ukulele (a Mele concert pineapple) crack even though I ALWAYS kept it humidified. And when I posted about it I heard from others who had the same experience with Meles. My conclusion was that the environment Meles are built in is just too humid and therefore too different from my home in the Northeast during heating season.

    Glad you had a happy ending.

    PS – I’m enjoying your Boat Paddle series and looking forward to Jerry starting my BP concert.

  6. Have you tried the Oregon Scientific USB Indoor Outdoor Thermo Hygrometer?
    I would be greatful if you could review it for me.
    ps I’m a wood floor installer I don’t murder ukuleles.

  7. wood butcher:

    Do you mean the same one that I show above in the last picture?
    I use this in my office, but haven’t reviewed it. I’ve noticed that all the hygrometers that I own show different results – which is frustrating because it’s hard to know which one to trust (if any).

  8. I don’t think the one in your picture is the same one as I have found here;


    and other places too.

  9. No I don’t think its the same model,if you search google for: Oregon Scientific USB Indoor Outdoor Thermo Hygrometer you’ll find the one I’m referring to.

    Can you plug your Oregon Scientific into your USB?

    I think it would be handy to have a device that logs the temp and humidity throughout the day. As its the average humidity that will effect any wood, not just what the hygrometer says when you happen to check it.

  10. I went out to my local cigar shop and got their run-of-the-mill digital hygrometer for about 15$. No calibration needed (unlike the analog ones) and worked right out of the box. I tested it by placing it on a dry stand in a tupperware box that had a water/salt mix in the bottom. Close the lid and let it sit for a few hours, then check the reading and it should be about 70%.

  11. USB Fan

  12. Actually salt should give more like 75% RH, but if it’s correct at 75% will it be correct at 45%? The answer is no, as I’ve found by checking three hygrometers: with salt water they read 75%, 78%, 85%, and in room humidity they read 43%, 29%, 32% — the two that were higher in the salt water test were (much) lower at room humidity. It turns out you can do a 2-point calibration using a different substance to give a controlled 33% RH. I might try that.

  13. I have need of humidity readings and recently bought 6 identical springfield digital thermometer/hygrometers for $6.47 each from walmart, mostly to test veriability and accuracy of inexpensive hygrometers. The veriability turned to be only 10% from highest to lowest, which led me t the question of which one was closest to correct , without having to go to some science lab or buy a really expensive hygrometer? While searching for even cheaper hygrometers ( I want to give them away to my customers) I found a $3.99 hygrometer calibration kit at a cigar store called cheaphumidors.com that is a bag containing some material that creates a 75.5% RH and is reusable. At that price I decided to give it try – soon I should be able to calibrate all my 11 different hygrometers

  14. What can hurt the musical instruments is not only low humidity but also the sudden change of humidity.

    Thanks for the information about USB hydrometer!!!

Leave a Reply