Planet Waves Humiditrak

[FLATROCK HILL]

I would simply be very cautious about relying on any cheap humidity sensor. Accurate sensors still cost money. You get what you pay for. The cheap sensors may give you an approximation, but like cheap thermometers, accuracy can be all over the place and there is often very little consistency from one example to another.

My humidity sensor must be a good one. It was a gift. It came along with a matching thermometer and barometer. All three instruments are beautifully gold-plated and mounted in an ornate piece of carved and stained oak.

The hygrometer says the room is at a comfy 45% humidity. I just can't figure out why sparks are jumping off of the cat's fur whenever I pet it.

[almeriastrings]

2) It isn't really necessary to get the relative humidity right to within any better than 10-20%. So the less expensive meters, which can easily by off by +/- 10% or thereabouts from the true value, are still perfectly good for the purpose of keeping your instrument's humidity in roughly the right range. A digital meter can be had for less than $10 that fits the bill, in fact.

The problem is that they can be far worse than that. In an unconnected field (wildlife biology and animal husbandry) I measured a whole bunch of these things, as the exactly same sensors and internal electronics are used in vivarium meters, etc. I used two recently calibrated FLUKE lab grade meters as reference. The results were frankly scary. We had cheap (<$15) meters reading RH of 41% when it was actually 23%! We had others showing 45% when in reality it was 25%... they were all over the place. With an animal that can lead to dehydration and renal failure. With mandolins, at least the worst you can expect is a few cracks...

[Jeff Mando]

I find that hard to believe......I guess the cheapo humidity gauges haven't caught up to the accuracy of the (inexpensive) Snark tuner or the dollar store quartz watch, yet! Which everyone knows is just as accurate as a $10K mechanical Swiss watch, but certainly not as pretty!

[Stevo75]

It's easy enough to get a cheapo and validate it. Put it outside and check the local humidity on NOAA, Weather Channel, etc.. Do this a bunch of different times at different RH levels. Then you'll know if it reads a little high, a little low, etc...

This works fine out here on the high plains where the weather is very consistent. The local airport where the weather station is located will not have different conditions than outside my house. If you live in an area with varied terrain, this might not be reliable (for example, if you live in a different valley than the valley where the weather station is located).

[sblock]

How about a digital humidity meter (hygrometer) small enough to fit inside the compartment of your case (small than a micro tuner, in fact), and which nominally gets the relative humidity right to within 1%, according to its published specs, but only costs $6.50 -- with free shipping? In actuality, it's probably about 4-5 times worse than that (i.e., 4%-5% accurate), but that is still plenty good enough for seeing if your instrument is properly humidified. Oh, and it tells the temparature, too! It's the Model TN-4, found many places online, including here. (This website lists the dimensions wrong: when they say "cm", they really mean "mm"!! This thing is under 5 cm wide.)

At that price, it should be a stocking stuffer for every musician.

But if you want something that's much more accurate -- but larger, perhaps to place in the room, but not inside the case -- and yet only 75 cents more (!), try this.

You could get both for about the price of one set of mandolin strings.

NFI.

[FLATROCK HILL]

Thanks sblock, Just ordered the larger one you linked.
The fancy gold plated gauge in my music room is suited better as 'decor' than a useful instrument. Hopefully this new one will offer better information!