You can get hygrometers in pet shops, department stores (whatever department things like air conditioners are in), amazon, ebay..  The one you see in the pics here is from a pet shop.  The brand is "All Living Things".  It was 8$ or 9$ for a matched set of hygrometer and thermometer.  You can find them cheaper than that, if you look around.  But this set looks nice (in my opinion), and I was looking for a nice set of analogs to build into my violin case.

Problem is, with what I've learned about violin cases lately, I may want to just build a better violin case in the first place.

"DIY or pay through the nose" is the way it looks to me with cases (and many violin accessories).  I am not by any means the only DIY spirit on this forum, though.  There are some very talented and creative folks here.  I'm just the member who maybe does more of the low budget projects. LOL

I think you'd want to use a little larger pill bottle (or whatever container) for a viola case.

I haven't noted the marbles sweating.  But I can't guarantee they might not, under some circumstances.  Every time I've opened the case, I've tried to shake water out of the bottle though, and gotten usually nothing.  Right after they'd been wetted, I got maybe a drop or two.  So it doesn't seem likely they'll leak all over the case or anything.

I haven't done any sort of a permanent or travel mount with this because it was more of a "proof of concept" project to see if the marbles/balls were workable in a case humidifier.  But it wouldn't be hard. Stitch or glue in a little velcro or an elastic loop.  Cut a little piece of metal and bend it into a clip to hold the bottle and screw it to the inside of the case someplace where the bottle won't bang against the violin when carrying it.  Maybe cut a hole in the side of the accessory compartment so that the bottle could be in the compartment and the cap with the holes open to the inside of the case.  There's a lot of ways it could be done.

I am still researching the idea of cases and giving some thought to how one might go about building one.  But some thoughts in progress..

Well, most of the surviving antique cases I've seen pics of were wood or sometimes wood covered with leather.  That they survived, and presumably the violins inside them did as well, is a piece of data.  More modern materials may be better in at least some specific regards or even overall, but we don't have a century or two of durability testing on them yet.  

http://thecanadasite.com/image.....eydcl2.jpg

Finished wood or wood with leather over it will breathe a bit, as you mentioned.  Wood isn't hugely expensive (assuming one stays away from the very exotic stuff), so I've been tending to favour wood and the older "coffin" design where the violin rests on it's back in the case when it is being carried rather than the "on the edge" more often used with modern cases.  I don't know if it is actually better, but violins survived the 1800s in them, at least.

To be fair though, even the cheaper modern cases might last a century or more, for all we know.  The data just isn't in yet. 

I'm not sure what they used for support and padding.  I know that at least way back violinists often used old clothes or any sort of rags to pad the instrument in the case or box so it didn't get knocked around.  

So at least at this time, my thoughts would tend towards wood and some violin-friendly material as the lining.  I haven't gone much past that on design contemplations yet. 

I'm not so sure about rubberized cloth as a permanent part of it, for the reasons you already mentioned.

I have also given some thought to if it might be possible to upgrade the standard cheapie case that comes with the usual beginner violin to make it not optimal, but better.  Since that is what I currently have, and a lot of people have them as well, that has been what I have given the most thought to.  A lot could be done to improve those by lining them with something more violin-friendly than acrylic plush, and building in a hygrometer, a place for a humidifier of  some sort, and perhaps a thermometer.

One could skip over re-lining it, if one made a bag to keep the violin in, inside the case that was of a material that would be a bit kinder to the finish and that would moderate humidity and temperature a bit.

http://www.arc-verona.co.uk/do.....790100.jpg

Ok, since somebody is sure to ask.. "What is wrong with acrylic/synthetic plush?"  Get a piece of it and find a car that has just been waxed.  on a sunny day, polish the hood of the car with the plush.  It will "fog" the wax because it leaves a lot of little tiny scratches.  It will take longer to fog varnish, but it will eventually manage it.  I've seen it on plenty of old guitars over the years.  (Yes, guitars have a different finish than violins, but the principle remains the same.)

But a bag wouldn't need to be silk, necessarily, either.  Cotton would also be nicer on the finish than acrylic, and also will moderate humidity and temp, though to a somewhat lesser degree.  So one could make a bag out of an old and worn favourite cotton t-shirt, rather than throwing it away.  Guitarists have been using pieces of old t-shirt for a long time for polishing guitars.  They work reasonably well for it.  It is a soft cloth and fairly lint free.

So the easy upgrades for the common inexpensive no-frills case that come to mind would be a bag for the violin (or viola) inside the case, some sort of a humidifier, and a hygrometer.  That's what I can think of so far.  

The not-so-easy "deluxe" option for DIY would be to make a case from scratch.  Which still probably wouldn't cost as much as buying even a reasonably priced better (meaning anything costlier than what comes free with a beginner violin kit) case.

So there's at least some thoughts on cases and upgrades.  Not enough for a definite plan or project... Yet.  LOL

We had a bit of a cold snap here last night.  Temps outside dropped suddenly and snow fell and the humidity indoors dropped to around 20-25% for several hours.  That was with a couple of vaporizers pumping over a gallon of water each out into the air, since this is a rather old and drafty house.

But when I opened my case to play the acoustic violin a bit, humidity in there was fine, low 40s.  I wasn't thinking and left the case open while playing, so it dropped a bit more than it needed to, down to about 30%.  Putting the violin back in the case and closing it, I checked it after about an hour and it was almost up to 40% again. 

Impressive and useful enough for a 1$ case humidifier.  LOL

An hour or two in low humidity while it is being played isn't likely to hurt a violin, I don't think.  Wood (especially finished on the outside surface) loses moisture slowly.  It would probably take a few days to get dehydrated enough to risk cracking and etc.  (I think.)  Using a hygrometer shouldn't be another gadget to panic over, just a heads-up sort of thing to let one know when the conditions in the environment the instrument is kept in are going outside of what is good for the instrument.  "An ounce of prevention is worth a pound of cure", since repairs or replacement of any instrument costs a lot more than using a little common sense in taking care of the instrument in the first place. 

Interestingly, I noted today that the water marbles had "shrunk".  I had almost filled the bottle with them, and it only appeared about 2/3 full.  So I topped the container up with water and let it sit for about 5 min until they were back to full size, then poured out and shook out all the water I could, to avoid any drips or leaks. 

For a dollar store sort of item, I do like how the liquid marbles work.  Better, I think, than the sponges I used to use.  Those sometimes got a sour smell or mold over months of use, and were more prone to making the section of the case they were in actually a little damp, if I didn't get enough water out of them.  I was hoping to avoid those issues with this project, since I think the violin is maybe a bit less robust than things like acoustic guitars.  Besides, it is bad enough to have to "air out" a guitar because the case got a funky smell from a sponge that went sour, but you don't play a guitar by putting it next to your face. like you do with violin.  LOL

The one thing that I've noticed about anything like this is that the expert views tend to vary a lot.   Where I bought my violin from, they say 40% to 50%.  Fiddlestix's expert says 41%, if I recall right. 

I don't know for sure, but I like the sound I get out of the instrument at over 40% better than under 35%, so I think there is some difference.  Maybe it isn't the same for every violin or climate.  Maybe the wood gets used to lower humidity or just needs to be set up right to sound good.  I don't know for sure, still too much of a noob at all this with violins. 

I don't notice as much difference in acoustic guitar sound with humidity change as violin, though, I can say that much.