Humdity Meter For Filament Storage

Can anyone recommend a Humidity Meter that is accurate to find out when to recharge silica gel used to store filament. I have been searching online for a long while and cannot find anything that doesn’t have a fair bit of negative reviews saying they just don’t work or are crap.
So if anyone is using one they got from Amazon or some other site.


This is what I use…
When it indicates, just plug it in and it dries itself.

Heard about it, saw quite a few reviews reporting ineffective units that don’t really reduce humidity and don’t dry after being plugged in for a while (or at least the indicator failing to change color). Also a few reviews mentioned burning of the product and the stuff touching it while recharging (I assumed this means they use cheap components that might work OK but might burst into flames while I leave it to charge… kinda a high risk to take when compared to putting silca gel beads in the oven). Also in general any silca gel component that changes color based on humidity is using 1 of 2 materials, one of which is regarded as toxic and potentially carcinogenic (cobalt chloride) and the other is also toxic (methyl violet) so if the enclosure breaks for some reason you got a bunch of potentially hazardous materials (in this case its methyl violet which is slightly less toxic but still…). I would prefer just gen clean white silica gel and avoid and fire hazards with something ill be handeling so much…

You can use something like that without the particle sensor.
Add Monitoring and alerting and you are done.

I’ve been using two of the Eva-Dry in the filament chamber of my enclosure for some months and have absolutely no issues through 4-5 rechargings. Just bought 2 more to use in storage boxes.