I know this topic has been brought up several times...this piece seems to do it all.  Little pricey ($199) but damn cool and rated well.  

 http://www.elertus.com/

Hopefully more manufactures get involved and it drives down the price.  I keep three large humidors so buying three let alone one is hard.  But it is good to keep up on the technology.

Sounds cool but agree that it's pricey

Oasis has nifty new units with built-in wi-fi. They were mentioned in a recent post.

These are just sensors? Not actual humidifiers?

The longest I leave mine unattended is about ten days so, I don't find these things necessary for my peace of mind. I just make sure everything is freshly filled or charged before leaving town and have yet to come home to find a problem........

QuoteconditionZero - 1/29/2014  12:26 PM  These are just sensors? Not actual humidifiers?

 Correct just sensors...

Build one yourself for about $75.  Instructions on for arduino version assembly and web page setup...

http://learn.adafruit.com/wifi-weather-station-arduino-cc3000/introduction

Might not look pretty, but could easily hide inside a humidifier brick.

Same sensor, but instructions for Raspbery Pi and output to Google Docs.

http://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/overview

I've got a handful of RPi's, I might try to re-purpose one over the summer. If I had a walk in humidor, this would be a no brainer.