Was looking at some kitchen supply stuff and saw this online and on sale and thought that it would be great in the humidor. I haven't used it but I have been really impressed with their other products. Their folding cooking thermometers are the standard in professional kitchens.
http://thermoworks.com/products/humi....html?whence=#
Not sure if this is the right forum for this. I am not associated in any way with the site so not a sales/vendor item.