I bought that unit to play with and also bought the temperature and humidity sensor.  Have not done anything with it yet but was going to hook to fan control on a bin for automatic shut off or on depending on my manually looking at an equilibrium chart for the stored grain and deciding what to do.  I would like to make it automated but for the money it was a challenge to try.  I bought off of ebay Sonoff TH16 Smart Wifi Switch Monitoring Temperature Humidity Wifi Smart Switch

stepsgms.com has a product that looks very similiar.

I would like to see how others have tried it out - cheap unit.  Just have to use an app from overseas to control it for free from what I have found unless I could be creative and find another controller.