Hashyanswered grow question 10 months ago Just to add the app is free and I bought WiFi plugs and sensor from amazon, I think the plugs are about £10 each and the sensor was about £25. I use a few plugs, 1 for my light, 1 for radiator, 1 for Dehumidifier or humidifier depending on stage of the grow, 1 for radiator, 1 for Extractor, 1 for fans, 1 for my automatic feeding schedule. Very handy to have as I can access my system anywhere.