I would flash it with Tasmota, but these sensors are cheap/awesome: https://www.amazon.com/Sonoff-Temperature-Humidity-Controller-Appliances/dp/B075FSHKQ5/ref=s

I would flash it with Tasmota, but these sensors are cheap/awesome: https://www.amazon.com/Sonoff-Temperature-Humidity-Controller-Appliances/dp/B075FSHKQ5/ref=sr_1_1_sspa?hvadid=78134099057334&hvbmt=be&hvdev=c&hvqmt=e&keywords=sonoff+th16&qid=1575083424&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExUFVKQTFCSTRDTjZLJmVuY3J5cHRlZElkPUEwOTUzNjQ2MVYwRVY5NUlWQzg4UyZlbmNyeXB0ZWRBZElkPUEwNTI5ODQzMVhNOFJPSDlBNFhTUSZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU= https://www.amazon.com/Sonoff-Temperature-Humidity-Controlle...