I ordered a few by accident from AliExpress and they showed up yesterday. I don't know for the life of me what to do with them. I was thinking maybe as a temperature/humidity monitor thing, but it would have to be mains powered because I don't think there's a way to make a device like this diy'able (with arduino and dht22 level components) and make it run off a battery for more than a few months. So any suggestions are good.