Not to thread-jack, but the Sonoff devices with DHT11...how do those work? I built an attic fan controller years ago based on an Arduino, 3 DHT11, and 2 XPS3 switches. The device works great for what I wanted (ventilate for x time if humidity is too high and outside is lower and within temperature range, ventilate if temp is too high). I can control it remotely if it gets stuck since the fans are on X10. But, it sometimes runs at night (rarely) and I have no way to see what it's doing over time (it doesn't transmit activity). If I were to redo it, these seem like an awesome option!