I’m looking for suggestions for low cost, battery powered temperature sensors. I will be placing these inside a few HVAC ducts to monitor supply and return air temperatures, so I won’t have any ways to run power to them. I looked briefly into the ESP8266 system, but it seems battery life would be an issue since it is wifi based.
I’ve also looked into some of the 433MHz stuff, but don’t have much knowledge of it. It seems with the 433MHz stuff I’d be pretty limited in how many sensors I can utilize as it doesn’t appear that they have unique IDs that they broadcast with.
I’ve been looking at the xiaomi stuff. Its not dirt cheap, but they are probably the cheapest non-DIY option out there. $26 for the gateway and then $9/sensor. Still would add up, though.
I do like your idea of monitoring HVAC ducts. I’m going to have to do that.
I just came across the xiaomi sensors yesterday. I have a HUSBZB1 zwave/zigbee stick. I wonder if I could pair the xiaomi sensors directly to the stick instead of using their hub.