[joshefin]

I used RuuviTags (https://ruuvi.com/). They use a battery and send data over Bluetooth to your mobile phone.

[glogla]

You only get data from those when the phone is in bluetooth range. That's not very useful for long-term measurements. Unless you buy cheap android phone as a basestation I guess.

[lemming]

I have a bunch of SensorPushes at home which do the same, but they store the data for up to 20 days iirc, so it's effectively continuous data unless both my wife and I go away for a month or so.

[throwaway9d0291]

It's popular to set up a Raspberry Pi or similar to act as a bridge between Bluetooth and wifi.