Although not strictly a Raspberry Pi project, I have a couple C.H.I.P. boards[1] scattered throughout my apartment collecting temperature and humidity readings (using a HIH8120 sensor[2]) and feeding it to my Raspberry Pi which runs InfluxDB and Chronograf[3] to store and display a simple dashboard. The end result looks like this: http://i.imgur.com/cIrhSUq.png
[1]: https://getchip.com/
[2]: https://sensing.honeywell.com/HIH8120-021-001S-humidity-sens...
[3]: https://www.influxdata.com/time-series-platform/chronograf/