Depends on your definition of `cool'; here's a multi-zone Smart thermostat... https://joetruncale.medium.com/thermos-d089e1c4974b https://joetruncale.medium.c

Depends on your definition of `cool'; here's a multi-zone Smart thermostat... https://joetruncale.medium.com/thermos-d089e1c4974b https://joetruncale.medium.com/thermos-d089e1c4974b a smart cat flap... https://github.com/gerrito333/mousehunter-edge/blob/master/README.md https://github.com/gerrito333/mousehunter-edge/blob/master/R... and a meteor detector! https://www.skyatnightmagazine.com/advice/diy/raspberry-pi-meteor-detector/ https://www.skyatnightmagazine.com/advice/diy/raspberry-pi-m...