Automatic Humidity Fan
Automatically turn on a fan when humidity is high (ex. showering); automatically turn the fan off when humidity lowers - using Home Assistant and Node-RED.
Requirements
Node-RED

[{"id":"32c50907.2cde1e","type":"stoptimer","z":"9afdaf1d.9b88f","duration":"5","units":"Minute","payloadtype":"num","payloadval":"0","name":"Wait 5 Minutes","x":620,"y":200,"wires":[["cdfbf50a.3eecc8"],[]]},{"id":"cdfbf50a.3eecc8","type":"api-current-state","z":"9afdaf1d.9b88f","name":"High Humidity?","server":"a77b5e9d.0c69","version":1,"outputs":2,"halt_if":"70","halt_if_type":"num","halt_if_compare":"gt","override_topic":false,"entity_id":"sensor.bathroom_humidity","state_type":"str","state_location":"payload","override_payload":"msg","entity_location":"data","override_data":"msg","blockInputOverrides":false,"x":280,"y":320,"wires":[["7e082343.a7f13c"],["c5c47556.bb3f8"]]},{"id":"c5c47556.bb3f8","type":"api-call-service","z":"9afdaf1d.9b88f","name":"Turn off fan","server":"a77b5e9d.0c69","version":1,"debugenabled":false,"service_domain":"switch","service":"turn_off","entityId":"switch.bathroom_fan","data":"","dataType":"json","mergecontext":"","output_location":"","output_location_type":"none","mustacheAltTags":false,"x":610,"y":320,"wires":[[]]},{"id":"7e082343.a7f13c","type":"stoptimer","z":"9afdaf1d.9b88f","duration":"1","units":"Minute","payloadtype":"num","payloadval":"0","name":"Wait 1 min","x":610,"y":260,"wires":[["cdfbf50a.3eecc8"],[]]},{"id":"43927abd.48ee2c","type":"server-state-changed","z":"9afdaf1d.9b88f","name":"High Humidity","server":"a77b5e9d.0c69","version":1,"exposeToHomeAssistant":false,"haConfig":[{"property":"name","value":""},{"property":"icon","value":""}],"entityidfilter":"sensor.bathroom_humidity","entityidfiltertype":"exact","outputinitially":false,"state_type":"str","haltifstate":"70","halt_if_type":"num","halt_if_compare":"gt","outputs":2,"output_only_on_state_change":true,"x":90,"y":200,"wires":[["595cf5bf.3e5e34"],[]]},{"id":"595cf5bf.3e5e34","type":"api-call-service","z":"9afdaf1d.9b88f","name":"Turn on fan","server":"a77b5e9d.0c69","version":1,"debugenabled":false,"service_domain":"switch","service":"turn_on","entityId":"switch.bathroom_fan","data":"","dataType":"json","mergecontext":"","output_location":"","output_location_type":"none","mustacheAltTags":false,"x":310,"y":200,"wires":[["32c50907.2cde1e"]]},{"id":"a77b5e9d.0c69","type":"server","z":"","name":"Home Assistant","addon":true}]
Copy the above, import into Node-RED, configure the nodes, and deploy the workflow.