In case this helps someone in the future, I learned two additional things about getting these added to Home Assistant: The "file does not exist" error messages is because I had not created a sensor yet. Described here: https://community.home-assistant.io/t/mysensors-persistance-file/11047 Home Assistant was not seeing my RelayActuator sensor because it needs to send an initial value from the loop. For some reason, that is not in the example sketches. Mentioned here https://www.elektormagazine.com/labs/mysensors-home-assistant-howto and I used code from here to make it happen https://www.home-assistant.io/integrations/mysensors#presentation