I figured I’d share here since I couldn’t find it documented anywhere in my google searching. But I was able to make ESPHome fallback to a local temperature sensor instead of using a home assistant provided sensor using a template sensor with the following code where active_temp is a value that either contains the home assistant value if available or the local value if not. I haven’t tested without home assistant online yet, but with unplugging the mbr_temp sensor remotely I can confirm it switches back and forth!
The lambda of the active_temp sensor is doing all the heavy lifting, the isnan function is checking to see if it is not a number, as that’s what it returns once it becomes unavailable, if it’s not a number then it changes the value to the fallback sensor.
- platform: homeassistant
id: remote_temp
entity_id: sensor.remote_sensor_temperature
filters:
- lambda: return (x - 32) *(5.0/9.0);
- platform: dallas
address: <address>
name: "Utility Room Temperature"
id: utility_room_temp
- platform: template
name: "Active Furnace Input Temp"
id: active_temp
lambda: |-
if (isnan(id(remote_temp).state)){
return id(utility_room_temp).state;
} else {
return id(remote_temp).state;
}
update_interval: 20s
I’m using this for a fully local thermostat on the esp that has the temperature sourced remotely. But I’ve had issues where home assistant locks up and then causes the A/C or the Heater to hang on or not turn on and I needed a fallback that was local to the ESP.