Track sensor last update

ESPHome
1

Hi,

I have an espdevice which tracks the power consumption and everything seems to work fine, except that the battery fails unexpectedly. Since I can not add a monitor the battery I wanted to track the last update of the sensor.

Is there a way to set a timestamp of the last update es value to use in an automation ?

Thanks

2

Add the esphome status sensor and trigger when this binary sensor changes to off:

3

Thanks for the suggestion, however I am thinking of using deep sleep in the future which would mean I get an offline every time the sensor goes to sleep. Therefor I thought I could somehow access the information when the data was last updated, e.g. as
in the history.

Screenshot 2022-03-23 at 10.51.15
Screenshot 2022-03-23 at 10.51.151622×1076 85.9 KB

4

That’s going to have the same issue. The sensor is not going to update while the ESP is asleep, it will change to unknown and stay that way.

You could do a for state trigger just longer than your max sleep time if the sleep period is timed. e.g. if you sleep for 5 minutes:

trigger:
  - platform: state
    entity_id: binary_sensor.energieverbrauch_status
    to: 'off'
    for: '0:05:10' # sleep time + time to wake and connect
1 Like
5

You can access that information,
states.<sensor_name>.last_updated, states.<sensor_name>.last_changed

Be aware though if you use it to create a sensor or a trigger, it wont update on its own, you might need to create an automation to trigger its updates. As a condition it works fine. You should also use defaults as using the states entries, they arent well filtered so can cause non-expected data types.

People probably wont like this solution, but I use it for exactly what you want and I dont believe there are other good options.

e.g.

      button_bedroom1_bedside_lost_contact:
        friendly_name: 'Button Bedroom1 Bedside Lost Contact'
        value_template: "{{ (states('sensor.now_timestamp_hour') | int(default=0) - as_timestamp(state_attr('sensor.button_bedroom1_bedside_battery','last_seen'),0) | int(default=0)) > 345600 }}"
6

Which is not going to change if the device is asleep. Also it is far easier to use for than doing math with datetime objects.