Sensor not updating when same value received

Configuration
1

Hi there,

I have a Konnected Pro module with a DHT temp sensor connected to it. This is feeding in to HA via the Konnected integration. I have it configured to send an update/event every 1 minute.

The issue I have is that HA is not updating the sensor’s last_updated value if the temperature value has not changed, even though the module is sending a new event/message every minute.

I can see the the event is being sent to HA (I have enabled debug - homeassistant.components.konnected.handlers). So why isn’t HA updating the sensor entities attributes?

Thanks,

J.

2

If the state changes, last_changed is modified
If the state or an attribute is modified, last_updated is modified.
If there is no state or attribute changes, neither is updated.

3

Hi,

So in my case (as the sensor doesn’t have any dynamic attributes) when the value/state stays the same, HA will think it hasn’t received an update?

Any idea how to fix this? I have tried the update_entity call, but that didn’t work.

The Konnected handler is detecting the update, it appears it’s the rest of HA that is ignoring it.

4

There is no fix, it works as designed. If updates are sent without any actual changes, the last_* won’t be changed either.
What are you trying to achieve?

5

Hi again,

Maybe I’m trying to be too clever, but I have an automation that checks HA to see if it hasn’t been updated by a sensor in a set period, it then generates an alert/notification.

I do also check for the sensor being offline too.

Ps - In my simple mind the design/logic/use of last_changed and last_updated seems wrong. I would have thought last_updated should be updated even if the values are the same, last_changed should be used for when a value actually changes. The temp sensor doesn’t have any attributes that change, so with the current design I believe the two timestamps will be the same. If necessary there could be another time stamp variable used for attributes.

6

Saving the same data over and over again is quite pointless.
It just takes up space and eats on the write cycles on the memory cards/SSDs.

7

Bump. I have this issue as well. Currently I can’t see if I am still receiving the same value, or if my sensor has died (which happens a lot with various integrations).
This is an issue with some graphing cards as well, as they just continue on charting a line even if the sensor is dead.
Is there a solution to this??

8

Here is a use case where it makes sense:

I keep track of the number of hours my heating system runs. From that I can calculate my fuel consumption as I know the average consumption per hour. My set up is as follows.

  • I have a sensor.runtime which is updated every day with the daily value. This sensor is updated through MQTT.
  • I have a utility meter
utility_meter:
  runtime_since_refill:
    source: sensor.runtime
    name: Runtime since refill
    delta_values: true
    tariffs:
      - basic

Now if the sensor.runtime does not update, my utility does not update either. So those days are not taken into account in the calculation.

9

You got me…
There is no integration that can do that.

History Stats - Home Assistant (home-assistant.io)

10

Actually (and sorry forgot to mention that in my update) there is. As I use MQTT I can define force_update: true for MQTT (binary) sensors. But if it were an ordinary sensor, you’re correct.

11

You didn’t click on the link did you?

12

I did, :grinning: but I does not solve my case where I need the sum of a set of sensor states. The runtime sensor returns values like 1.03, 2.11, 2.11, 3.0. After this sequence the runtime_since_refill sensor should be 8.25 not 6.14. So using a state does not really work. I do not get state changes, I get how much work the system did.

Secondly, my current solution takes network issues and HA downtime into account (I use a mail account to buffer information). But that is specific to my situation.

Thank you for your reply btw