Automation on Numeric Falling Edge

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1

Hi, I would like to trigger an automation on the falling edge of the Active Power of my dryer. The Active Power is being measure by a smart plug and stays around 1000W in normal operation and I would like to detect when it goes to 0.
Anyone has any idea how can I resolve this?

2

The trigger should be like this (replace the entity_id by yours measuring the power and the level of power you want your automation to be triggered when the power is coming from above 10 to below 10 in my example):

    - platform: numeric_state
      entity_id: sensor.your_sensor
      below: 10
3

Hi Browetd, this is exactly what I have. The problem is that when the machine is off, the numeric state below 10 will trigger a new automation. This is the reason why I would need a falling edge detection instead of a level below 10 detection.

4

So what you want to do is to trigger the automation when the power is 0 (?) but only if the power was around 1000 W a few seconds/minutes ago… Correct ?
What is the power consumed by this equipment when idle ?

5

You could use a trend sensor or a derivative sensor:

6

It is actually when the power goes to 0, from wherever it was. I just gave 1000W as this is the power in normal operation. Sometimes the power goes to 100W, when the drum is just circulating for example.
Means, I need to trigger my automation when an edge to 0 is detected.
The power consumption in idle is very low. I just see 0 Amps. Means even the current times voltage (Power in W) is 0.

7

So I do not understand why the automation will trigger when the machine is off… It will only trigger if the power is going down below 10… Pre-requisit: the power was above 10 before switching off ?

8

The dryer gets in warning of fault from time to time. It seems to be an issue from the factory, firmware related. We had a technician at home who checked the machine and it is all right. He replaced the pump and filters, but the problem continues. So, I planned to do a workaround to let the machine cool down for some minutes and re-start it with a finger-robot. For this I need to detect a falling edge, which will evaluate if the machine is under fault or if it has finished the cycle.

I found workarounds to detect each state of the machine (cycle finished, failure and manual start), but now I just need to find a way to trigger the automation on falling edge (from whatever value to 0).

9

I like your idea with the derivative calculation. I will test it.