Need some ideas from the brain trust on an automation

Configuration
1

So,

Both my wife and I are getting a bit forgetful. We’re both late 60’s, so stuff happens.

We moved into a new house about 18 months ago which has a Thermador range top stove that has no visual indication that a fire is lit.

The knobs are configured so low fire looks a lot like off.

Both of us have let a fire on for fast longer than necessary in the past.

I’ve got two Sonoff temp/humidity sensors. One is under the vent hood and one is on top of the vent hood.

What I’d like to do is compare the two and if the temperature exceeds a set difference for longer than some period of time then send me a notification.

I did a quick lookie see, and nothing jumped out at me as a straightforward way of setting this up.

Any ideas would be greatly appreciated.

Cheers,

Chris

2

This should help you get started.

alias: example
triggers:
  - trigger: template
    value_template: >
      {{ states('sensor.bottom') | float(0) - states('sensor.top') | float(0) > 20 }}
    for:
      minutes: 5
conditions: []
actions:
  - action: notify.whatever
    data:
      title: 'WARNING Overheating detected'
      message: 'Check stove. It may have been left on.'

Reference

Template Trigger

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3

Wow.

That’s beautiful.

Thank you

1 Like
4

I think you are going to need to include some sort of motion or presence detection, otherwise it’s likely the automation will just trigger while you are cooking and not serve it’s purpose.

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5

Have you determined what are the reported temperatures when a burner is on low but there’s no pot on it?

My guess is it might be challenging to distinguish it from a burner on high but with a pot on it.

6

It’s not your age or your memory. This happened to me too around a year ago - woke up one morning to realise I had left a pan on the burner on the lowest setting all night. It was by sheer luck that the oil in the pan polymerised instead of catching on fire, otherwise I might not be here to write this.

I did look into a couple of options on how I would prevent this ever happening again. There was this product which was advertised at CES a while back. While it looks good, it’s expensive and there doesn’t seem a clear way to get it into HA.
Alternatively, there’s pyroelectric sensors you can get (like this or this) which might be able to be integrated via ESPHome if only there was more info provided.

However, I’m not convinced these flame detectors will actually work properly until it’s too late. Even if they detected the tiniest of flames, if you have a pan on the fire obstructing their vision, they would only register once the pan itself catches fire. You might as well just use a smoke alarm at that point.

Ultimately, the ideal way to do it would be a smart gas flow sensor (if one existed) coupled with a valve closer (which luckily already exists). You’d then be able to hook up an automation which basically says:
IF lights are off/I’m in bed/it’s past 11
AND gas flow detected
THEN Alert me & close off gas valve.

7

I did some experimentation last night to see what the temperature differences were between the top and the bottom sensors.

With just one burner on, at the lowest setting, there was a 20 degree F difference between the top and bottom sensors.

The trouble is the refresh rate on these sensors is very slow. It took several minutes for it to update.

I think that’s sufficient for now.

Yes, I realize that while I’m cooking it’s going to send notifications. I can live with that, at least until it gets to be enough of an annoyance for me to look at other ways of doing this.

Appreciate all the advice. Will let you know once the automation is done how it works out.

Cheers,

2 Likes
8

Wow! I took a guess when I used 20 in the example.

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9

You are the wise one …

:smile:

1 Like
10

Sigh,

The upper Sonoff disconnected some 8 hours ago…

I’ll have to get different sensors.

cheers

11

I have installed magnets in my cooktop knobs and have installed reed switches for each one, grouped as front and rear burners not individual, I connected them to a Zen16 and use it to activate the extractor fan and also a burner left on warning.

1 Like
12

In our previous house, we had a Dacor range and there were indicator lights on the stove for each burner. This was a great feature, and would easily lend itself towards integrating into HASS.

This range top, a Thermador, has no such indication. If the sensor(s) can’t achieve the desired results, I’ll look at pulling the thing apart and putting in some sort of sensing, magnets, switches, etc.

Prolly won’t be doing this while it’s under warranty, thus the idea with the sensors.

cheers,

13

So, I got the automation setup:

alias: Kitchen.Send_Notification_When_Stove_is_On.Automation
description: Alert
triggers:
  - trigger: template
    value_template: >
      {{ states('Kitchen.eWeLink.Under_Hood') | float(0) -
      states('Kitchen.eWeLink.Over_Hood') | float(0) > 20 }}
    for:
      minutes: 30
conditions: []
actions:
  - action: notify.e_mail
    metadata: {}
    data:
      message: The stove has been on for over 30 minutes!
      title: Alert
mode: single

Tested it out yesterday. Works fine. Trouble is, the top sensor keeps losing connectivity. I’m guessing it’s faulty.

So, thank you @123 Taras, it’s greatly appreciated.

1 Like
14

You’re welcome!

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