# How to recognize doorbell sound

**URL:** <https://discourse.nodered.org/t/how-to-recognize-doorbell-sound/29360>\
**Category:** General\
**Created:** [2 July 2020 08:49 UTC](https://discourse.nodered.org/t/how-to-recognize-doorbell-sound/29360 "2020-07-02T08:49:22Z")\
**Posts on this page:** 1\
**Showing post:** 13

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**Author:** ![janvda](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/janvda/32/234_2.png) [@janvda](https://discourse.nodered.org/u/janvda)\
**Post date:** [5 July 2020 08:59 UTC](https://discourse.nodered.org/t/how-to-recognize-doorbell-sound/29360/13 "2020-07-05T08:59:35Z")

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> [@ghayne](#):
>
> You could put an accelerometer near the bell to detect vibration.

Thanks, original idea.  
Not sure if I put an accelerometer near the bell that it would be sensitive enough.  
Of course this solution also needs power (or batery power).

> [@dceejay](#):
>
> or a magnetic switch on an esp in deep sleep mode to save battery power, and put the magnet on the clapper.

another original idea :-).  
Seeing how the bell rings, I am not sure if a magnet sticked to the clapper will last long.  
It will also require precise positioning to assure that reed switch swiches.

... but maybe I don't need an extra magnet as the clapper itself is triggered by a magnetic field.

> [@TotallyInformation](#):
>
> so you could easily detect voltage or current when the bell-push is triggered.

... that was an option I was initially thinking of. To measure the current in the low voltage circuit.  
But this also requires a powered ESP device.

> [@TotallyInformation](#):
>
> ...and quite possibly the bell ringer would have sufficient capacity to run the sender.

... very polite people seem to press very shortly on the bell. Not sure if this would last long enough to wakeup a deep sleep device and get it send a message. I understand that 433 MHz would require less energy than Wifi. But 433 MHz would add another component to the solution (ESP comes with wifi out of the box).

> [@dceejay](#):
>
> (or indeed you could probably parasite power from the bell itself.)

Note also that the low voltage circuit is AC (around 8V) and that when the bell is ringing that this circuits is interrupted with high frequency. So it is not that easy to use that power and also not clear that it would provide sufficient power during that short period.

... I also like the youtube video about the smart switch hardly requiring any power. But this would mean that I need to hack my doorbell button so the doorbell button is switching both my existing bell as well as this smart switch.

> [@cymplecy](#):
>
> I think you're all missing that @janvda doesn't want to connect anything to it 🙂

That is very true. I am indeed looking for a pure software solution.  
... but all hardware alternatives posted here are also well appreciated.

> [@ghayne](#):
>
> Ah, a quantum tunnel!

🙂 I think you look too far. I was thinking about the sound waves my doorbell makes.

> [@JGKK](#):
>
> you could probably take a wake word listener like [precise](https://github.com/MycroftAI/mycroft-precise)

... very very interesting. I will give _precise_ a more precise look.

> [@JGKK](#):
>
> Not sure how good the success rate would be as training wake word models and trimming data sets for them to get the best results is kind of like a witchcraft and involves a lot of trial and error but it should be possible.

... I am just wondering if any training could be limited as my doorbell is making a very specific ring sound. I would somehow expect that it is possible to define a "specific filter" for that sound based on the recording of a single ring where there are no background noises.

> [@E1cid](#):
>
> it looks like it would work with a 12v dc transformer.

No, it is an AC transformer (I think to 8V) in my case. So I guess this means that using Shelly 1 connect is not an option for me.

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