(3/4/21) | Guess the device waveform, win a KASA HS-300 smart strip

Whole house fan or central AC fan.

A clothes dryer

A whole-house vacuum cleaner?
A house-battery backup system / battery?
A water-conditioning system/pump?
A house alarm panel going off?

Haha @Edison517, I admire your dedication here. I had to add a rule limiting the number of guesses so people don’t just go item-by-item through their device list :slight_smile:

Several of you have also mentioned the fact that this is on at 3:46AM. I would recommend looking past that, as the time it turns on is irrelevant in this case.

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So it isn’t user triggered? :grinning:

It is definitely user triggered (unless I’m unaware of some automation capabilities that exist). What i meant is it’s not something that runs automatically/intermittently throughout the evening.

fair enough, I’m curious what it ends up being!

A breaker/hammer drill?

Possibly some type of wave maker device for a very large aquarium or a specialty pool?
Seems like way to much consumption and speed for some type or rocking device.

I was thinking a solar tracker/rotator until you said it’s user triggered, not automated or run intermittently.

This is a device someone would typically have in their home? Meaning the average person could/would purchase one and use it in their home?

I do not have one, and I would venture to say most people do not have one. It would be more commonly found in a workshop or garage.

Someone’s guess came pretty close already - they were off slightly.

Air compressor?


We have a winner! @matthew_lasorsa - reach out via private message with your shipping information, your brand new HS300 will ship out next week.

Thanks to everyone that submitted a guess! We’ll do more of these, and I’ll make sure to only provide 3 hints in the original post. I feel like my comments narrowed this down a bit too much :slight_smile: .


Dang it. I thought of that, but your hint threw me for a loop as air compressors turn on and turn off automatically as needed to fill the tank.

My fault. Me being an apartment renter is becoming increasingly obvious.
I can send you over a KP-115 smart plug for my negligence :slight_smile: .
Send your shipping address over to me in a private message.

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Awesome! I think a few helpful clues were:

  1. Waveform only on CH 1 ==> 120V
  2. Average power of ~1500W ==> ~12.5 A
  3. Runtime of ~1 min, 5 seconds
  4. Both the average power and the amplitude of the pulses increase throughout the cycle, which may suggest an increasing load (i.e. the pressure in the air tank is increasing)
  5. The smoothness and consistency of the waveform seemed to rule-out any tool being controlled directly by a user. I was leaning towards an orbital sander, but figured a hand sanders waveform would have more randomness to it from the load varying as the user applied inconsistent amounts of pressure against the work surface.

@JustinAtSense, are you able to share details on make and model? I’m still curious why the waveform has this pulsed nature to it. I’m guessing the compressor’s design may be using some form of digital inverter or other modulating scheme.


At this time, all we know is that it’s an air compressor. I’ll touch base with Data Science tomorrow to see if they were able to find anything else out here.

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lol, when they are functioning properly they don’t run automaticity per se, only when triggered by a loss of PSI. They do shut off automatically when maximum pressure is reached as to not blow itself up.

They often leak at the quick connectors causing them to start up to build pressure which mine (in my shed) did at all hr’s including 3am for some time until I investigated why my lights flickered (due to the motor surge) and eventually repaired the connector preventing it from loosing pressure and automatically turning itself on.

The reason I thought some type of compressor is due to the ever so slight but consistent increase in consumption I thought I had noticed but didn’t make too much of as it looked to pretty. The reason for that is as the pressure increases the motor has to work slightly harder to build additional pressure. The pulsing is due to the compressor itself being like a small engine or sorts with compression cycles/stokes.
The smoothness of it had me really confused, almost thinking it was some sort of medical or other highly regulated device. Hence why I asked if it’s something a person would typically have in their home.

I did think of one of those small portable tire, ball, pool toy inflators but they only use about 1-200w.

No need to send anything as you weren’t really wrong more of a trick on words as you are correct in the aspect of it normally being user triggered, they aren’t supposed to randomly turn on and off throughout the day but they can.
Now you have me wanting to turn mine on an off a few times to see it in Sense.

I appreciate your breakdown here, thanks to this community i can begin to prepare to be a homeowner.

Let me know if Sense detects your air compressor and what the original device was named once detected (“device 1”, etc). I can see if i can get you a high-resolution waveform image of your compressor (with your permission of course) like I shared in the original post. It would be cool to see some difference based on model or type.

Is there a way to organize the Community Device Library by waveform shape? I know that this library has recently been updated to categorize devices by wattage ranges.

What got me thinking about this was a recent post, Unidentified spikes when pump is running. A user requested help identifying his mystery device and shared a waveform. He ended up identifying the device all by himself since none of us knew. I wonder if a knowledge dump from Data Science and/or the community might have given us the resources to help in such situations.

Maybe the number of waveform shapes is just too high to categorize, or maybe our language doesn’t have words to categorize waveform shapes. Then again, we won’t know if we don’t try! There is an essay on the Sense website about electric vehicle waveforms. I don’t recall essays specifically about the about key waveform features of motor devices or heat devices, but they might be there. What other categories come to mind?