Treatment & Detection of Multiple Identical Household Devices

I have two completely identical air purifiers in my home. Most of the time they are on (in different locations) at the same time. Each has three fan speeds (and I am assuming, power profiles).

How will these two devices get detected by Sense? Will they be detected as one device if both are on at the same time, which would mean if only one is turned on, will it know that it is a device on its own? Or will it only recognize it if both are turned on because of the power profile that the machine learning detected?

If it is able to detect a single instance of the device…what happens when Sense “sees” two identical products with the same energy profile? Will it detect that I have two devices turned on? Or will it perhaps detect that I have one device turned on at double the energy profile?

Honestly, I am not even sure if I am asking all the different combinations and permutations of the use-case where a Sense household has multiple identical devices with different power settings on each… Seems like a very complex thing to detect and represent…


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Three things to think about as you ponder this problem.

  1. Sense (mostly*) looks at roughly a half second transition when a device turns on or off for the on-signatures and off-signatures, for all sorts of parametric information (maybe 20 or so parameters of features) that can be extracted from that transition. If Sense finds a clear, unique clustering of those parameters in the feature space for a on-type transition and a matching unique off-type transition, then a device is detected. I said “mostly” earlier, because Sense also looks for a few slower than half second big ramps for EV chargers and mini-split AC units, etc.
  2. If two devices have exactly the same parameter/ feature ranges for their on and off signatures, including being on the same leg of house wiring, then they might not be recognized separately. Not sure how Sense handles what it might think is an on-on-off-off transition sequence caused by two identical devices. If your fan has an AC motor, it’s likely turning on, and off from each speed is going to give a different on and off signature. If it’s a DC motor, Sense may never see a detectable on or off signature (DC power supplies don’t have nice on and off signatures).
  3. You need to think about Sense detection in terms of on and off transitions - that’s how it detects the device and that’s what it uses to predict the power level the device uses. So if a device suddenly uses more power (garbage disposal suddenly grinds something bought), Sense won’t see an increase in power, because it’s only looking for on/off transitions.
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Ah… Wait… So the device/appliance detection has nothing to do with the usage pattern/dynamic once it is turned on… The detection is only done in terms of detecting its “on signature” and its “off signature”. Is that correct? Runtime behavior and signature is not a consideration?

Is that why my coffee maker (which comes on at a burst of about 1,200 Watts) is constantly identified as on, when it’s really my toaster oven, or my washing machine?

Interesting… Thanks for that detail…

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So yes and no…

Sense only looks at the transitions…

It still might have ways of sorting out patterns from identical devices…

Very interesting. Sense can’t differentiate my wife’s hair dryer from our microwave. Sounds like the problem you have also.