Mystery "Light 1"

I had a new device show up yesterday called “Light 1”. It was on since about 4pm and used a remarkably consistent 625w. In an attempt to identify what it was, I shut off every single breaker in my home; none of them turned off “Light 1”. I didn’t really expect it to I suppose since it was evening and nothing was running that wasn’t already identified. In fact, it didn’t go away until I restarted my Sense. Now it’s gone and hasn’t shown back up.

Any thoughts?

It can happen where Sense picks up the “ON” signature but misses the “OFF”. So Sense will think the device is still on when it’s not.

How were you monitoring whether Light 1 was on ? The bubble ? As @samwooly1 mentioned, Sense is looking for the signature of an off-event to make the bubble go away. If it misses an off-event, it will stay on until Sense times out on the bubble (maybe several hours later). And flipping the breaker off might not look the same as an off event for the light.

Best thing to do is to just leave the device alone for a few days or weeks of cycling so Sense refines its understanding of Light 1’s off event. The breaker test is only really effective if the 1) device is actually on, and 2) you are watching the Power Meter display for a corresponding 600W drop.

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I didn’t know that. I figured Sense was identifying the device’s running state in addition to the on/off events. If it’s as simple as missing the “off” event then I’ll just hold out and see if the detection improves.

Thank you!


Sense mainly “detects” and learns from short transitions, not levels and durations, because the transitions (especially the sub-second transitions) convey the most identity information at a fundamental physics level. I say mainly, because Sense has started to do some identification of big loads that can’t be identified by physics-based signatures, things like EV chargers.

I believe Sense captures a little bit of the operating power level of a device from the on and off signatures, then synthesizes it via prediction for the Device Power Meter waveform, rather than monitoring it continuously. For complex devices, with different cycles, Sense might detect the cycles independently, then fuse them together.

Lots of good info on how detection is done in the technology blogs:

I have a device (fridge defroster) that the off is always missed. I know that the defrost runs for 11-18 minutes but I have a notification set to warn my if it’s been on for 30 minutes.
I get this notification daily as Sense has not picked up the off signature in several months.

Although Sense doesn’t see the signature, the device power meter is usually correct. Just kind of strange.