I recently purchased some ZigBee Sengled Smart Light Bulbs. I have one switched light socket in my basement and several pull chain light sockets. I wanted to see if Rule Machine could sense the state of the switched bulb and have the bulbs in the pull chain sockets follow the state of the bulb connected to the switch. I was successful, but I am confused how one part of this works. When I turn off the switch and thus remove power from the ZigBee bulb, somehow the ZigBee bulb is able to send a ZigBee message saying it was turned off even though power was shut off to the bulb. Here is the log message sent from the bulb after power was removed:
[dev:165] 2021-01-27 08:25:42.343 pm [info] basement switched bulb was turned off
Where does the bulb get the power to send the ZigBee message after power is cut to the bulb? Does the bulb store some charge specifically so it can send a message when the power is turned off?
I don't think anyone knows for sure, but community experience matches the behavior you described, and I think the guess you made is a reasonable one: when the bulb detects power loss, it likely uses whatever residual power is left to send an "off" report to the hub, giving the hub a hope of keeping the state in sync even when power is cut. Most bulbs don't do this, which, of course, is pretty reasonable due to the fact that they did lose power, so Sengleds are special in this regard.
(Also, most people will tell you not to cut power to smart bulbs; there are a variety of methods like button devices or automations you could use to avoid physical power cuts while still maintaining something resembling normal control of the bulb. But since Sengleds don't participate as "repeaters"/routers in your mesh, the downside in this case is minimal except for the obvious loss of smart control while they're in this state. Mentioning this anyway since I'm sure someone would have otherwise...)
Is there any way to tell if the bulb was turned off via HE or power was cut? Just before I saw this, I discovered that the cleaning crew had turned off a switch that controls a lamp with a Sengled bulb. Was wondering if I could set up a notification if someone cut power to these bulbs.
These bulbs will send a notification if they turn off, either because power was cut or if they were turned off from a ZigBee command. You could have Rule Machine trigger on a change of state. I don't know if it would be possible to poll the bulb in response to this change of state and take an action of the bulb does not respond.
Enthused by learning the Sengled bulbs very helpfully send a ‘power off’ when turned off at the switch I bought some... only to find they don’t send a ‘power on’ when they are switched back on
How perverse why would Sengled not implement this .. there must be a good reason?
My "switched" bulb sends an "on" command when it is switched on as well. My Hubitat turns on the other lights when the switched bulb sends a message that it was turned on and turns off the other lights when the switch bulb sends a message that it was turned off.
dev:1652021-02-07 10:22:39.032 am basement switched bulb was turned on
