EverBright Bulb

DC continuity, line capacitance, or residual hum detection, perhaps.

Cheers

Phil Hobbs

Rise time (spark detection, but also TRIACs and such) would be another possibility.

Tim

I doubt it's as simple as this...

------------|>|--- | R | ---R----+ | | --- ----- LED

Hum detection via a capacitor would probably be the most idiot-resistant. 120V 60 Hz through a 1-pF open switch contact would be about 40 nA, not hard to detect.

Cheers

Phil Hobbs

Are you asking about this one?

It says it will go on if you hold it in your hand. Someone should do a tear down video.

George H.

Okay, ambient hum then.

Cheers

Phil Hobbs

no

no

no

Well, what then?

How does it work?

So it must be able to detect absence of 50/60 Hz emi field in some way ?

US8907523B2 is a rather lengthy description of what's going on. My guess is a uproc based digital lockin impedance analyzer that "polls" the state of the switch. The bulb will not light on power failure if the switch is in OF F position for example. Patent is assigned to TLV who sued Sengled (Everbri ght) for infringement but lost.

Example of substituting smarts (software) for brawn (hardware), resulting in very economical implementation.

is a uproc based digital lockin impedance analyzer that "polls" the state o f the switch. The bulb will not light on power failure if the switch is in OFF position for example. Patent is assigned to TLV who sued Sengled (Everb right) for infringement but lost.

US8907523B2 Ughh, can anyone read such stuff? So it measures the switch state by seeing there is continuity back through the transformer? (just a guess I didn't read the patent.)

George H.

e:

s is a uproc based digital lockin impedance analyzer that "polls" the state of the switch. The bulb will not light on power failure if the switch is i n OFF position for example. Patent is assigned to TLV who sued Sengled (Eve rbright) for infringement but lost.

They claim the circuit does not require "augmentation" and other loads can be on the same circuit as the bulb, which tells me it's adaptive in some wa y, it learns the impedance measurement of the two switch ON/OFF positions.

This one is rated better:

Reading the reviews shows the bulb can be the only item in the powered circuit, if it sis in parallel with anything else it won't perform as expected. Single bulb in the middle of the room? Works, one of several bulbs on the same switch, just works as a normal bulb, does not detect power outage.

Interesting use of electrical theory.

John :-#)#

ote:

ess is a uproc based digital lockin impedance analyzer that "polls" the sta te of the switch. The bulb will not light on power failure if the switch is in OFF position for example. Patent is assigned to TLV who sued Sengled (E verbright) for infringement but lost.

n be on the same circuit as the bulb, which tells me it's adaptive in some way, it learns the impedance measurement of the two switch ON/OFF positions .

OK, I guess it doesn't have to 'see' all the way back to the (pole) transformer, there will be other loads turned on inside the house. But then it also detects your hand ~1k to 100k ohm of impedance... I guess a phase sensitive measurement could ignore capacitive impedances.

What does augmentation mean?

George h.

I think when the power is off it looks at the impedance across the base. I saw a video of the guy using his fingers across the base of a bulb in his hand to turn it on.

So if the switch is off it, sees hi Z so stays off. If the switch is on it sees power and uses it or it sees the unpowered grid which is a low Z so it comes on with the battery.

If it is in parallel with another bulb it will come on whenever the switch is off, so that won't work.

What they don't tell you is how long will it stay on in a power failure. The built in battery cannot be very large.

It is clever idea though.

mark