LED lightbulbs and X10 dimmer switches?

[Tom Horsley]

As an experiment, I ordered an LED bulb advertised on its web site
as "compatible" with dimmer switches. As I sort of expected, "compatible"
doesn't mean it actually changes luminosity - it just means it works .
In practice, it comes on at some point and goes off at some point, and
no dimming seems to be evident.

With the light bulb police gaining ground all over the world, someone
must have figured out that there will be a market for replacement
bulbs that still work with X10 dimmers.

Surely it would be possible to build a bulb that measures the duty
cycle of the input AC and controls the brightness of the LEDs
from it (possibly a bit more expensive than the already expensive
LED bulbs, but what the heck, the switches are more expensive too)?

Anyone know of any LED bulbs that actually work well with X10 dimmers?
Anyone monitoring this newsgroup for new product ideas? .

 

[Bob]

As an experiment, I ordered an LED bulb advertised on its web site
as "compatible" with dimmer switches. As I sort of expected, "compatible"
doesn't mean it actually changes luminosity - it just means it works .
In practice, it comes on at some point and goes off at some point, and
no dimming seems to be evident.

With the light bulb police gaining ground all over the world, someone
must have figured out that there will be a market for replacement
bulbs that still work with X10 dimmers.

Surely it would be possible to build a bulb that measures the duty
cycle of the input AC and controls the brightness of the LEDs
from it (possibly a bit more expensive than the already expensive
LED bulbs, but what the heck, the switches are more expensive too)?

Anyone know of any LED bulbs that actually work well with X10 dimmers?
Anyone monitoring this newsgroup for new product ideas? .

I'm surprised that LED bulbs act this way. They should respond to the change
in duty cycle.

I've had no luck with fluorescents either. They won't start. I suspect it's
because their load doesn't meet the 10mA thrystor hold current right at
startup (but I really don't know).

Bob

 

[Lord Garth]

I'm surprised that LED bulbs act this way. They should respond to the change
in duty cycle.

I've had no luck with fluorescents either. They won't start. I suspect it's
because their load doesn't meet the 10mA thrystor hold current right at
startup (but I really don't know).

I'm running X10 as well and I suggest that you easiest move is to include
a load that the X10 wants to see in parallel with the fluorescent lamp. I
do
this in two rooms using a small 7 watt incandescent bulb in each room.

The other solution is to replace the triac within the X10 switch with a
solid state relay though this eliminates dimming.

 

[Don Klipstein]

I'm surprised that LED bulbs act this way. They should respond to the change
in duty cycle.

Many LED "lightbulbs" only draw current over some smallish portion of
each half-cycle of AC, probably around and just ahead of the voltage peak.

Ones lacking filter/smoothing capacitors should do better but will still
differ from incandescents by having "bottom" being higher, light output at
"midpoint of dimming" being higher, and "visually effective midpoint of
dimming range" being lower and a little close to the bottom.
Ones with the filter/smoothing capacitors do worse in this area as well
as draw current spikes that make RMS current draw well above ratio of
watts to volts.

- Don Klipstein ([email protected])

 

[James Thompson]

As an experiment, I ordered an LED bulb advertised on its web site
as "compatible" with dimmer switches. As I sort of expected, "compatible"
doesn't mean it actually changes luminosity - it just means it works .
In practice, it comes on at some point and goes off at some point, and
no dimming seems to be evident.

With the light bulb police gaining ground all over the world, someone
must have figured out that there will be a market for replacement
bulbs that still work with X10 dimmers.

Surely it would be possible to build a bulb that measures the duty
cycle of the input AC and controls the brightness of the LEDs
from it (possibly a bit more expensive than the already expensive
LED bulbs, but what the heck, the switches are more expensive too)?

Anyone know of any LED bulbs that actually work well with X10 dimmers?
Anyone monitoring this newsgroup for new product ideas? .

The way I would design the led bulb replacement suitable for dimming, would
be have some of the led's in the array be voltage switched in steps. As in
as the line voltage is lowered, some of the led's switch off in the array.
I have not seen one made like that, but as a home project maybe? How bright
is the led lamp you have - how does it compare for you to the lamp you
replaced?

 

[Bob]

I'm running X10 as well and I suggest that you easiest move is to include
a load that the X10 wants to see in parallel with the fluorescent lamp. I
do
this in two rooms using a small 7 watt incandescent bulb in each room.

The other solution is to replace the triac within the X10 switch with a
solid state relay though this eliminates dimming.

It's good to hear that the parallel load (min hold current) technique works.
I was going to construct a male-to-female socket adapter with an integrated
power resistor, but your solution is much simpler and it would probably
satisfy U.L., too.

Bob

 

[Tom Horsley]

How bright
is the led lamp you have - how does it compare for you to the lamp you
replaced?

It didn't replace anything - it was just an experiment, but it isn't very
bright. The web page (in addition to talking about dimmer compatibility)
also talked about "reading light", but any standard Mom would give you
hell for trying to read in the light this thing produces .

On the other hand, there are LED bulbs that I'm sure are plenty bright,
like this one (which I wasn't willing to buy merely as an experiment):

http://www.ledlight.com/detail.aspx?ID=27