The answer is on the second page of this article.

Another Empeg question which that article answers better is "Why is the Empeg-Car the only product in the world to use a blue LED for Ethernet link?"

The pulsing LED on the front is actually a white LED, which is even cooler than a blue one.

Peter

I have to say, that's the one thing I miss now that I've got the home docking stations: No ethereal blue glow radiating from the back of the player.

Speaking of white LEDs, have those LED lights been created yet? I think Philips was making them, but I haven't heard anything about them in a long while.

Um, there's a white LED in the player and Brian uses white LEDs in his button kits. You can get them at radio shack. What exactly was your question?

I just know that Philips was trying to make houshold lights out of white LEDs. I'll try to find the article.

*edit*
found it

Ah, I see.

Seems to me that actual white LEDs aren't required for that application, a cluster of R/G/B LEDs would serve the same purpose. And if you did it that way, you could even adjust the tint to simulate either incandescent, flourescent, or outdoor light.

Nah, we all know the real answer to this question is that Hugo needed something to match the interior in his VW bug

If I'm right about what I've read on the empeg's beginnings... he didn't have a Bug back then...

A bit of a shame really - the stock lens isn't a very good match. If only he'd bought that bug earlier then I'd have a perfect match for my golf.

In reply to:

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I have to say, that's the one thing I miss now that I've got the home docking stations: No ethereal blue glow radiating from the back of the player.

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When I built my home docking station, I seriously considered (and still am considering), using a small plastic "light guide" to bring the blue LED to the rear of the docking station near where the Ethernet jack is from the back of the player.

This would not just be for practical reasons of verifiying that the ethernet link is active (as its original purpose was), but also for that nice blue glow at the back when its connected to the network.

Ahh - good thought. I've been getting the bits and pieces to gether for my home dock and I'll just add light guide to the list of outstanding parts

Cheers

AIUI, white LEDs are a cluster of different-coloured LEDs in a single package. So your idea of colour-temperature adjustment, or similar would work equally well on (suitably wired) white LEDs as discrete colours. And if you're a semiconductor manufacturer, you're probably in a position to produce white LEDs with per-colour controls.

It would certainly simplify assembly if all the component LEDs are identical.

I always do a double take when I see LED traffic lights - the instant light is noticeable compared with the several centiseconds incandescents take. I wouldn't have believed I'd ever notice the warm-up time of a traffic light bulb, but you can indeed tell the difference!

[Edit: changed "fraction of a second" to "several centiseconds" for clarity]

I always do a double take when I see LED traffic lights - the instant light is noticeable compared with the fraction of a second incandescents take. I wouldn't have believed I'd ever notice the warm-up time of a traffic light bulb, but you can indeed tell the difference!

Are there some in Cambridge then?

Peter

Don't know about Cambridge, but there are plenty of them around London. They really do change disconcertingly fast...

Haven't noticed any LED traffic lights in Cambridge.

The place I normally notice them is on the A650 through central Bradford (on my way to/from the Lake District or Yorkshire Dales), but I've seen them in other places too. If only I could remember where!

There are the natty LED cat's eyes up towards Madingley, but I think that they already got a mention here a while ago.

I have been noticing them on the back of truck trailers here in the states.

Seems to me that actual white LEDs aren't required for that application, a cluster of R/G/B LEDs would serve the same purpose. And if you did it that way, you could even adjust the tint to simulate either incandescent, flourescent, or outdoor light.

Would that actually work? I thought LEDs only emitted a very narrow frequency range. Even if you can get them to look "white" or "incandescent" when viewed directly (for people with normal colour response in their eyes) you're still going to get pretty weird looking colours when you use it to light a room. Don't most real objects have continuous absorption spectra?

I'd be interested to know how the Phillips gang were planning to overcome this.

Richard

Would that actually work? I thought LEDs only emitted a very narrow frequency range.

Very interesting point. A spectrogram of an RGB LED cluster would look like three peaks, but a spectrogram of an incandescent would be a wash of color with mild variation.

I hadn't thought of that.