The color reader... again!

Yes. It is only good for a qualitative test, but aluminised shovelware CDs are great for demonstrating the Fraunhofer lines in the solar spectrum at glancing incidence. Cheap and virtually indestructible - they don't play very well after being used as frisbees in a classroom.

Usual safety warnings about not looking directly at the sun apply.

It is amazing just how impure some older yellow and green LEDs are.

BTW can anyone recommend a high brightness yellow LED ideally centred on

585nm with about 10nm FWHM spread. Could live with peak brightness anywhere between 580nm and 590nm but I want it to match a filter.

There was a Cree one that on paper meets my spec but it is only available in the UK to special order.

Regards, Martin Brown

Here's a handheld spectroscope that I have ($8.95), If I get time...I'll hook up a couple of leds and see is I can resolve a difference.

Mikek

Well, I'll be! You've actually come up with a realisti use for yogurt! ;-)

(I've dropped the 'h' - my spell checker doesn't like it.)

Cheers! Rich

hehe I've done that on a couple of boards designed to be customer-visible. It does look nice, black+gold. But the assemblers complained because it was apparently too black for the sensor that detected the edge of the board on the conveyer :)

Another drawback is you can hardly see the tracks if you are debugging.

--

John Devereux

The matte black mask is a necessity for companies who make LED traffic lights. BTDT.

I actually like it. But now we still have to come up with a realistic use for tofu. That stuff taste like nothing, like wet cardboard.

--
Regards, Joerg

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I can provide detailed plans, if desired, to use either DVD (one angle) or CD (another angle) in a cheap box you make with thick, crepe paper with foldable tabs glued with elmers to make the box. Tiny slit is cut (you can use razor blades to make an adjustable and precise slit, if desired) in the box and there is a nice opening where you can either use your eye or else a cheap camera. Pixel calibration, if you go the cheap camera route, for wavelength is done with an $8 merc-argon lamp and a little software I can also provide. Whole thing is close to free to make. If DVD is used, don't use DVD-R or DVD+R -- they have a nasty dead band in the red. Use DVD-RW.

Anyway, can easily separate yellow doublets less than 2nm apart, for example.

Intensity calibration is another, more difficult story. But might not need that to start out.

Jon

I never liked those, either. Air-powered suckers work like a champ, though. Either that or Solder Wik. Forget the silly bulbs and plungers.

Tofu makes a good imitation mushroom.

What? Are you trying to put Charlie out of business? ;-)

Thanks! I'm ordering one, just to have around.

But it won't make it taste different than wet cardboard. Yuck. There's always some in the miso soup at our Japanese place and I eat it, but only because I was brought up not to let anything on the plate go to waste.

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Regards, Joerg

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Sure, but isn't that the point of tofu (or mushrooms)?

My parents tried that crap on me too. "So send the &$^% Brussel sprouts to the starving Chinese, already!".

Don't know about tofu. But mushrooms can be rather tasty.

I love Brussels sprouts. But I am not a fan of those nearly-vegetarian all cabbage dinners. I'm a meat and potatoes guy.

--
Regards, Joerg

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Same here. Some kind of beef every day keeps the B-vitamin levels up, and potatoes are a good source of vitamin C ;-) ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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I love to cook with wine.     Sometimes I even put it in the food.

Yes, they taste like tofu; wet cardboard (with an even worse texture).

Umm, Brussels sprouts are *not* meat and potatoes. ;-)

Ya, it's cool, you'll run around the house looking at all the lights a couple times and then it will set on a shelf until someone mentions spectroscopes, then you'll pull it out again just for kicks. :-) Mikek

Tofu is like cauliflower - only useful for soaking up a good sauce.

Pretty good in miso soup, better in marbudofu (Chinese version of chilli-con-carne) and best as kitsune udon noodles (literally fox - actually it is deep fried to the colour of a fox's coat). YMMV

Inauthentic recipes but gives some ideas.

Regards, Martin Brown

Try the shovelware CD at glancing incidence too. Best instructions these days on Maurice Gavins page at top right corner:

It is ideal as an easy incredibly cheap science demo to show people how "white" light is not all that it seems to be. eg CFL vs incandescent

Regards, Martin Brown

;-)

Then you must have never tasted the good ones, like these:

Right after I met a girlfriend who is now my wife we had a stop-over at an airport and headed for the duty-free shops. She bought a package with a miniscule amount of dried mushrooms for a whopping $20 or so. I thought "Whoa, that woman is a spender, she'd going to be high maintenance!". Until she cooked a wonderful meal with them ...

Well, I eat them as side vegetables, next to whar the taters are ;-)

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