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On Mon, 01 Dec 2008 21:28:51 +0000, Orchid XP v8 <voi### [at] dev null> wrote:
>> Solar panels. Infrared remote control receivers (i.e., photodiodes).
>> Optical sensors on doors.
>
>Infrared receivers *respond to* light. They do not actually *transform*
>it into electricity.
They respond to light (IR) by the light energising the base of a transistor the
same way an electric current does. In fact you can make a photo transistor by
opening the can of a metal clad tyranny.
--
Regards
Stephen
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Fredrik Eriksson wrote:
> On Mon, 01 Dec 2008 12:11:43 +0100, Invisible <voi### [at] devnull> wrote:
> I used to have a solar powered pocket calculator. Worked pretty well
> indoors too.
Many such gadgets do include a battery. My solar powered calculator
would work well in complete darkness. Until the battery ran out (took
about a decade to do so!). Now it works, but needs some light (not much,
though).
--
Intaxication: Euphoria at getting a tax refund, which lasts until you
realize it was your money to start with.
/\ /\ /\ /
/ \/ \ u e e n / \/ a w a z
>>>>>>mue### [at] nawazorg<<<<<<
anl
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On Tue, 02 Dec 2008 01:02:37 +0100, Mueen Nawaz <m.n### [at] ieeeorg> wrote:
> Fredrik Eriksson wrote:
>> On Mon, 01 Dec 2008 12:11:43 +0100, Invisible <voi### [at] devnull> wrote:
>> I used to have a solar powered pocket calculator. Worked pretty well
>> indoors too.
>
> Many such gadgets do include a battery. My solar powered calculator
> would work well in complete darkness. Until the battery ran out (took
> about a decade to do so!). Now it works, but needs some light (not much,
> though).
Not this one. If you held your hand over the solar cells the display would
blank out right away. I still have a non-solar-powered calculator though
that runs on its original battery even after twenty or so years. The power
consumption of such devices is astonishingly low.
--
FE
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"Fredrik Eriksson" <fe79}--at--{yahoo}--dot--{com> wrote:
> Not this one. If you held your hand over the solar cells the display would
> blank out right away. I still have a non-solar-powered calculator though
> that runs on its original battery even after twenty or so years. The power
> consumption of such devices is astonishingly low.
I remembered if I covered the solar cells for the right brief amount of
time, the number changed in such a way that I think only some bits got
cleared :)
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> Which leads to another question: Do surface hilights really exist? Or are
> they just reflections of the shape of the light source?
They do exist, and they are not just reflections of the shape of the light
source. They are due to the geometric structure of the surface on a very
small scale. Think about each surface IRL actually having something like a
normal{bumps scale 0.000001} block and then rendered with perfect
anti-aliasing... even a point light source will give you a non-zero sized
highlight.
Diffuse, specular and reflection are all the same thing IRL, it just depends
on the geometry of the surface. IIRC some light reflection model used in 3D
cards (or maybe POV too) is based on theoretical analysis of random surface
variations. Something like assuming the surface to be made up of a
triangle-wave with each peak a random height. You can calculate the % of
light reflected in certain directions mathematically and with a few
simplifications come up with a model for diffuse and specular components.
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Darren New wrote:
>
> Solar panels. Infrared remote control receivers (i.e., photodiodes).
> Optical sensors on doors.
>
Don't forget digital camera sensors. DRAM chips, too.
--
~Mike
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Invisible wrote:
>>> It's more that, in everyday life, there is no way of turning light
>>> into either electricity
>>
>> Solar panels.
>
> And when do you *ever* see those in everyday life? ;-)
You have probably seen several solar powered calculators, watches and
torches.
See:
http://www.amazon.com/Casio-FX-260-Solar-Scientific-Calculator/dp/B00004TVDT
http://www.globalsources.com/manufacturers/Solar-Torch.html
http://www.thesolarcentre.co.uk/catalog/Solar_Watches-27-1.html
http://www.thesolarcentre.co.uk/
--
Tor Olav
http://subcube.com
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scott wrote:
...
> For example, you know how light "bends" when it enters eg glass, well
> how much it bends is related to the refractive index of the material.
> And if you know the "electrical" properties you can calculate this
> refractive index exactly (it's the square root of permittivity times
> permeablility of the material).
...
Heh - now you just reminded my of this Google calculator expression:
http://www.google.no/search?q=speed+of+light+times+square+root+of+%28permittivity+of+free+space+times+permeability+of+free+space%29
http://tinyurl.com/5etcgr
--
Tor Olav
http://subcube.com
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Tor Olav Kristensen wrote:
> Heh - now you just reminded my of this Google calculator expression:
>
>
http://www.google.no/search?q=speed+of+light+times+square+root+of+%28permittivity+of+free+space+times+permeability+of+free+space%29
> http://tinyurl.com/5etcgr
>
http://www.google.com/search?q=once+in+a+blue+moon
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Nicolas Alvarez wrote:
...
> http://www.google.com/search?q=once+in+a+blue+moon
=)
So we have a blue moon about every 33rd month ?
http://www.google.com/search?q=one+divided+by+once+in+a+blue+moon+in+months
--
Tor Olav
http://subcube.com
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