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From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: sci.electronics.design
Subject: Re: "Colorimeter"
Date: Sat, 24 May 2025 05:26:57 -0700
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On 5/22/2025 11:45 AM, Martin Brown wrote:
> On 22/05/2025 18:34, Don Y wrote:

>> I.e., almost like a photographer's "light meter" but with the interest
>> being on the spectral content and not the overall intensity.
>>
>> [Whether this is true or not, it has influenced how *I* have thought
>> about the problem -- in terms of function, size, portability, power
>> requirements, etc.  Assumptions are always the bane of a good design... :< ]
> If the light levels are very high then you can get LEDs with emission profiles 
> of about 50nm width. They work as sensors in the opposite direction with some 
> leakage for higher energy photons. Choose them wisely and calibrate against a 
> reference white and you might have something that is both cheap accurate and 
> durable.

My original approach was along similar lines.  But, resulted in a large-ish
sensor (many LEDs).  I had toyed with a similar "sun detector" concept
(LEDs focused in different directions along a hemisphere) many months back.

Again, without specifics, I didn't know how much leeway I could propose in
a solution.  So, went looking for smaller, more "integrated", that they
could have more flexibility in adapting, packaging, etc.

[I'm not keen on spending a lot of time on this as it's just a "favor"
for an old client (who treated me quite we$$).  Hopefully, they can sort
out specifics that are more appropriate to their design constraints.  I
also want to avoid the possibility of getting "sucked into" a design;
I've got far too much on my plate, already, than to have to deal with
a client!  :<  ]