Re: "Colorimeter"

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!  :<  ]