Re: "Colorimeter"

On 24/05/2025 21:07, Don Y wrote:

On 5/19/2025 1:33 PM, Lasse Langwadt wrote:

On 5/18/25 21:45, Don Y wrote:

On 5/18/2025 6:13 AM, Lasse Langwadt wrote:

On 5/17/25 23:03, Martin Brown wrote:

>
If you are serious about doing this right then a 2D CCD sensor and a prism hires grating combo at right angles will allow you to quantify the entire visible spectrum at ultra high resolution.

>
use a CD https://youtu.be/EoAZ-u6hn6g?si=Mv-DfJ5swtq2-j1X&t=98  :)
>
eons ago we used some CCDs as detectors for X-ray fluorescence, some had weird formats like 1024x64 pixels so I assume they were really made for spectroscopy

>
As mentioned elsewhere, how do they fare when light is shining directly on the
sensor?  How do you keep it from saturating -- dark lens to attenuate the signal?

>
or a shutter to limit the time light hits the sensor

 There's still a limit as to the peak intensity that a sensor can
tolerate.  And, gating the light (instead of attenuating it)
means there is no signal when the source is gated off.

Simplest solution is to limit the aperture that you let the light in through which is normally focussed onto a narrow slit anyway. You might get a bit of an issue with readout smearing but it probably won't be too bad.
Please bear in mind that my experience with spectroscopy the problem was mostly getting enough light to have *any* signal to noise.

 Fine if you are making a device with a button that says "measure now".
But, if you expect to be able to collect data at any time, you
want to be sure data is available.

In extremis the measure now button could just move a spring loaded mechanical shutter that normally blocks the light path.
Unless the thing is imaging a nuclear blast, steel furnace or an arc lamp then I don't think light intensity is likely to harm a modern CCD. There are hot mirror and anti-UV low pass filters to protect such equipment from hostile radiation.
--
Martin Brown