Reflection illumination White LED part instructions requires more detail
I have built various iterations of the reflection illumination module and case over the past weeks. The biggest challenge I encountered was to improve the image quality, especially reducing vignetting. The most important issues I've encountered were with the LED. Most notably:
- The clear lens that comes with most LEDs causes non-uniform illumination of the sample.
- The required luminous intensity matters a lot.
Regarding 1: A diffuse lens LED with a high enough luminous intensity is hard to find. I ended up making the clear lens diffuse with sandpaper, which worked surprisingly well.
Regarding 2: The currently suggested LED (NSPL500DS) is rated 22 cd. In my experience, a stronger LED helps with the image quality. I ended up using the C503D-WAN-CCBEB151 (65 cd).
Adding this information to the documentation for the White LED part information (docs/parts/electronics/white_led) could save people some work in the future.
I'm currently finishing up a merge request to add this information to the docs. I hope you will be able to merge this. I'd be happy to make further improvements to this pull request where needed.