Hello,
There are 3 LED’s on board of the Triad. So How does it able to produce 18 wavelengths??
The spectrometer is reading wavelengths that are reflected from the material. There are 18 pre-defined wavelengths that the sensor is ‘looking’ for. If the material absorbs that wavelength, then that can tell you something about the material’s composition or other light properties.
Excuse my ignorance, but The Triad contains a 5700k white LED, a 405nm UV LED, and an 875nm IR LED. So don’t we need 18 different LEDs to produce 18 different wavelengths or does one LED could produce the various amounts of wavelengths?? Thank you.
Spectroscopy is an advanced physics subject and it is difficult to explain on the forums. I would suggest looking into online research where possible https://en.wikipedia.org/wiki/Spectroscopy.
For our boards it boils down to reflection, absorption, and emission. There are three LEDs that cover different sections of wavelength. And the sensors observe specific wavelengths around those sections. The sensors data can be collected for material profiles and other material sciences.
White light sources emit multiple colors of light which combine into what we call white. White LEDs use one of two techniques. They either have red, blue & green emitters or the start as blue and use sophisticated phosphor compounds that absorb blue light and emit other colors. Either way, multiple wavelengths are generated. The wikipedia page on this is decent. Note the graph of a phosphor LED spectrum isn’t nearly as spiky as the three emitter graph: