Or you can go back to basics and build this reflective RGB sensor from an LED and a photocell. The principle behind [TechMartian]’s approach is simplicity itself: shine different colored lights ...

Don’t have a color sensor? You can roll your own with an RGB LED, a photocell, and not much else. If you’re wondering how they work, we’ve seen the color sensor demystified.

Light from an object makes its way to a sensor (see figure 1) in a camera. On the sensor there are millions of cells called photocells. Each photocell takes one bit of information about the entire ...