We have seen single color LED detection before, fjordcarver has built a DIY Color Detection using an RGB LED that can detect the actual color of the object placed in front of the home made sensor.
“For this sensor you will need
- a breadboard (not required, but it is how I will walk you through it.)
- an RGB LED (alternatively you could use 3 LEDs)
- A 220 ohm resistor
- A CdS photocell (these can be salvaged out of all kinds of things like nightlights or garden lamps)
- An Arduino, or a clone. I am using a RBB in this example”
