Or you can go back to basics and build this reflective RGB sensor from an LED and a photocell ... lights on an object and measure how much light it reflects. If you know the red, green, and ...

Matt black outdoor wall light Solar powered Dimmable Photocell & PIR sensor 110˚ detection angle - 8m maximum range 25 second timer function Constructed from stainless steel & polycarbonate Supplied ...