What is a LED Sun Photometer?

A Photometer is an instrument that measures the quantity of light radiation. A sun photometer thus measures the amount of sunlight through a detector that generates a measurable signal proportional to the intensity of sunlight. A Light Emitting Diode, or LED for short, is commonly found as indicator light in many consumer electronics, typically emitting green or red light.  LED is a semi-conductor device that emits light of a specific color (monochromatic) when a current passes through it. However, it also functions as a detector that is sensitive only to a specific color that is close to the color of the light it emits when used as an emitter. A LED Sun Photometer then is a device that uses LEDs sensitive to specific colors or wavelengths emitted by the sun, and the output is an electrical signal that is measured as a voltage with a volt meter (analog or digital).