zForce AIR sensors detect and trace objects by detecting diffusely reflected infrared light.

Requirements on the object to detect include:

• A minimum reflectance (~>30%?) is needed for proper signal levels, that is, the object can not be too dark.
• Object surface must be diffuse. A glossy or mirror-like object may not scatter enough light towards correct receivers.
• Object must be large enough (~>5mm?) to ensure sufficient signal levels. This is closely related to reflectance. A white, diffuse object may be smaller than a dark, glossy one.