>a current product has an issue of activating in moonlight or with car headlights, any ideas ?

Sensitivity adjustment will take care of moonlight.

An activation/deactivation Time-Delay will take care of Car Headlamps.

A Time-Clock will take care of switching during Daylight Hours. Most places on the planet publish "Lighting-Up" Times.

A combination of all three should give you a better product.

Oh... and sensible positioning of the Sensor (like pointing skywards - and not towards where the moon normally traverses) always helps!