Optical highway line detector

摘要

A highway lane position detector including a photodetector for determining the existence of highway lines, wherein the detection circuitry maintains its detection ability over a wide range of ambient light conditions from bright sunlight to dim artificial light in ambient darkness, by providing a dynamic resistance element in series with the photodetector wherein the dynamic resistance element compensates for changes in the photodetector due to changes in ambient light conditions to maintain the photodetector in a detection condition (avoiding saturation) regardless of the ambient light condition. In the preferred embodiment of the detector, the dynamic resistance element is at least one reversed biased zener diode. In currently preferred circuitry of the invention, the detector detects the presence of intermittent lane dividing lines and provides an alarm when such lines are no longer detected.