Process and system for controlling a windshield wiper, particularly for a motor vehicle

A system for operating a windshield wiper, suitable for use on a motor vehicle, comprising:

• a sensor of intensity of rain on a windshield;
• a computer, and an analog/digital converter connecting said sensor to said computer;
• wherein said computer is operative in accordance with a program providing a process for controlling the windshield wiper, the process employing said sensor to give off a signal enabling the windshield wiper to be automatically controlled as a function of the intensity of the rain, and wherein a variation in the signal of the sensor is manifested as random signals produced by the presence of continuous movements of drops of water and serves as measure for intensity of the rain;
• and
• the process provides for observing, in a sequence of sudden changes in the sensor signal, a time elapsed between one of said sudden changes in the sensor signal and a later sudden change thereof exceeding a given value, and controlling the windshield wiper as a function of at least an earlier one of said sudden changes in the sensor signal which precedes said one sudden change during the elapsed time between the occurrence of the sudden changes.

A method of operating a rain sensor for actuating a device controlled by the sensor, wherein a change in a signal outputted by the sensor is considered to be an event, comprising the steps of:

• starting an observation interval for observation of events in a sequence of events;
• checking whether an event occurred within the observation interval;
• upon occurrence of an event within said observation interval, counting the event, terminating the observation interval, and initiating a further observation interval to establish a sequence of said observation intervals, there being no more than one event per observation interval;
• counting further events occurring within further intervals of said sequence of observation intervals;
• measuring a magnitude of the signal of an event occurring subsequent to attainment of a predesignated count in said counting step;
• and
• actuating said device upon attainment of a predetermined signal magnitude in said measuring step.