Device for operating a windshield wiper
First Claim
1. In an apparatus for operating a windshield wiper having an automatic wiper control comprising a rain sensor having a light-emitting transmitter, a receiver that responds to emitted light by emitting a sensor signal, and an evaluation device for the sensor signal, said evaluation device including a microcomputer, at least one capacitor outside of said microcomputer, and to which the sensor signal is supplied to charge the capacitor, and control circuit means, controlled by the microcomputer, for enabling charging of said capacitor by the sensor signal at a desired point in time, a comparator connected to said capacitor for comparing the voltage built up at said capacitor over time by the sensor signal to a threshold voltage and for emitting an output signal, corresponding to the integral over time of the applied sensor signal, if the threshold voltage is exceeded, said microcomputer forming a measured value from the output signal, the value of which corresponds to a period of time for the built up voltage to exceed the threshold voltage.
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Accused Products
Abstract
An apparatus for operating a windshield wiper having an automatic wiper control. The apparatus is provided with a rain sensor having a light-emitting transmitter and a receiver that responds to the emitted light by emitting a sensor signal, and an evaluation device for the sensor signal. The evaluation device has a microcomputer and a capacitor that is outside of the microcomputer and to which the sensor signal is supplied. Also included is a comparator connected to the capacitor for comparing the voltage built up at the capacitor by the sensor signal to a threshold voltage and for emitting an output signal if the threshold voltage is exceeded. The microcomputer forms a measured value from the output signal, the value of which correspond to a time at which the threshold is exceeded.
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Citations
11 Claims
- 1. In an apparatus for operating a windshield wiper having an automatic wiper control comprising a rain sensor having a light-emitting transmitter, a receiver that responds to emitted light by emitting a sensor signal, and an evaluation device for the sensor signal, said evaluation device including a microcomputer, at least one capacitor outside of said microcomputer, and to which the sensor signal is supplied to charge the capacitor, and control circuit means, controlled by the microcomputer, for enabling charging of said capacitor by the sensor signal at a desired point in time, a comparator connected to said capacitor for comparing the voltage built up at said capacitor over time by the sensor signal to a threshold voltage and for emitting an output signal, corresponding to the integral over time of the applied sensor signal, if the threshold voltage is exceeded, said microcomputer forming a measured value from the output signal, the value of which corresponds to a period of time for the built up voltage to exceed the threshold voltage.
Specification