| 摘要 |
The invention relates to a device for operating a windscreen wiper with an automatic wiper control which comprises a rain sensor with a light-emitting transmitter diode SD, a receiver ED which responds to the emitted light and transmits a sensor signal, and an evaluating device for the sensor signal comprising a micro computer. An evaluation of the sensor signal is achieved simply and reliably in that the evaluating device comprises at least one capacitor C, which is provided outside the micro computer and to which the sensor signal is supplied, a comparator K is connected to the capacitor, which comparator compares the voltage formed in the capacitor by the sensor signal with a threshold voltage, and transmits an output signal if the threshold voltage is exceeded, and the micro computer forms a measurement value from the output signal corresponding to a time when the threshold voltage is exceeded. The device does not respond to ambient light changes, e.g. caused by trees along an avenue.
|
