HEXA

ELECTRICAL

108

RAIN LIGHT SENSOR SYSTEM

RAIN LIGHT SENSOR

DESCRIPTION:

RAIN SENSOR:

It is an optical system, which

operates in the infra-red wavelength range. The

sensor houses 6 infra-red LED’s forming a

segment of a circle around a receiver diode.

Any rain drops landing on the windscreen in the

sensitive area of the sensor cause spontaneous

imbalance in the reflection, which results in

production of a voltage with the clocking frequency

of the LED’s. These brief deviations are detected

by an electronic analyzer and output as digital

pulses. The pulse duration is a measure of droplet

size whereas the number of pulses is a measure of

the number of droplets.

LIGHT SENSOR:

The Light / Tunnel Sensor is a

optical system. It operates with different optical

receiving diodes. The two receiving diodes A, B

have different characteristics.

Diode A is used to measure the global ambient

light.

Diode B has a beam in forward direction of the car.

BLOCK DIAGRAM: