Automotive Rain Sensor Wiper

Automotive Rain Sensor device functions as a versatile automatic wiping of a vehicle’s windscreen when it is wet due to moisture, raindrops or even mud. Operation is based on harmonious light beams reflection within the windscreen. Any disturbance in harmonics will create drop or increase in light beam intensity causing the system to activate the wipers in a fully automatic manner.

The most important front end of this device is the OSRAM’s silicon PIN photodiode which senses the change in light intensity or wavelengths due to incident light on the windscreen caused by biasing with the water drops. The high precision PIN photodiode will generate out different amount of current or voltage level with respect to the different light property changes sensed.

The amplified yet conditioned signal in analog form will be fed into a simple 8-bit Microcontroller’s(MCU, Philips LPC767 or LPC768) built-in 8-10 bit resolution (255 – 1024 step levels) Analog-to-Digital Converter for sampling with careful software debouncing techniques implementation. The digital processing task is carried out by the MCU to determine the level of raindrops or water amounted on the windscreen. This is solely based on a predetermined look-up table programmed much before hand. The look-up table can be stored in a non-volatile state under the included EEPROM. Different look up tables can be either updated by the MCU OR pre-programmed to suit a different earth regional climate environment.