Design of infrared sensor for vehicle rainfall based on ZEMAX

The optical structure design and simulation of vehicle rainfall sensor are carried out with ZEMAX. Two groups of six infrared LED for star-shaped layout. The design of incident Angle of infrared pulse light is greater than the critical angle of total reflection when there is no rain and each group of infrared LED works at a certain time sequence. The rainwater on the windshield of the car changes the refractive index of the emitting medium of the pulsed infrared ray, which causes the attenuation of the luminous flux of the receiver's infrared ray and the detection circuit will generate impulse signal. Using fast Fourier transform and fuzzy control technology, the output signal of different windshield rainfall is given, and the output signal is communicated with the body control computer by the built-in LIN bus module of the single-chip microcomputer, so as to realize the automatic control of the windshield wiper in the driving rain and accidental muddy water splashing.