IR sensor for automatic wiper system

[lokejeehan]

Hi, I am doing automatic wiper system for car. I need a IR transmitter and receiver for me to detect the rain water on the windscreen, is this suitable? I need something to transmit IR on an area of around 10x10 cm and receive all the data after reflected by the screen

[yonghui]

i think IR is not that suitable for detecting rain. rain drops are clear transparent. IR operates on reflection. and IR is affected by light from environment. its quite hard to set threshold for the rain drop.