Smart Windshield Washer Sensor
Problem: The "intermittent" wiper setting on my car is often not the right speed. When the rain lets up, it's still too fast and the wiper scrapes. When the rain starts to get harder, it's too slow and I can't see. When I slow up or slow down, the wiper speed doesn't.
Solution: Have a small photo sensor sitting inside the window pointing outside, at a place that is covered by the wiper but not in the view of the driver. The photo sensor sends data to a smart processor - that estimates the rain that's hitting the window and adjusts the wiper blade speed. It could "watch" the wiper blade go by to calibrate the settings of a clear, recently wiped window versus the build up of rain drops between wipes.
Reward: Want one.