Read the automatic windshield wiper patents described in Flash of Genius. They provide circuit diagrams and explanations of why the wipers move faster when there's a lot of rain.
And you think it shouldn't have been patentable if it instead used a microcontroller to control the wipers even though the system is doing the same thing?
Read the automatic windshield wiper patents described in Flash of Genius. They provide circuit diagrams and explanations of why the wipers move faster when there's a lot of rain.