Finally finishing up my first Arduino project which adds dynamic turn signals and a pulsed brake light to the unlighted rear reflectors in the Mk3 Focus RS. The pulsed brake lights are intended to grab the attention of distracted drivers. They won't flash again if the brakes are used within 10 seconds (adjustable.) This helps address the complaint some have when following vehicles in heavy stop and go traffic with aftermarket pulsed brake lights.
This project takes 12V signals tapped from the tail lights and passes them through an RC filter to clean up the dirty automotive signal, then into an optocoupler where the signal is dropped to 5V for the Arduino Nano. The Arduino takes these as di...