Parking sensors have become a must-have these days given the crowded cities we live in, but instead of paying hundreds of dollars to get them installed in your car, why not building your own at home?

autoevolution: Super-Cheap Parking Sensors Built at Home with an Arduino. https://www.autoevolution.com/news/super-cheap-parking-sensors-built-at-home-with-an-arduino-142445.html