[Klaus] wanted some sort of aid for parking his car, and after running across a $4 ultrasonic sensor, decided to build his own speaking distance sensor (.de, Google Translation). Inside [Klaus ...

Inside the light is an Arduino Nano, which reads from the ultrasonic sensor mounted underneath the enclosure and lights up the appropriate LED depending on the car’s distance.

A low-cost (~$100), do-it-yourself (DIY) ultrasonic water level sensor/datalogger has been designed, constructed, and tested for use in education, citizen/community science, and research settings. The ...