Now let us move on to some significant points to consider while using the 2Y0A21 general purpose type distance measuring sensor. Due to the trigonometry ... true adapter circuit diagram below. A ...

To measure wind speed and direction ... [Andy] demonstrates building an ultrasonic anemometer using a cheap after-market parking distance sensor kit and an Arduino. Demo video after the break.

[mircemk] shows how to create a simple non-contact proximity sensor using little more than an Arduino Nano board, and a convenient software library intended to measure the value of capacitors.