[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.

This tutorial will guide you through the process of building a tachometer around an Arduino ... calculate RPM. Another alternative would have been to use a reflectance sensor which allows to ...

Now that you've seen how to blink your Arduino's LED, we'll use one final, slightly more complex example: we'll use a third-party UNO breakout board and an external traffic light sensor board to ...