This tutorial will guide you through the process of building a tachometer around an Arduino. Tachometers are used to measure rotation rate in Revolutions Per Minute (RPM). You don’t need much… ...

How it works: When something triggers the sensor, the Arduino records that moment as triggerTime in Line 23, and compares it with the current time based on conditions in lines 26, 29, and 34.

TK has combined a PIR with an Arduino to create a smart safety light for the house or workshop. Follow along as this gets built out into a more extensive project.

If you've always wanted to try to build an Arduino project, this may be a great way to start. Matt Williamson built a tiny, Arduino-based motion sensor that will SMS you when something moves by ...

Using motion detectors and an Arduino you can trigger lights, fans, or even an pneumatically controlled cleaver-wielding clown to help add your house to the “if you dare” list.

The project’s goal — in excess of a lighting solution for an entrance hallway — was the learn the ins and outs of the Arduino and motion sensors.