The Etch a Sketch toy has gone more or less unchanged for over 60 years, but if you’re handy with a soldering iron you can build an upgraded version that swaps aluminum powder for glowing LEDs.

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.

4. PIR Motion Sensor Motion sensing is useful for a range of applications, from intruder detection to home automation. PIR motion sensors use infrared light to detect movement.

Here, the code is in the form of an Arduino sketch, and hence, you can try a “free” Attiny85 chip in lieu of the Digispark board for a commercial translation. It should be a piece of cake if you ...

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 Leap Motion controller is a rather impressive little sensor bar that is capable of generating a massive 3D point cloud and recognizing hands and fingers to allow for gesture control based compu… ...

You'll definitely need some gear for it—the Arduino for one, but also a PIR motion sensor, not to mention the (cleaned and rinsed!) Raid Power Sprayer motorized spray bottle.