Anybody can go to the hardware store and pick up a motion activated light but that’s so 80’s and the only thing involved with installing them is talent with a screwdriver. Ultrasonic waves are better at tracking movement, at least when it comes to ninja attacks and other unseen entities, which is where Tinkernut’s Motion controlled Ultrasonic Lamp comes in. The lamp uses ultrasonic waves to not only detect movement but also the direction it’s coming from.
The lamp is outfitted with three ultrasonic sensors housed in a control box that sits underneath the lamp itself, which uses to servos to move in the direction of the sound it detects. Those sensors are connected to a simple breadboard with an Arduino Uno running the show. A double-A battery pack powers the unit, which is toggled on/off using a simple switch.
Obviously, the lamp is nothing without the code to run it and Tinkernut provides everything users need to get the ball rolling. Will it actually detect ninjas? If they’re worth their salt, yes. You can never be too careful. See the plans after this link.