Interactive Halloween props are always fun and they are surprisingly easy to make. This year I designed a simple system that rotates a skull to face you and follows you movements as you walk by.
To accomplish this I used light sensors to detect a person's shadow. An Arduino microcontroller then calculates where they are standing and activates a servo that turns the skull to face them. When they move, the skull turns to follows them.
Learn how to use solar panels for both battery charging and for sensing when light has dropped below a certain threshold. Learn how to use an Arduino Micro for power management, and combine these two skills into an exciting classic "cricket" noisemaker that only turns on when the sun has faded into the night.
Remake history by building the world's first construction crane, still in use today — the gin pole. In antiquity, the only way to raise a heavy object was to put a rope on it, climb a ladder, and pull — or if you had enough time, build a ramp. Then the Greeks put a pulley on a pole, and the sky was the limit.








