I made the scariest pumpkin ever! Nothing gory or disgusting, just something that will scare the kiddies and hopefully score me some candy. How? Well, I am glad you asked. I rummaged through my parts bins and came up with an idea. What if I connected a horn to an Arduino and let out a nice blast when someone came around trick-or-treating. Hopefully they are so scared they drop their bag-o-candy and run away, leaving me with plenty of treats.
Note: The key to this project is the delay. You could just wire the horn to the button and I am sure you would get a lot of people to jump. Add a delay to the horn and when they turn their back, the real fun begins! Honk!