Screaming Garden Gnome Prank
Gavin Scott modified a garden gnome with Arduino to play audio clips whenever it's picked up.
Garden gnomes can be a fun way to decorate your lawn or even the inside of your house, but at the end of the day they just kind of sit there. However, since you expect them to be inanimate objects, and because they generally have a cavity on the inside, they can be augmented with electronics for unexpected hijinks.
Here Gavin Scott of the Make Fun Stuff YouTube channel places electronics within the little garden gnome, including a speaker, amplifier, and Adafruit FX Mini Sound Board to take care of playing audio clips. The original plan was to use a simple microswitch to trigger the gnome to make a sound when picked up, however, Scott didn’t feel like he could fixture it to the bottom for reliable triggering. He instead utilized an LDR light sensor, which meant adding an Arduino Nano. Code and a wiring diagram are available here.
All of this, along with batteries and an on/off switch was a tight fit, but it did eventually work, and was placed at his friend Kevin’s door as part of a long running “gnome war” between the two. As seen at the end of the video, he seems quite confused by the gome's arrival, which screams when picked up. Given their history, he certainly figured out its origins before too long, and perhaps a newly-augmented gnome will make its way to Scott in the future!