A Physical Rickroll Device
rroll is an open source Arduino project that uses an ultrasonic sensor to unleash cheesy music on unsuspecting passersby. Whenever someone enters within 6 feet of the sensor, the device is activated and starts playing Rick Astley's Never Gonna Give You Up. When the person leaves the area, the music pauses, only to resume where it left off when the person re-enters the area.
If you've never heard of it before, a Rickroll is a bait-and-switch Internet phenomenon where someone will post an interesting or shocking headline designed to catch people's attention, only to play Rick Astley's Never Gonna Give You Up when the unsuspecting visitor clicks the link.
The device is powered entirely off of batteries so it can be hidden in the most obscure of places. I hot glued the components into place inside the casing to make a semi-permanent device. This will allow it to be jostled around without falling apart.
You can see a video of the device in action here: https://www.youtube.com/watch?v=e-l3jg13Pdk