My dorm at Arizona State University decided to have a door competition for halloween. One of the prizes was a brita water filter. At ASU, water is absurdly expensive- two dollars for a gallon at the cheapest. I decided I was gonna win this filter.
A shoebox that was rigged with a Passive Infrared Sensor (PIR) and a set of speakers. When people triggered the PIR motion sensor by walking past, the speakers said one of three spoooky things: ASU is number two in innovation, your M&G balance is 0, and just chemistry
I used a Sparkfun Redboard to build this. On start, the redboard interfaces a SD card that had three audio files on it. Once someone triggers the PIR sensor by walking past, it pulls one of these files and plays the spooky phrase on the speakers.
Believe it or not, most people were not as motivated for that brita filter. I won the door competition and I didn’t pay for water the rest of the year.