He suspected EMF interference so as a quick first step he decided to throw together an EMF detector using an Arduino. It uses a bank of LEDs as an indicator bar to reflect the EMF picked up by the ...

Using motion detectors and an Arduino ... Motion Detector or PIR. These sense the infared radiation emitted by all objects above absolute zero. When something passes in front of a PIR sensor ...

With enough miniaturization, you could even build a very robust emotion detection system into a smartphone. Most phones already have cameras, microphones, and wireless capabilities.