I recently had to build an infrared close proximity sensor that could tell if something was dropped in a parcel delivery drop box. After some searching, I ...

Arduino Based Wireless Intrusion Detection Using IR Sensor and GSM Intrusion Detection Systems (IDS) strive to catch computer system intrusion & utilize by any garnering and analyzing data.

The part list consists of one Arduino, two resistors, and one IR emitter. That’s right, an emitter. When an LED (IR or otherwise) is reverse biased it can act as a light sensor.