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. ... to ~38kHz signal yielded by D9 of the ...

[Maker 101] gave the Arduino an infrared sensor which can pick up signals from a simple IR remote control. It can be driven backwards and forwards or turned left and right.

In the real world, missile systems use advanced radars, infrared sensors, and other hardware to track and prosecute their targets. [Raspduino Uno] on YouTube has instead used ultrasound for targeti… ...