Entry way / Area motion activation

For a door or area that is always open, you can use infrared motion detection or a narrowly focused infrared beam between two sensor devices, one producing the beam and one reflecting or receiving the unbroken infrared beam.  The entry alert or chime occurs when someone moves in the protected area or opening or breaks the invisible infra red beam. When the beam has been broken or movement has occurred in the protected area, an alert sound is made and/or sent to a wireless receiver (where the alert is sounded) in another area or room.