An Infrared light beam is the best solution for outdoor surveillance. It is not depending on the surrounding temperature
(PIR motion detectors depend on the air temperature, the wormer the air is, the lower is the difference between body heat and air, and this reduce the sensor range.) This IR beam includes 2 components, the IR light transmitter, which works with 2 x AAA battery up to 1 year, and the IR beam receiver, which works with 12V net power.
The IR receiver is normally installed near the house, this offers good wireless signal transfer from the radio module inside the IR beam receiver, and the net power source is easily available. The distance between IR beam transmitter ( battery operated) and the IR beam receiver (net power operated) is up to 20 m, if a person pass the invisible IR beam, a wireless signal will be sent to the center in the house.
The IR beam components are small , the size is only 10 x 3,8 x 3,5cm.
The installation is very easy, soon when the invisible infrared light beam meets the receiver, a red LED will show the correct position of both components. The best mounting height is aboput 1,2 m (4 feet) over ground.
The delivery includes the 2 IR beam components, 2 x AAA battery,
1 x 12V power adapter and a 10 m DC cable, which can be extended by another 10m cable by plug connection.