Takex
The technology of sensors, security equipment to detect intrusion or activate alarm, is increasingly advanced, 
Takex, for example, has manufactured the PB-50/100/200F models, which have two optical filters and a special filtering circuit for a real tolerance of 50,000 Lux against natural or artificial light.
These models are 4 beams with "and" (Y) firing logic that avoid false alarms before falling leaves and bird flight. The 4 beams must be invaded simultaneously to create the sensor alarm.
Similarly, its active infrared transmission is exceptionally strong with a maximum range ten times greater than that specified for its protection distance, which is 50m (outdoor)/100m (indoor) for the PB-50F, 100m/200m for the PB-100F and 200m/400m in the PB-200.
Among other features, they also incorporate programmed AGC function, to increase sensitivity to bad weather conditions; protection against insects; and indicators for beam alignment, both sound and visual.
