These sensors are installed to provide additional detection for the intruder alarm. These sensors can be one of 3 types:
- Standard PIR (passive infrared) sensors which measure infrared light radiating from objects in its field of view.
- Dual Tec sensors which measure both infrared light and microwaves. These sensors provide an excellent detection rate and high immunity to false alarms and reduced call out costs.
- Sequential sensors which feature two non-overlapping detectors in one device.