Intruder detectors decide the reliability of the alarm systems. To avoid the interference, anti-detection of fault alarm and missing alarm, multiple techniques are used in detector designing. 
1. Micro-wave sending time will be staggered when one more detectors are operated synchronously.So, maximum 4 pcs MW & PIR detectors can be installed in one room. 

2. PET immunity:
The infrared signal detected will be stored and compared with human body signal and excluded pet movement alarm.

3. Two infrared sensors are used to detect motion. 
 The signal detected will be stored in RAM and will be calculated by logical addition, 
then the result and original signal will be compared to judge whether or not it is true alarm. 

4. Anti-detection design: When the detector is set at anti-detection mode, CPU will analyze the weak signal detected and if it found it is anti-detection,
It will active the micro-wave sensor to detect, and logical calculate both signals to judge. 

5. Auto temperature compensation design to avoid environment temperature change. 

6. Two infrared sensors are built-in. Motion sensors detected are same polarity and RF, 
electric magnetism, static electricity interference are opposite polarity. 
So, it can anti interference. 
 
7.Micro consumption current designed for long life battery usage.