Motion detectors are widely implemented in the design of intruder alarm systems. While these detectors in their raw state can have high detection sensitivity, this comes at the expense of generating higher false alarm rates. The most popular motion detection techniques implement either Passive infrared motion sensors or Active Continuous Wave Microwave Doppler motion sensors. Motion detectors using Dual Detectors employing both Doppler Microwave (MW) and Passive Infrared (PIR) motion sensors provide a new performance level where the feature of both sensors are combined while avoiding the disadvantages of both. The sensors are combined through a microprocessor to provide” intelligent “motion detection system designed to greatly reduce or eliminate “single detector” false alarm. A peripheral Integrated Controller (PIC) based on the popular 8051 device manufactured by Cygnal Corporation the C8051F020 has been chosen in order to reduce designed hardware complexity and utilize the improved features of this device to obtain better system performance. The PIR and Doppler Microwave detection systems are each designed as independent motion detectors. The PIC receives signals from these two sensors in addition to a third signal from a light sensor. The PIC compares the received signals against pre-stored values, double checking their existence in addition to dynamically selecting threshold detection levels depending on weather the motion detection system was operating in day light or at night. The result is a detector with a higher performance in terms of accuracy and detection certainty. The designed system has a large room for continued performance enhancements and features addition that can lead to designing a motion detection system that can fulfill every security system requirement.