Wireless Dual Microwave PIR Detector DAHUA ARD2251E-W2 868 – wireless motion detector, dual-technology (microwave + PIR), 868 MHz

DAHUA ARD2251E-W2 868 is a wireless dual-technology motion detector that combines passive infrared (PIR) and microwave sensing on the 868 MHz frequency. Designed for perimeter and indoor intrusion detection, this detector requires simultaneous confirmation from both sensor types to register movement, which helps reduce false alarms caused by environmental factors. The device is compatible with alarm systems supporting 868 MHz wireless devices and is intended for reliable motion detection in residential, office and commercial environments.

Advantages

The combination of microwave and PIR sensing improves detection accuracy by validating movement across two independent technologies. Wireless operation on the 868 MHz band enables flexible placement without extensive wiring, and the compact housing simplifies installation in a variety of indoor and sheltered perimeter locations. The detector’s dual-technology approach provides improved immunity to pets, drafts and temperature changes compared with single-technology sensors, reducing unnecessary alarm events.

Suitable for

• Perimeter protection for entrances, corridors and external sheltered passages
• Indoor intrusion detection in homes, offices and small commercial premises
• Integration with compatible 868 MHz wireless alarm control panels and receivers
• Locations where reduction of false alarms is important due to environmental or animal activity

Key specifications

• Detection technologies: microwave and passive infrared (PIR)
• Operating frequency: 868 MHz (wireless communication)
• Detection method: dual-technology logic requiring both sensors to trigger
• Intended mounting: wall or corner mounting for perimeter and indoor coverage
• Typical coverage: designed for short- to medium-range motion detection in sheltered locations
• Power: battery-powered wireless operation (check compatible battery types and expected lifetime with system documentation)
• Environment: for indoor use and sheltered outdoor locations; not designed for continuous outdoor exposure without protection

How to use

Mount the detector at the recommended height on a stable surface, oriented to cover the intended detection zone while avoiding direct exposure to heating sources, air vents or reflective surfaces that could affect the PIR or microwave sensors. Follow the alarm system manufacturer’s pairing procedure to enroll the device on the 868 MHz network, then perform an acceptance test to verify detection across the protected area. Adjust aiming or placement if the detector fails to reliably detect movement across the desired coverage.

Usage recommendations

For optimal performance, install the detector away from direct sunlight, heating units and large moving objects such as curtains or trees. When used in areas with pets or frequent environmental changes, position the detector and configure the system to balance sensitivity and false-alarm reduction. Consult the alarm control panel documentation for recommended placement, battery replacement intervals and specific enrolment steps for 868 MHz devices.