CDM324 24GHz Microwave Radar Sensor Module, Human Motion Detection Induction Switch, Doppler Presence Sensor for Smart Automation

The CDM324 24GHz microwave radar sensor module is a compact motion detection solution designed for smart automation, security systems, and DIY electronics projects. Unlike traditional PIR sensors that rely on infrared heat changes, microwave radar sensors detect motion by emitting microwave signals and analyzing the reflected Doppler shift. This method can provide more consistent detection in many conditions and can sense motion through certain non-metallic materials such as plastic enclosures, thin boards, or lamp shades—making it useful for hidden or integrated installations.

This module is commonly used as a human body motion detection induction switch, triggering an output signal when movement is detected within its sensing zone. Because it’s radar-based, it can be a strong choice for applications where PIR sensors struggle, such as detecting motion with small temperature differences, in cooler environments, or where you want the sensor concealed behind a cover (as long as the cover is microwave-transparent).

The CDM324 is well-suited for IoT and automation projects. You can pair it with a microcontroller like Arduino or ESP32 to trigger smart lights, activate fans, send alerts, or log occupancy events. In security applications, it can be used to trigger alarms or cameras when movement is detected. In home automation, it can support energy-saving routines by switching devices only when motion is present.

Important notes for best results: microwave sensors can be more sensitive than PIR and may detect motion through thin materials. Placement matters. Avoid pointing the sensor toward moving fans, vibrating machinery, or areas with frequent movement behind walls if you want fewer false triggers. If your project needs stable “presence” logic, add software filtering (debounce/time delay) to prevent rapid triggering.

Typical use cases

• Smart light motion activation (indoor corridors, stairs, storage rooms)
• Security detection triggers for alarms or cameras
• Automatic appliance control (fans, exhaust, air fresheners)
• Occupancy sensing for IoT energy-saving systems
• Hidden sensor installations behind plastic covers or inside enclosures

Specifications

• Product Type: Microwave radar motion sensor module
• Model: CDM324
• Operating Frequency: 24GHz
• Detection Method: Doppler radar motion sensing
• Output: Digital trigger output (logic depends on module design)
• Supply Voltage: Depends on module variant (verify pin label / seller spec before powering)
• Interface: Pin header connection (typical VCC, GND, OUT; may vary)
• Detection Characteristics: Can detect motion through some non-metal materials; sensitivity depends on placement and environment
• Applications: Motion-activated lighting, security alarms, smart automation, occupancy triggers
• Notes: Actual detection range and stability depend on mounting position, surrounding materials, and environmental movement.

If you want a compact, modern motion sensor for smart devices or DIY automation, the CDM324 24GHz radar module offers fast response and flexible installation compared to traditional PIR-only solutions.

Included Components
CDM324 24GHz microwave radar sensor module