RCWL-0516 Microwave Radar Sensor Module

The RCWL-0516 Microwave Radar Sensor detects motion by emitting microwave (radio frequency) signals and sensing reflections from moving objects. Unlike PIR (Passive Infrared) sensors that need direct line of sight, the rcwl 0516 radar module detects movement through plastic enclosures, thin walls, and wooden surfaces. It outputs a digital HIGH signal at 3.3V when motion is present, which any microcontroller reads directly as a GPIO input.

The microwave radar sensor operates on the Doppler effect (a frequency shift caused by a moving object reflecting the microwave signal). One non-obvious detail — it also triggers on vibrations in nearby objects, not just walking people. A fan running behind a wall can cause false triggers in some installations. The honest limitation is that the rcwl-0516 datasheet gives no fixed adjustable sensitivity — the detection range is fixed by the PCB design and cannot be tuned easily through software.

The microwave sensor module connects to Arduino, ESP8266, ESP32, and STM32 through a single digital output pin. Learners building security alerts and making occupancy detectors both use it regularly. To start, wire VIN to 5V, GND to GND, and OUT to any digital input pin. StemVolt supplies this module tested with confirmed output response.

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Features:

• Microwave radar detection at 3.3V output triggers directly on any 3.3V or 5V GPIO input pin
• Operating voltage from 4V to 28V DC covers USB power banks, Arduino 5V, and 12V wall adapters
• Digital output HIGH signal at 3.3V stays active for approximately 2 seconds per detected motion event
• rcwl 0516 sensor detects motion through non-metallic surfaces making it useful in closed enclosures

Technical specifications:

Applications:

• Security alarm project uses this sensor to trigger a buzzer when someone enters a room
• RCWL-0516 Microwave Radar Sensor sends an SMS alert through a GSM module when motion is detected
• rcwl 0516 sensor counts people passing through a doorway using pulse counting on a microcontroller

Package includes:

• 1 x RCWL-0516 Microwave Radar Sensor