The RCWL-0516 is a Doppler radar microwave motion sensor. Based on the Doppler effect, Doppler radar works by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. It has a sensitivity range of seven meters.

The microwave sensor has several advantage over other detection methods. It can detect moving objects behind thin walls and behind other materials such as wood. It can work from inside a case, meaning it can be stored in a waterproof case and remain safe and dry. Other advantages are that readings not affected by temperature, day, night, humidity, noise, air, dust or light, making it suitable for harsh environments.

So, what can the RCWL-0516 be used for? It can be used to detect animals or humans entering a room or open space, or activate a robot when it detects a user.

Featrures

Transmit power: 20 - 30 mW
Voltage input: 4–28 VDC
Sensing Distance: 5–7 m
Frequency: ~3.2 GHz

RCWL-0516 sensor Datasheet.

Microwave Motion Detection Sensor (RCWL-0516) detailed tutorial including arduino connection and code.

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