RCWL0516 Microwave Distance Sensor & Its Working

RCWL0516 microwave distance sensor is mainly designed to replace PIR sensor that uses IR light which is generated through a moving person. So, this kind of sensor uses a Doppler Effect method to notice the moving objects.

Generally, the main function of a distance sensor is to measure the target distance by transmitting high frequencies. The electromagnetic waves like Microwaves are available with UHF (ultra-high frequency) and very high frequency (VHF) bands which are used for communiqué purposes. Short microwaves are mainly used in sensing applications like alarm systems, detection of the human body & radars.

What is RCWL0516 Microwave Distance Sensor?

The microwave radar sensor like the RCWL0516 module is an alternative to the passive infrared motion sensor. This sensor is used extensively in security lights, burglar alarms, etc. Similar to the PIR, this kind of sensor detects simply movements in the range of its detection.

This kind of sensor mainly uses a microwave Doppler radar method to notice moving objects rather than sniffing the radiation of a blackbody from a moving person. The sensitivity range of this sensor is approximately seven meters.

Once this sensor is activated then the TTL-level OUT pin will toggle from low voltage to high for a fixed time before returning to its inactive condition.

This sensor is very flexible to use in conjunction with several microcontrollers. It operates anywhere with a power supply ranges from 4 – 28 V. The output pin of this sensor is used for different tasks like driving a visual/ aural indicator otherwise even connecting with 3V microcontroller I/O for additional processing.


In construction, keep away from any metal element before the sensor module by maintaining 1-cm clear space on the front & backside of the sensor module.

Pin Configuration

The pin configuration of the RCWL0516 microwave distance sensor module is shown below. This sensor module includes 5 pins where each pin and its functionality are discussed below.

RCWL0516 Module Pin Out
RCWL0516 Module Pin Out
  • Pin1 (3V3): This pin is a regulated 3.3V o/p pin
  • Pin2 (GND): This is a GND pin
  • Pin3 (OUT): This is an analog o/p pin of the sensor
  • Pin4 (VIN): This is an input voltage [in for the sensor module
  • Pin5 (CDS): This is a disabled pin of the sensor

Features & Specifications

The features & specifications of the RCWL0516 microwave distance sensor module include the following.

  • Input voltage ranges from 4 to 28V
  • The limited-time of 3.3V o/p pin is 2 to 3 sec.
  • The operating frequency is 3.2 GHz
  • Once motioned is sensed, then the o/p pin is maximum like 3.3V
  • Operating current ranges from 2.8 to 3.0 mA
  • Power transmission ranges from 20 to 30 watts
  • Range of distance from 3m to 7m
  • The voltage of the o/p pin is 3.3 V
  • Operating temperature ranges from -200C to 800C
  • The current of o/p pin is 100 A
  • Output pin waits at LOW condition if photo resistor pin is low as compared to 0.7 V.
  • Adjustable distance & block time
  • Penetrating detection ability

The RCWL0516 microwave distance sensor module includes an I/O block, an RF Antenna, an Amplifier block including some connections, and RCWL0516 IC. An alternate RCWL0516 ICs are; SEN0192 & HC-SR04.

The antenna within this sensor module will capture & produce the microwave signals. Once the antenna gets a reflected signal, then it transmits to the amplifier or mixer. So it combines the signal which is transmitted & reflected. The disparity between these two is supplied to this IC for further processing. The RCWL0516 IC will transmit an o/p voltage signal, which will display the distance between the sensor & the body.

How to use/Circuit Diagram

The RCWL0516 module output is analog & it is connected to the microcontroller’s analog input & it can be sampled through an analog to digital converter. The o/p voltage is approximately comparative to the distance between the object & the sensor.

But, when it depends on a Doppler system, the reflections of signals from other nearby objects can connect through the measurement to make it less dependable & correct as compared to other sensors.
The reflections of signals from various objects can affect measurements like the reflection of metallic objects is very stronger as compared to plastic.

How to Interface RCWL0516 Microwave Distance Sensor with Arduino

Interfacing of RCWL0516 microwave distance sensor module with an Arduino microcontroller is straightforward. Here, the following interfacing diagram is shown for demonstration purposes. The interfacing of the RCWL0516 Module & Arduino UNO can be done directly to the following pins.

RCWL0516 Module Interfacing with Arduino
RCWL0516 Module Interfacing with Arduino
  • The GND pin of this sensor is connected to the GND pin of the Arduino
  • The VIN pin of this sensor is connected to the 5V pin of the Arduino
  • The OUT pin of this sensor is connected to the D10 pin of the Arduino

Here, the CDS pin provides an alternative to include a photoresistor toward the sensor module to make this sensor operate simply in darkness. As per the connections given above, we need to make the connections. Once the connection making is done, need to dump the Arduino code.

The results can be viewed by opening the serial monitor. Once a motion is detected, the serial monitor will show a message.

Once this sensor detects motion, it activates its o/p pin toward active high condition for few seconds then again it enters into active low condition. Here, the active HIGH state is measured through the function of digitalRead(). Arduino code is shown below.

int detectPin = 10;
bool detect = false;
int led = 13;
void setup() {
pinMode (detectPin, INPUT);
pinMode (led, OUTPUT);
void loop() {
detect = digitalRead(detectPin);
if(detect == true) {
digitalWrite(led, HIGH);
Serial.println(“Movement detected”);
else {
digitalWrite(led, LOW);

The output of the above code can be observed by uploading the above code into the Arduino board. Afterward, need to open the serial monitor of Arduino IDE by choosing a baud rate like115200. Once the motion is detected in front of this sensor, then it will show the message like the “Movement is Noticed” on the serial monitor. In addition, the LED on the Arduino board is connected through a D13 pin also activates

Where to use/Applications

The applications of the RCWL0516 microwave distance sensor include the following.

  • Detecting the distance
  • Radar applications
  • Home Automation systems
  • Alarm systems for Intrusion

Thus, this is all about an overview of the RCWL0516 microwave distance sensor datasheet which includes its pinout, specifications, features, interfacing, and applications. Here is a question for you, what is the function of an Arduino board?