RCWL0516 Microwave Distance Sensor Module with Arduino

Distance sensors are employed to measure the distance of the target by sending high frequencies. Microwaves are electromagnetic waves with VHF/UHF bands used for communication purposes. Short microwaves serve in sensing applications, especially in radars, alarm systems, and human body detection. RCWL0516 is a microwave distance sensor created to replace passive infrared motion sensors that utilize infrared light emitted by a moving person. RCWL0516 uses a doppler effect technique to sense moving objects.

This tutorial will discuss its components, pinout, configuration, features, specifications, interfacing, 2D model, and applications.

RCWL0516 Components

The following figure shows the components of an RCWL0516 module :

RCWL0516 Microwave Distance Sensor Module components

The module consists of an Input/Output block, an RCWL0516 IC and RF Antenna, and an Amplifier block with some optional connections.

RCWL0516 Pinout

Following is the pinout of the RCWL0516 Microwave Distance Sensor Detector Module :

RCWL0516 pinout diagram Microwave Distance Sensor Module

Pin Configuration

The pin configuration detail in tabular is mentioned below:

NumberPin NameFunction
13V33.3V output pin
2GNDGround pin
3OUTAnalog sensor output pin
4VINPower Supply pin
5CDSSensor disable pin

Features and Specifications

  • Input Operating Voltage: 4 – 28 Volts
  • Operating Frequency: 3.2 GHz
  • Operating Current : 2.8 – 3.0 mAmperes
  • Power Transmission: 20 – 30 watts
  • Output pin Voltage: 3.3 Volts
  • Output pin Current: 100 Amperes
  • Operating Temperature : -200C – 800C
  • Range : 3 – 7 meters
  • Some of the detailed features include:
  • The output pin is HIGH (3.3V) when a motion is detected.
  • The 3.3V output pin has a finite HIGH time of 2 -3 sec.
  • Outpin pin stays at LOW state if CdS(Photoresistor) pin is less than 0.7 Volts.
  • Wide operating voltage range
  • Devoid of the blind angle detection

 To check further technicalities, the link to the datasheet is provided at the bottom of the article.

Internal Circuitry

RCWL0516 internal circuit diagram

Input/Output Block: This block contains power supply pins and I/O pins connections to microcontrollers and other electronic components.

RCLW0516 IC: The IC is a system responsible for performing the doppler effect technique and is prone to fewer errors than PIR.

RF Amplifier and Antenna: An inbuilt antenna to capture the incoming waves with an amplifier to boost the module’s radio waves.

Capacitors and NPN Transistor: An NPN transistor alongside capacitors and an inductor produces oscillations at a particular high frequency. In simple words, it works as a Colpitts oscillator. The capacitors are also responsible for the decoupling and filtering of signals.

CDS: A pin to add up a light resistor to the module to make the module work only in darkness. It also functions as an enable/disable control.

C-TM, R-CDS, R-GN are used to alter the module according to the requirement. C-TM is used to elongate the trigger time of the pin by the addition of a capacitor.

To change the limit value of the photoresistor, R-CDS should be connected to a suitable resistor. Lastly, R-GN can help us to adjust the measuring distance of the sensor. Attaching it to a resistor can reduce the range of the sensor.

How does RCWL0516 work?

The integrated antenna captures and generates the microwave signals. When the antenna receives a reflected signal, it sends it to the mixer/amplifier. It mixes the transmitted and reflected signal, and the difference between them is then passed to the IC for processing. The IC will send an output voltage signal, which will showcase the distance between the body and the sensor.

Interfacing with a Microcontroller

It is straightforward to interface this motion detection sensor module with microcontrollers. For demonstration purposes, we will use an Arduino in this tutorial. Interfacing RCWL0516 with Arduino is by making connections. The wiring diagram is shown below :

RCWL0516 microwave sensor interfacing with Arduino

The pin configuration is as follows:

RCWL0516 ModuleArduino UNO
GNDGND
VIN5V
OUTD10

CDS pin provides an option to add a photoresistor to the module and make the sensor only operate in darkness. Make the wire connections accordingly. After making connections, upload the Arduino code. Open the Serial Monitor to observe the results. As soon as a motion is sensed, the serial monitor will display a message.

Arduino Code

When this motion detector sensor senses a motion, it triggers its output pin to active high state for 2-3 seconds and after that it goes to active low state again.

The digitalRead() function of Arduino is used to measure the active hig state. If you don’t know how to use Arduino digital pins, you should refer to this article:

int detectPin = 10;
bool detect = false;
int led = 13;
void setup() {
 Serial.begin(115200);
 Serial.println("Starting...\n");
 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);
 }
 delay(1000);
}

To see the output of the above code, upload the code to the Arduino board. After that, open the Arduino IDE serial monitor by selecting a baud rate of 115200. Now whenever there is a motion in front of the RCWL0516 microwave sensor, it will detect the sensor and display the “Movement detected” message on the Arduino serial monitor. Moreover, the onboard LED which is connected with D13 pin of Arduino also turns on.

RCWL0516 sensor output on Arduino terminal

RCWL0516 Alternative Options

  • SEN0192
  • HC-SR04

Applications

  • Home Automation systems
  • Radars
  • Intrusion alarm systems

2D Diagram

The following figure shows the 2d model of the RCWL0516 Microwave Distance Sensor Module. It shows us the physical dimensions of the components needed when a PCB card is designed.

RCWL0516 2D diagram

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