Arduino Projects

Arduino RCWL-0516 Microwave Sensor or the DFrobot Digital Microwave Sensor V2.0

RCWL-0516 Microwave Sensor:


Arduino RCWL-0516 Microwave Sensor or the DFrobot Digital Microwave Sensor V2.0I have got two digital microwave sensors designed for the same job and uses the same doppler radar to detect moving objects using microwaves. The one on the left side is the RCWL-0516 Microwave Sensor which is smaller in size and it’s really cheap.

While the one on the right side is the Gravity Digital Microwave Sensor V2.0 from the Dfrobot which is bigger in size and obviously it’s more expensive than the RCWL-0516 microwave sensor

I have already used the Gravity Digital Microwave Sensor V2.0 for controlling lights, for detecting humans behind the walls, and recently I used this sensor to create an invisible security system. It has exceeded my expectations. So, If you are Ok with its price then just go for it, it works flawlessly.

But, if you are more into saving money and you are ok with 6 to 7 meters detection range then you can start with the RCWL-0516 Microwave Sensor. Right now, I don’t know if it can detect moving objects and humans behind the walls, and this is what we are going to find out. So, without any further delay let’s get started.

Amazon Links:

Arduino Uno

Arduino Nano

RCWL-0516 Microwave Sensor

Gravity Digital Microwave Sensor V2.0

Other Tools and Components:

Top Arduino Sensors:

Super Starter kit for Beginners

Digital Oscilloscopes

Variable Supply

Digital Multimeter

Soldering iron kits

PCB small portable drill machines

*Please Note: These are affiliate links. I may make a commission if you buy the components through these links. I would appreciate your support in this way!

RCWL-0516 Microwave Sensor:

Arduino RCWL-0516 Microwave Sensor

The RCWL-0516 Microwave Doppler Radar is a type of motion sensor that uses Microwave Radar Technology to detect moving objects, humans, and animals. It is an alternative to PIR motion sensors which are commonly used in security systems and in automatic lights control systems. The RCWL-0516 microwave sensor has a sensitivity range of up to 9 meters as per the datasheet. When this sensor is in the idle state means when there is no moving object it gives 0 volts or LOW output signal and when triggered, it’s output pin will switch from LOW (0V) to HIGH (3.3V) for around 2 to 3 seconds before returning to its idle state.

This microwave sensor is based on the RCWL-9196 chip that supports repeat trigger, and 360 degrees detection area with no blind spots.

Arduino RCWL-0516 Microwave Sensor Specifications:

Input Voltage: 4-28VDC @ <mA

Detection Range: ~5-9m

Frequency: ~ 3.2GHz

Transmitting Power: 20mW (typical); 30mW (max)

Output Level: ~3.4V High <0.7 Low

Output Drive: ~100mA

Output Timing: ~2sec Retrigger with motion

Operating Temperature: -20~80 Celsius

Storage Temperature: -40~100 Celsius

Terminals: 0.1 Pitch solder holes

L: 1-3/8” W: 13/16” H: 3/16” WT: .005

RCWL-0516 Microwave Sensor Pinout:

RCWL-0516 Microwave Sensor Pinout

All 5 pins are clearly labeled.

  • This 3V3 pin is a 3.3V Output, this is not a power supply input. This board has an onboard 3.3V regulator that can provide up to 100mA for powering external logic circuits.
  • The GND pin should be connected to the GND pin of the controller board.
  • The OUT pin gives 3.3 volts when a moving object is detected. So it means it can be used with all 3.3V compatible controller boards like ESP8266, STM32, ESP32, RASPBERRY PI PICO, ARDUINO PRO MICRO, and so on.
  • The VIN pin is the Input power pin and it accepts a wide range of input voltages between 4 and 28 volts.
  • The CDS pin is for the light sensor LDR, light dependent resistor. This is optional, if you don’t want to add an LDR it’s okay.

But, if you want to use it outside for security purposes or for controlling lights and you don’t want this sensor to trigger its output during the daytime then it’s good to add an LDR.

Optional Adjustments:


Trigger (Output Pulse) cycle time: The default (unpopulated) time is 2s. Adding a SMD capacitor will extend the repeat trigger time. The IC emits a frequency (f), and the tigger time in seconds is given by (1/f) * 32678


Detection Range: The default detection range is 7m, adding a 1M resistor reduces it to 5m


Light sensitivity adjustment. Part of the voltage divider for the optional Photoresistor. Lower R-CDS, the brighter it has to be to disable the trigger. (47K–100K)


Mounting location for an optional on-board Photoresistor for disabling output trigger in daylight.

So, that’s all about the technical specifications and Pinout. And now we can start with the interfacing.

Altium Designer + Altium 365 + Octopart:

Arduino LoRa Free SMS

Altium 365 lets you hold the fastest design reviews ever. Share your designs from anywhere and with anyone with a single click. it’s easy, leave a comment tagging your teammate and they’ll instantly receive an email with a link to the design. Anyone you invite can open the design using a web browser. Using the browser interface, you’re able to comment, markup, cross probe, inspect, and more. Comments are attached directly to the project, making them viewable within Altium designer as well as through the browser interface. Design, share, and manufacture, all in the same space with nothing extra to install or configure. Connect to the platform directly from Altium Designer without changing how you already design electronics. Altium 365 requires no additional licenses and comes included with your subscription plan.

Get real-time component insights as you design with Octopart built into Altium 365. Octopart is the fastest search engine for electronic parts and gives you the most up-to-date part data like specs, datasheets, cad models, and how much the part costs at different amounts etc. Right in the design environment so you can focus on your designs. Start with Altium Designer and Activate Altium 365. Search for electronic parts on Octopart.

RCWL-0516 Microwave Sensor Interfacing with Arduino:

RCWL-0516 Microwave Sensor Interfacing with Arduino

The VIN pin is connected with the Arduino 5V pin. GND is connected with the Arduino’s GND. And the Output pin is connected with the Digital Pin 12.

The 5V buzzer is connected with Digital Pin 4 through this general-purpose NPN transistor 2N2222. Now, let’s go ahead and take a look at the programming.

RCWL-0516 Microwave Sensor Arduino Programming:

int Sensor = 12;  
int buzzer = 4;  

void setup() {
  pinMode (Sensor, INPUT); 
  pinMode (buzzer, OUTPUT);   
  Serial.println("Waiting for motion");


void loop() {

     if(digitalRead(Sensor) == HIGH) // sensor outputs high signal or 1 when motion is detected
        digitalWrite(buzzer, HIGH);
     if(digitalRead(Sensor) == LOW)
        digitalWrite(buzzer, LOW);

For this sensor you don’t need to download and install any libraries. Just define the pins, then tell the controller which pins are going to be used as the input and output. And then in the loop() function write a simple code to turn ON the buzzer when any movement is detected. Using this code you can control a relay, simply remove the buzzer and connect a relay module with the digital pin 4 of the Arduino. You can also add code for the GSM module, if you want to send an SMS. You can check my projects on GSM module. Anyway, I have already uploaded this program and now let’s start with the practical demonstration.

Practical Demonstration:

For practical demonstration watch the video tutorial given at the end of this article.

Arduino RCWL-0516 Microwave Sensor for motion detection

When there is no obstacle in front of the sensor it works just perfectly. Now, I am going to put it inside a box, and let’s see if it can still detect any movements.

Arduino RCWL-0516 Microwave Sensor inside a box, and let’s see if it can still detect any movements

It can detect movement but the detection range is reduced.

Next, I tested it inside a Drawer to see if the microwaves from the RCWL-0516 sensor are powerful enough to penetrate through the wooden board.

Arduino RCWL-0516 Microwave Sensor inside a Drawer to see if the microwaves from the RCWL-0516 sensor are powerful enough to penetrate through the wooden board

The detection range was further reduced but it was working. So, it can be used inside drawers and cupboards for the security purposes.

Finally, I performed my final and ultimate test that is I put this sensor behind a brick wall to check if it could still detect moving objects and humans.

Arduino RCWL-0516 Microwave sensor behind a brick wall to check if it could still detect moving objects and humans

The detection range was really reduced, it could only detect me when I was very close to the brick wall. While on the other hand, the Gravity Microwave sensor V2.0 from the DFrobot could detect moving objects from behind the walls without any issues. So, that’s all for now.

Watch Video Tutorial:

Engr Fahad

My name is Shahzada Fahad and I am an Electrical Engineer. I have been doing Job in UAE as a site engineer in an Electrical Construction Company. Currently, I am running my own YouTube channel "Electronic Clinic", and managing this Website. My Hobbies are * Watching Movies * Music * Martial Arts * Photography * Travelling * Make Sketches and so on...

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button