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

Engr Fahad

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Table of Contents

RCWL-0516 Microwave Sensor:

Arduino RCWL-0516 Microwave Sensor or the DFrobot Digital Microwave Sensor V2.0– I 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 Nano USB-C Type (Recommended)

RCWL-0516 Microwave Sensor

Gravity Digital Microwave Sensor V2.0

*Disclosure: These are affiliate links. As an Amazon Associate I earn from qualifying purchases.

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:

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:

C-Th

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

R-GN

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

R-CDS

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)

CDS

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.

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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() {

//Serial.begin(9600);

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);

delay(5000);

}

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.

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.

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.

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.

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.