Introduction: PIR Motion Detection Sensor With Arduino

In this instructables we are going to create a simple circuit with an Arduino and PIR motion sensor that will detect the movement of a living being. An LED will light ON when movement is detected.

Step 1: Things You Need

Here’s the required parts for this project
1x PIR Motion Sensor (HC-SR501)

Arduino UNO

1x LED

Jumper Cables


Step 2: Schmatics

Assemble all the parts by following the schematics below.

Step 3: Code

Upload the following code.

int led = 13; // the pin that the LED is atteched to
int sensor = 2; // the pin that the sensor is atteched to

int state = LOW; // by default, no motion detected

int val = 0; // variable to store the sensor status (value)

void setup()


pinMode(led, OUTPUT); // initalize LED as an output

pinMode(sensor, INPUT); // initialize sensor as an input

Serial.begin(9600); // initialize serial }

void loop()


val = digitalRead(sensor); // read sensor value

if (val == HIGH)


// check if the sensor is HIGH

digitalWrite(led, HIGH);

// turn LED ON delay(100);

// delay 100 milliseconds

if (state == LOW)


Serial.println("Motion detected!");

state = HIGH;

// update variable state to HIGH



else {

digitalWrite(led, LOW);

// turn LED OFF delay(200);

// delay 200 milliseconds

if (state == HIGH)


Serial.println("Motion stopped!");

state = LOW;

// update variable state to LOW




Step 4: Detecting Motion

So after connecting everything together and uploading the code into arduino you can see whenever any living being comes anywhere near to sensor then it gets triggered and LED turns ON and you can use this sensor in your motion triggered project.