How to interface a PIR (Passive Infrared) sensor with an Arduino:

Step 1: List of Components

You’ll need the following components:

● Arduino board (e.g. Arduino Uno) ● PIR sensor ● Jumper wires ● Breadboard (optional)

Step 3: Code

int pirPin = 2; // choose the pin for the PIR sensorint ledPin = 13; // choose the pin for the LEDint pirState = LOW; // we start, assuming no motion detectedint val = 0; // variable for reading the pin status void setup() { pinMode(ledPin, OUTPUT); // declare LED as output pinMode(pirPin, INPUT); // declare sensor as input Serial.begin(9600);} void loop(){ val = digitalRead(pirPin); // read sensor value if (val == HIGH) { // check if the sensor is HIGH digitalWrite(ledPin, HIGH); // turn LED ON if (pirState == LOW) { // we have just turned on Serial.println("Motion detected!"); pirState = HIGH; } } else { digitalWrite(ledPin, LOW); // turn LED OFF if (pirState == HIGH){ // we have just turned off Serial.println("Motion ended!"); pirState = LOW; } } delay(100); // short delay between readings}

Open the Arduino IDE and create a new sketch. Paste the following code: This code will turn on an LED when motion is detected by the PIR sensor, and print a message to the Serial Monitor in the Arduino IDE. You can modify the code to do something else when motion is detected, like triggering an alarm or sending an alert.

Step 4: Upload and Test

Connect your Arduino board to your computer and upload the code. Open the Serial Monitor in the Arduino IDE to see the messages printed when motion is detected. Move around in front of the PIR sensor to test it out.