How to Use PIR Motion Sensor (Wokwi Compatible): Examples, Pinouts, and Specs

The PIR Motion Sensor is a Passive Infrared sensor that detects motion by measuring changes in the infrared levels emitted by objects in its field of view. When a living being, such as a human or animal, enters the sensor's range, it detects the change in infrared radiation and can trigger a response. This sensor is widely used in security systems, automatic lighting control, and various automation projects due to its non-intrusive nature and ease of integration with microcontroller platforms like Arduino.

• Voltage: Typically 5V to 12V DC
• Idle Current: <50uA
• Output Current: <100mA
• Detection Range: Up to 7 meters (23 feet)
• Detection Angle: Up to 120 degrees
• Output Type: Digital (High/Low signal)

1. Connect the VCC pin to a 5V power supply.
2. Connect the GND pin to the ground of the power supply.
3. Connect the OUT pin to a digital input pin on the Arduino.

• Ensure that the power supply voltage does not exceed the sensor's maximum rating.
• Avoid placing the sensor in an area with potential for rapid temperature changes, as this may cause false triggers.
• The sensor may take 1-2 minutes to calibrate upon initial power-up. During this time, it may trigger randomly.
• Use a pull-up resistor if the digital input pin on the microcontroller requires it.

// PIR Motion Sensor Example Code
int pirPin = 2; // Digital pin connected to the PIR sensor's output
int ledPin = 13; // LED connected to digital pin 13

void setup() {
  pinMode(pirPin, INPUT); // Initialize the PIR pin as an input
  pinMode(ledPin, OUTPUT); // Initialize the LED pin as an output
  Serial.begin(9600); // Start serial communication at 9600 baud
}

void loop() {
  int pirValue = digitalRead(pirPin); // Read the value from the PIR sensor
  if (pirValue == HIGH) { // Check if the PIR sensor is detecting motion
    digitalWrite(ledPin, HIGH); // Turn on the LED
    Serial.println("Motion detected!");
  } else {
    digitalWrite(ledPin, LOW); // Turn off the LED
    Serial.println("No motion detected.");
  }
  delay(1000); // Wait for 1 second before reading again
}

• Sensor always triggers: Ensure there are no heat sources or moving objects in the sensor's field of view during the calibration period.
• Sensor does not trigger: Check connections and ensure the sensor is powered correctly. Also, verify that the sensor's field of view is not obstructed.
• Intermittent triggering: This can be due to electrical noise. Use a pull-up resistor and ensure proper power supply decoupling.

• Calibration: Allow the sensor to calibrate for 1-2 minutes after powering up.
• Sensitivity: Adjust the sensitivity and time delay potentiometers on the sensor, if available.
• Testing: Use a simple LED circuit to test the sensor's output before connecting it to a microcontroller.

Q: How long does the sensor output stay high after detecting motion? A: This can vary based on the sensor model and settings of the time delay potentiometer.

Q: Can the sensor detect motion through walls or glass? A: No, the sensor cannot detect motion through solid objects.

Q: Is the sensor waterproof? A: Most PIR sensors are not waterproof unless specified by the manufacturer. It is recommended to use them indoors or in a waterproof enclosure if used outside.

Q: How can I adjust the range and sensitivity of the sensor? A: Some models come with potentiometers that allow you to adjust the sensitivity and the time the output signal stays high after detection.