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How to Use PIR Motion Sensor: Examples, Pinouts, and Specs

Image of PIR Motion Sensor
Cirkit Designer LogoDesign with PIR Motion Sensor in Cirkit Designer

Introduction

A Passive Infrared (PIR) Motion Sensor detects motion by measuring changes in infrared radiation, typically emitted by warm bodies. It is a low-cost, low-power device widely used in motion detection applications. PIR sensors are commonly found in security systems, automatic lighting, and energy-saving devices. They are ideal for detecting human or animal movement within a specific range.

Explore Projects Built with PIR Motion Sensor

Use Cirkit Designer to design, explore, and prototype these projects online. Some projects support real-time simulation. Click "Open Project" to start designing instantly!
PIR Motion-Activated LED Light
Image of 0: A project utilizing PIR Motion Sensor in a practical application
This circuit is a simple motion-activated LED light system. The HC-SR505 Mini PIR Motion Sensing Module is powered by a 9V battery and detects motion, upon which it sends an output signal to turn on the red LED. The LED and the PIR sensor share a common ground with the battery, completing the circuit.
Cirkit Designer LogoOpen Project in Cirkit Designer
Arduino UNO Motion Detector with PIR Sensor and LED Indicator
Image of PIR: A project utilizing PIR Motion Sensor in a practical application
This circuit is a motion detection system using an Arduino UNO, a PIR sensor, and an LED. The PIR sensor detects motion and sends a signal to the Arduino, which then turns on the LED to indicate motion has been detected.
Cirkit Designer LogoOpen Project in Cirkit Designer
Battery-Powered Motion-Activated LED Light with PIR Sensor
Image of EIMS: A project utilizing PIR Motion Sensor in a practical application
This circuit uses a PIR motion sensor to detect movement and subsequently light up a red LED. The PIR sensor is powered by a 9V battery, and its output is connected to the LED through a 10k Ohm resistor to limit the current.
Cirkit Designer LogoOpen Project in Cirkit Designer
Battery-Powered PIR Motion Sensor Alarm with Relay and Buzzer
Image of motion detector using pir motio0n sensor: A project utilizing PIR Motion Sensor in a practical application
This circuit is a motion-activated alarm system. It uses a PIR motion sensor to detect movement, which triggers a relay module to activate a buzzer powered by a 9V battery, providing an audible alert.
Cirkit Designer LogoOpen Project in Cirkit Designer

Explore Projects Built with PIR Motion Sensor

Use Cirkit Designer to design, explore, and prototype these projects online. Some projects support real-time simulation. Click "Open Project" to start designing instantly!
Image of 0: A project utilizing PIR Motion Sensor in a practical application
PIR Motion-Activated LED Light
This circuit is a simple motion-activated LED light system. The HC-SR505 Mini PIR Motion Sensing Module is powered by a 9V battery and detects motion, upon which it sends an output signal to turn on the red LED. The LED and the PIR sensor share a common ground with the battery, completing the circuit.
Cirkit Designer LogoOpen Project in Cirkit Designer
Image of PIR: A project utilizing PIR Motion Sensor in a practical application
Arduino UNO Motion Detector with PIR Sensor and LED Indicator
This circuit is a motion detection system using an Arduino UNO, a PIR sensor, and an LED. The PIR sensor detects motion and sends a signal to the Arduino, which then turns on the LED to indicate motion has been detected.
Cirkit Designer LogoOpen Project in Cirkit Designer
Image of EIMS: A project utilizing PIR Motion Sensor in a practical application
Battery-Powered Motion-Activated LED Light with PIR Sensor
This circuit uses a PIR motion sensor to detect movement and subsequently light up a red LED. The PIR sensor is powered by a 9V battery, and its output is connected to the LED through a 10k Ohm resistor to limit the current.
Cirkit Designer LogoOpen Project in Cirkit Designer
Image of motion detector using pir motio0n sensor: A project utilizing PIR Motion Sensor in a practical application
Battery-Powered PIR Motion Sensor Alarm with Relay and Buzzer
This circuit is a motion-activated alarm system. It uses a PIR motion sensor to detect movement, which triggers a relay module to activate a buzzer powered by a 9V battery, providing an audible alert.
Cirkit Designer LogoOpen Project in Cirkit Designer

Technical Specifications

Below are the key technical details of a typical PIR Motion Sensor:

  • Operating Voltage: 4.5V to 20V DC (commonly 5V or 12V)
  • Current Consumption: < 50 µA (standby), ~65 mA (active)
  • Detection Range: 3 to 7 meters (adjustable in some models)
  • Detection Angle: ~120° (varies by model)
  • Output Signal: Digital (High: 3.3V or 5V, Low: 0V)
  • Warm-up Time: ~30 seconds after power-up
  • Operating Temperature: -20°C to 50°C

Pin Configuration and Descriptions

The PIR Motion Sensor typically has three pins. Below is the pinout description:

Pin Name Description
VCC Power supply input (4.5V to 20V DC)
OUT Digital output signal (High/Low)
GND Ground connection

Some PIR sensors may also include additional features such as sensitivity and delay time adjustment knobs.

Usage Instructions

How to Use the PIR Motion Sensor in a Circuit

  1. Power the Sensor: Connect the VCC pin to a 5V or 12V power source and the GND pin to the ground.
  2. Connect the Output: Connect the OUT pin to a microcontroller (e.g., Arduino) or directly to a device (e.g., relay module or LED).
  3. Adjust Settings: If your PIR sensor has sensitivity and delay time adjustment knobs, tune them as needed:
    • Sensitivity: Adjusts the detection range.
    • Delay Time: Sets how long the output remains HIGH after motion is detected.
  4. Wait for Warm-up: Allow the sensor to stabilize for ~30 seconds after powering it on.

Important Considerations and Best Practices

  • Avoid Direct Sunlight: PIR sensors are sensitive to infrared radiation, so avoid placing them in direct sunlight or near heat sources.
  • Minimize Interference: Keep the sensor away from moving objects like fans or curtains to prevent false triggers.
  • Mounting Height: Install the sensor at an appropriate height (e.g., 2-3 meters) for optimal detection.
  • Power Supply: Use a stable power source to avoid erratic behavior.

Example: Connecting PIR Motion Sensor to Arduino UNO

Below is an example of how to connect and use a PIR Motion Sensor with an Arduino UNO:

Circuit Connections

  • VCC: Connect to Arduino's 5V pin.
  • OUT: Connect to Arduino's digital pin 2.
  • GND: Connect to Arduino's GND pin.

Arduino Code

// PIR Motion Sensor Example with Arduino UNO
// This code reads the PIR sensor's output and turns on an LED when motion is detected.

int pirPin = 2;       // PIR sensor output pin
int ledPin = 13;      // Built-in LED pin on Arduino

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

void loop() {
  int motionDetected = digitalRead(pirPin); // Read PIR sensor output

  if (motionDetected == HIGH) { // If motion is detected
    digitalWrite(ledPin, HIGH); // Turn on LED
    Serial.println("Motion detected!");
  } else {
    digitalWrite(ledPin, LOW);  // Turn off LED
    Serial.println("No motion.");
  }

  delay(100); // Small delay to stabilize readings
}

Troubleshooting and FAQs

Common Issues and Solutions

  1. Sensor Not Detecting Motion:

    • Ensure the sensor is powered correctly (check VCC and GND connections).
    • Verify that the warm-up time (~30 seconds) has elapsed.
    • Check the sensitivity adjustment knob (if available) and increase the range.
  2. False Triggers:

    • Avoid placing the sensor near heat sources, reflective surfaces, or moving objects.
    • Ensure the sensor is not exposed to strong air currents.
  3. Output Signal Stuck HIGH or LOW:

    • Check the wiring and ensure the OUT pin is connected to the correct input pin on the microcontroller.
    • Verify the power supply voltage is within the sensor's operating range.

FAQs

Q1: Can the PIR sensor detect motion through glass?
A1: No, PIR sensors cannot detect motion through glass as infrared radiation does not pass through it effectively.

Q2: How do I increase the detection range?
A2: Use the sensitivity adjustment knob (if available) or ensure the sensor is mounted at an optimal height and angle.

Q3: Can I use the PIR sensor outdoors?
A3: Yes, but ensure it is housed in a weatherproof enclosure to protect it from rain and extreme temperatures.

Q4: Why does the sensor take time to stabilize after powering on?
A4: The sensor requires a warm-up period (~30 seconds) to calibrate its internal circuitry and avoid false triggers.