PIR Motion Sensor Module HC-SR501

Features:

• Operating Voltage: 4.8V to 20V
• Idle Power Consumption: < 50µA
• Active Power Consumption: ~65mA
• Detection Range: Adjustable from 3 to 7 meters
• Detection Angle: 120°
• Output Signal: Digital HIGH (3.3V) or LOW (0V)
• Adjustable Delay Time: 0.3 to 200 seconds (up to 10 minutes)
• Adjustable Sensitivity
• Trigger Modes: Single and Repeatable
• Compatible with Arduino, Raspberry Pi, and other microcontrollers

Pinout:

• VCC: 4.8V to 20V power input
• GND: Ground
• OUT: Digital output pin (HIGH when motion is detected)

Adjustments:

• Sensitivity: Rotate potentiometer CW to increase range (up to 7m), CCW to decrease (min 3m)
• Time Delay: Rotate CW to increase delay (up to 300s), CCW to decrease
• Trigger Mode Jumper:
  • L (Single Trigger): Output goes HIGH for set time; additional motion is ignored
  • H (Repeatable Trigger): Each motion resets the HIGH time

Principle of Operation:

The module detects infrared radiation changes using a pyroelectric sensor. When motion is detected, the output pin goes HIGH and remains so for a user-defined delay period, after which it goes LOW again.

Applications:

1. Security Systems
2. Home Automation (e.g., automatic lighting)
3. Robotics
4. Energy-saving Systems
5. Industrial Automation
6. Smart Cameras
7. Access Control
8. Wildlife Monitoring

Example Circuit:

Connection to Arduino with an LED on pin 13:

• VCC → Arduino 5V
• GND → Arduino GND
• OUT → Arduino Digital Pin 2
• LED → Arduino Digital Pin 13 + resistor

Arduino Code:

// Set up pins
int motionSensorPin = 2;
int ledPin = 13;

void setup() {
  pinMode(motionSensorPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int motionDetected = digitalRead(motionSensorPin);
  if (motionDetected == HIGH) {
    Serial.println("Motion detected!");
    digitalWrite(ledPin, HIGH);
    delay(1000);
  } else {
    digitalWrite(ledPin, LOW);
  }
}

Technical Details:

Resources:

• Link 1
• Link 2

Comparisons:

• HC-SR505 vs HC-SR501:
• HC-SR505: Higher sensitivity, 3m max range, 2.7V-12V, non-retriggerable
• HC-SR501: Adjustable range up to 7m, 4.8V-20V, retriggerable