How to Use HC-SR505 Mini PIR Motion Sensing Module: Examples, Pinouts, and Specs

The HC-SR505 Mini PIR Motion Sensing Module is a compact passive infrared (PIR) sensor designed to detect motion by sensing changes in infrared radiation, typically emitted by human bodies. This module is widely used in security systems, home automation, and energy-saving applications due to its small size, low power consumption, and reliable performance.

• Motion-activated lighting systems
• Intruder detection in security systems
• Automatic door openers
• Energy-efficient appliances
• DIY electronics and Arduino-based projects

The HC-SR505 module is designed for ease of use and integration into various electronic systems. Below are its key technical details:

The HC-SR505 module has three pins for easy connection:

The HC-SR505 Mini PIR Motion Sensing Module is simple to use and can be integrated into a variety of circuits. Follow the steps below to use the module effectively:

1. Power Supply: Connect the VCC pin to a DC power source (4.5V to 20V) and the GND pin to the ground.
2. Output Signal: Connect the OUT pin to the input pin of a microcontroller (e.g., Arduino) or directly to a load (e.g., an LED or relay) if the current requirements are met.

• Warm-Up Time: The module requires a warm-up time of approximately 10 seconds after power-up to stabilize.
• Detection Range: Ensure the module is placed within its specified detection range (up to 3 meters) for optimal performance.
• Avoid Obstructions: Do not place the module behind glass or other materials that block infrared radiation.
• Power Supply: Use a stable power supply to avoid false triggers.

Below is an example of how to connect and use the HC-SR505 module with an Arduino UNO to control an LED:

• Connect the VCC pin of the HC-SR505 to the Arduino's 5V pin.
• Connect the GND pin of the HC-SR505 to the Arduino's GND pin.
• Connect the OUT pin of the HC-SR505 to the Arduino's digital pin 2.
• Connect an LED (with a 220-ohm resistor) to digital pin 13 of the Arduino.

// HC-SR505 Mini PIR Motion Sensor with Arduino UNO
// This code turns on an LED when motion is detected.

const int pirPin = 2;  // HC-SR505 OUT pin connected to digital pin 2
const int ledPin = 13; // LED connected to digital pin 13

void setup() {
  pinMode(pirPin, INPUT);  // Set PIR pin as input
  pinMode(ledPin, OUTPUT); // Set LED pin as output
  digitalWrite(ledPin, LOW); // Ensure LED is off initially
  Serial.begin(9600); // Initialize serial communication for debugging
}

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

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

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

1. No Output Signal (OUT pin always LOW):

   • Ensure the module is powered correctly (4.5V to 20V DC).
   • Verify that the module has completed its warm-up time (10 seconds).
   • Check for obstructions blocking the sensor's field of view.

2. False Triggers (OUT pin goes HIGH without motion):

   • Ensure the module is not exposed to direct sunlight or heat sources.
   • Use a stable power supply to minimize noise and interference.

3. Short Detection Range:

   • Verify that the module is within its specified detection range (up to 3 meters).
   • Ensure the sensor is not obstructed by objects or materials that block infrared radiation.

Q1: Can the detection range or output duration be adjusted?
A1: No, the HC-SR505 module has a fixed detection range (up to 3 meters) and output duration (~8 seconds).

Q2: Can the module detect motion through glass?
A2: No, the module cannot detect motion through glass or other materials that block infrared radiation.

Q3: Is the module compatible with 3.3V systems?
A3: Yes, the module's output signal is 3.3V, making it compatible with 3.3V logic systems. However, the power supply voltage must be between 4.5V and 20V.

Q4: How can I increase the detection range?
A4: The detection range is fixed and cannot be increased. For longer ranges, consider using a different PIR sensor with adjustable settings.

By following this documentation, you can effectively integrate the HC-SR505 Mini PIR Motion Sensing Module into your projects and troubleshoot common issues with ease.