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

The HC-SR505 Mini PIR (Passive Infrared) Motion Sensing Module is a compact, low-power sensor capable of detecting the presence of humans or animals by sensing the infrared radiation they emit. This module is widely used in various applications such as security systems, automatic lighting, and home automation projects due to its small form factor and ease of use.

• Motion-activated night lights
• Security alarms
• Automatic door openers
• Presence detection for energy-saving systems

• Operating Voltage: 4.5V to 20V
• Quiescent Current: <60uA
• Level Output Voltage: High 3.3V / Low 0V
• Delay Time: Adjustable (default 8s + -30%)
• Blockade Time: 2.5s (default)
• Trigger Method: Repeatable trigger
• Detection Angle: <100 degrees
• Detection Distance: Up to 3 meters
• Operating Temperature: -20 to +80 degrees Celsius

1. Connect the VCC pin to a power supply within the range of 4.5V to 20V.
2. Connect the GND pin to the ground of the power supply.
3. Connect the OUT pin to a digital input pin on a microcontroller, such as an Arduino UNO.

• Ensure that the power supply voltage does not exceed the maximum rating of 20V.
• Avoid placing the sensor in an environment with rapid temperature changes to prevent false triggers.
• The sensor should not be exposed to direct sunlight or placed near heating devices.
• Install the sensor away from wind sources such as air conditioners or fans.

// Define the PIR motion sensor pin
const int PIRPin = 2; // Connect HC-SR505 OUT pin to Arduino pin 2

void setup() {
  pinMode(PIRPin, INPUT); // Set the PIR pin as an INPUT
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  int motionState = digitalRead(PIRPin); // Read the PIR sensor output
  if (motionState == HIGH) {
    // If motion is detected, output a message
    Serial.println("Motion detected!");
    // Add your code here to handle the motion event
  } else {
    // If no motion is detected, output a different message
    Serial.println("No motion.");
  }
  delay(1000); // Wait for 1 second before reading again
}

• False triggers: Adjust the sensor's placement or orientation to minimize false triggers caused by environmental factors.
• No response: Check the power supply and connections to ensure the module is properly powered and connected.
• Intermittent operation: Ensure that the sensor is not exposed to direct sunlight or strong RF fields which may cause interference.

• If the sensor is not triggering, verify that the connections are correct and the power supply is within the specified range.
• In case of erratic behavior, reset the power to the module to clear any latched states.
• For issues with sensitivity or detection range, consider adjusting the sensor's position or the delay time if applicable.

Q: Can the HC-SR505 be used outdoors? A: The HC-SR505 is not waterproof and is best used indoors or in a protected outdoor environment.

Q: How can I adjust the delay time? A: The default delay time is approximately 8 seconds. To adjust it, you would need to replace the onboard timing resistor with one of a different value, which requires soldering and an understanding of the module's circuitry.

Q: Is it possible to power the HC-SR505 with a battery? A: Yes, as long as the battery voltage is within the 4.5V to 20V range, the HC-SR505 can be battery-powered.

Q: How can I reduce power consumption for battery-operated projects? A: You can reduce power consumption by using a lower supply voltage within the acceptable range and by minimizing the active time of any connected devices triggered by the sensor.