The HC-SR501 PIR (Passive Infrared) Motion Sensor is the most reliable and widely used module for motion detection. At Electrapac, we recommend this sensor for anyone looking to add security features, automated lighting, or "human presence" detection to their Arduino or Raspberry Pi projects.

Product Overview

The HC-SR501 uses a pyroelectric sensor to detect infrared radiation (heat) emitted by humans and animals. When a person moves within the sensor's field of view, it triggers a Digital High signal. This module is famous for its highly adjustable nature; you can manually tune both the Sensitivity (distance) and the Time Delay (how long the signal stays on) using the onboard potentiometers.

Key Features for Electrapac Customers

• Adjustable Sensitivity: The "SENS" potentiometer allows you to set the detection distance, making it effective for small rooms or large hallways.

• Variable Time Delay: The "TIME" potentiometer lets you decide how long an LED or alarm stays active after motion is detected.

• Dual Trigger Modes: A small yellow jumper on the board allows you to choose between:

  • L (Non-repeatable): The output goes Low immediately after the time delay, even if motion continues.

  • H (Repeatable): The output stays High as long as motion is detected within the sensor's range.

• Fresnel Lens: The white "dome" is a multi-segmented lens that focuses infrared energy, increasing the sensor's accuracy and viewing angle.

• Low Power Consumption: With a standby current of less than 50µA, it is perfect for battery-powered security systems.

Wiring & Adjustment Guide

To get your security project running with parts from www.electrapac.com:

1. VCC: Connect to 5V–20V (usually the 5V pin on your Arduino).

2. OUT: Connect to a Digital Input pin (e.g., D2).

3. GND: Connect to Common Ground.

4. Calibration: After powering up, the sensor needs a "warm-up" period of 30 to 60 seconds to learn the ambient infrared signature of the room.

Primary Applications

• Security Alarms: Detecting intruders and triggering a siren or GSM alert.

• Automatic Lighting: Turning on room lights or staircase LEDs when someone enters.

• Touchless Switches: Creating hygienic, motion-activated dispensers or doors.

• Energy Saving: Automatically turning off computer monitors or fans when a room is empty.

Why Shop at Electrapac?

We source the HC-SR501 with high-quality BISS0001 processing chips to minimize "false triggers" and ensure consistent performance in varying temperatures. At www.electrapac.com, we provide the smart sensors that help your projects respond to the presence of people.